Recent ucmp_paleobios items

Paleobiology Database User Guide Version 2.0

Sun, 17 May 2026 00:00:00 +0000

The Paleobiology Database is an online, non-governmental, non-profit public resource for paleontological data. It is organized and operated by a multi-disciplinary, multi-institutional, international group of paleobiological researchers. This is the second edition of the volume designed to be a comprehensive guide for Paleobiology Database users, both General and Contributory. It covers most database uses from data retrieval and mapping to data contribution of all types. It contains numerous examples to illustrate database use as well as definitions of terms and additional links to numerous other sources. We hope that this user guide will help all users access the great volume of data in the Paleobiology Database and lead others to start and continue to add data to the system.

New mammalian herbivore records from the Early to Middle Miocene Castilletes fauna, Colombia and late Neogene environmental change in northern South America

Fri, 5 Dec 2025 00:00:00 +0000

The Early to Middle Miocene mammal assemblage of the Castilletes Formation, Colombia records a diverse assemblage of mammals in the northern Neotropics prior to the Great American Biotic Interchange. We identify new records of herbivorous mammal taxa, with additional specimens of Huilatherium sp. and the first records of cf. Pericotoxodon sp., Miocochilius cf. M . anomopodus and ‘ Scleromys’ sp. All these genera are shared with other tropical Middle Miocene assemblages, including La Venta (Colombia) and Fitzcarrald (Peru) and increase the faunal similarity among them. Ecometric analysis of dental traits suggests a habitat change between the assemblages of the Castilletes Formation and the Ware Formation (Late Pliocene), consistent with results from other proxies that show increased opening and drying. In combination, these results support the utility of ecometric methods in Neogene South America and emphasise the importance of taxonomic...

Newly described specimens of leptarctine mustelids expand their geographic range in the western United States

Tue, 14 Oct 2025 00:00:00 +0000

Leptarctus is a morphologically distinctive carnivoran mammal occurring in Miocene deposits of North America and East Asia. In North American Leptarctus is mostly known from the Great Plains and Florida, but the single occurrence in China and recent description of well-preserved specimens in Oregon indicate that the western North American distribution of the genus is understudied. Here I document previously unreported specimens of Leptarctus and review other leptarctines housed in the collections of the University of California Museum of Paleontology (UCMP). Dental materials of at least four species of Leptarctus are present in the UCMP collections, encompassing occurrences from the Hemingfordian to Hemphillian North American Land Mammal Ages, adding to known records in the Great Plains, and expanding the paleogeographic range of L. wortmani into Nevada. Materials representing the genus in California are fragmentary but confirm the presence...

2025 Western Association of Vertebrate Paleontology Annual Meeting Abstracts

Fri, 22 Aug 2025 00:00:00 +0000

Abstracts from the 2025 annual meeting of the Western Association of Vertebrate Paleontology

New species of the deep-water bivalve genera Acesta (Limidae, Bivalvia, Mollusca) and a questionable Malletia (Malletiidae, Bivalvia, Mollusca) from the Eocene of southern California

Tue, 19 Aug 2025 00:00:00 +0000

Fossils of two rarely encountered molluscan bivalve genera, Acesta (Limidae, Bivalvia, Mollusca) and questionably Malletia (Malletiidae, Bivalvia, Mollusca) were collected from in the early Eocene Ardath Shale, La Jolla Group from La Jolla, San Diego County, California. These specimens represent new species easily distinguished from other members of the genera from the northeastern Pacific Cenozoic and Holocene. The new Acesta is similar in size and outline to the modern Philippine species A. rathbuni (Bartsch 1913), while the new Malletia is most similar to the Holocene northeastern Pacific species M. faba Dall (1897).

Paleogene marine bivalves of the deep-water Keasey Formation in Oregon, Part IA: The protobranchs (Nuculidae, Sareptidae, Pristiglomidae)

Thu, 10 Jul 2025 00:00:00 +0000

Systematic description and illustration of protobranch bivalves of the late Eocene–early Oligocene Keasey Formation in Oregon follows previous monographic treatments of the Keasey anomalodesmatans, heteroconchs and pteriomorphs. Of the three protobranch families documented here, this is the first recognition of Sareptidae and Pristiglomidae in the fossil record of the Northeastern Pacific and Cascadia Margin, as well as recognition of three undescribed species of Nuculidae. Small size and poor preservation contribute to previous failure to notice them in the field. New taxa include Nucula (Nucula) cascadensis, Ennucula keaseyesis, Sarepta oregonensis, Sarepta nascif, and Pristigloma mistensis. Nucula (Nucula) n. sp. is treated in open nomenclature pending discovery of additional material. Acila (Truncacila) nehalemensis is one of the most abundant and frequent bivalves...

Western Association of Vertebrate Paleontology Annual Meeting Abstracts PaleoBios 42(2):1-12

Wed, 9 Jul 2025 00:00:00 +0000

Abstracts from the 2024 Annual Meeting of the Western Association of Vertebrate Paleontology, held at Yavapai College, Prescott, Arizona

Multiple geniculated types in a single inoceramid (Bivalvia) species: “Inoceramus” nebrascensis

Tue, 11 Feb 2025 00:00:00 +0000

ABSTRACT Inoceramids have been studied extensively over the last 200 years and, along with ammonites, have become an important tool for Late Cretaceous biostratigraphy. Geniculation, the abrupt change in convexity/inflation of the valve disc, occurs in many inoceramids and has been recognized for decades. But despite extensive inoceramid research, it remains a relatively under-documented phenomenon. To understand the phylogenetic relationships within this cosmopolitan bivalve family, it is necessary to recognize the range of intraspecies variation. “ Inoceramus ” nebrascensis is known to geniculate, but its morphological variability has not been effectively documented. This study identifies five morphotypes of “I.” nebrascensis from a single locality of the Late Campanian Pierre Shale in South Dakota. The most common form is non-geniculated (Type I). The four geniculated forms include: marked positive geniculation (Type II); slight positive geniculation followed promptly...

Fossil leaves, fruits and seeds of the Late Eocene Teater Road flora near Post, Oregon, USA

Thu, 19 Dec 2024 00:00:00 +0000

The Teater Road flora, from a small outcrop of lacustrine shale exposed in Late Eocene sediments of the John Day Formation near Post, Oregon, USA, is presented based on abundant, well-preserved leaf and fruit impressions. We recognize 48 genera or morphotypes of leaves and 58 of reproductive structures, with the most abundant representatives including the aquatic fern, Salvinia, and a variety of angiosperms including Ulmaceae, Fagaceae, Betulaceae, Malvaceae, Simaroubaceae and Sapindaceae (Koelreuteria, Acer spp., Dipteronia). The Teater Road flora represents a diverse mixed mesophytic assemblage of interest for comparison with other Late Eocene floras of western North America and with the nearby Oligocene Gray Ranch flora. Analyses of foliar physiognomy give estimates of mean annual temperature of ca. 10.4 °C and mean annual precipitation of ca. 71 cm per year.

Temporalis attachment area as a proxy for feeding ecology in toothed whales (Artiodactyla: Odontoceti)

Mon, 1 Jan 2024 00:00:00 +0000

The temporalis is an important muscle used in biting and mastication, and whose morphology is strongly influenced by feeding ecology. Although the anatomy of this muscle and its relation to feeding function are well-studied in terrestrial mammals, few studies have examined its variation in whales. Our study focuses on quantifying the area of attachment for the temporalis muscle within the temporal fossa, calculating two metrics of comparison: A temporal fossa index (TFI) which is a size corrected measure of temporalis muscle attachment area, and a corrected temporal fossa index (CTFI), which also corrects for cranial telescoping. We calculated TFI and CTFI scores for 72 species of extant odontocetes as well as 37 species of extinct whale, including archaeocetes and toothed mysticetes. We statistically tested for differences related to diet and prey capture method using ANOVA. We then performed ancestral character state reconstruction (ACSR) for both metrics.

We found...

Reptiles from the late Eocene Jackson Group of Arkansas

Mon, 1 Jan 2024 00:00:00 +0000

New reptilian fossils from the latest middle Eocene to late Eocene Crow Creek local faunafrom the Jackson Group of St. Francis County, Arkansas, add four turtles and two crocodilians to the fauna. These include a new species of the carettochelyid Anosteira, the kinosternid Xenochelys, the dermatemydid Baptemys, an unidentified cheloniid, and crocodilians cf. Borealosuchus and an alligatorid. The giant snake, Pterosphenus schucherti, was also a member of the reptilian fauna. Several of these are the most easterly records for these taxa.

Geology, microstratigraphy, and paleontology of the lacustrine Truckee Formation diatomite deposits near Hazen, Nevada, USA, with emphasis on fossil stickleback fish

Mon, 1 Jan 2024 00:00:00 +0000

Diatomite deposits of the lacustrine Truckee Formation near Hazen, Northern Nevada, are of Miocene age (ca. 10.3 million years old) and consist of varved deposits within commercial mines. These exposed deposits have been primary source of paleontological samples of stickleback fish fossils (Gasterosteous doryssus) spanning 100,000 years. These samples have revealed stasis, rapid morphological and genetic evolution, and local extinction of G. doryssus against a background of changing diatom communities. Here, we draw on geological, limnological, anthropogenic, and bibliographical data to illustrate the geographic and paleontological context of the Hazen diatomite deposits. We include a stratigraphic section describing lithology and stickleback specimen frequency at a 1 mm resolution. This paper should help researchers identify patterns in fossil site distribution and better understand the geological processes that have shaped the area, spurring...

A late Eocene wood assemblage from the Crooked River Basin, Oregon, USA

Wed, 1 Nov 2023 00:00:00 +0000

Well-preserved silicified woods are common in the Pacific Northwest, USA. Localities near the town of Post, Oregon, provide insights into the late Eocene vegetation and climate ca. 36 million years ago and data for comparing both older and younger wood floras of the region. New investigations of the late Eocene Dietz Hill locality (UF 278) revealed woods belonging to the families Pinaceae (Keteleeria farjonii sp. nov.), Cupressaceae (Taxodioxylon sp.), Magnoliaceae (Magnolia hansnooteboomii sp. nov.), Lauraceae (Laurinoxylon sp. A and B), Platanaceae (Platanoxylon haydenii (Felix) Süss and Müller-Stoll, 1977), Fabaceae (cf. Styphonolobium sp.), Fagaceae (Fagus dodgei Wheeler and Manchester, 2021, Quercus sp., Red Oak type), Juglandaceae (Carya leroyii sp. nov.), Ulmaceae (Ulmus woodii Wheeler and Manchester, 2007), Sapindaceae (Aesculus constabularisii sp. nov., Klaassenoxylon...

Two new plioplatecarpine mosasaurs (Mosasauridae; Plioplatecarpinae) of the genus Ectenosaurus from the Upper Cretaceous of North America

Mon, 23 Oct 2023 00:00:00 +0000
Two new species of the rare mosasaur Ectenosaurus are reported from the Upper Cretaceous of North America. Ectenosaurus tlemonectes sp. nov. (YPM VP4673) consists of a largely complete skull and some associated post-cranial elements that were derived from an unknown level within the Smoky Hill Member of the Niobrara Chalk (upper Coniacian-lower Campanian), of Kansas, USA. Ectenosaurus shannoni sp. nov. (ALMNH:Paleo:5452) is described from a much more fragmentary specimen collected from the unnamed member of the Mooreville Chalk (upper Santonian-lower Campanian) of Alabama, USA. These new taxa can be distinguished from the other members of the genus, E. clidastoides (Merriam, 1894) and E. everhartorum Willman et al. (2021), by clear morphological differences in the skull and jaws. Two parsimony analyses of a data matrix consisting of 98 characters and 20 terminal taxa were carried out, the first without constraints and the second constrained...

A new aetosaur (Archosauria: Pseudosuchia) from the upper Blue Mesa Member (Adamanian: Early–Mid Norian) of the Late Triassic Chinle Formation, northern Arizona, USA, and a review of the paratypothoracin Tecovasuchus across the southwestern USA

Mon, 17 Jul 2023 00:00:00 +0000
The Late Triassic Chinle Formation in northern Arizona and Dockum Group in northwestern Texas preserve a high aetosaur biodiversity within the Adamanian teilzone, including Desmatosuchus spurensis, Desmatosuchus smalli, Calyptosuchus wellesi, Adamanasuchus eisenhardtae, Typothorax coccinarum, Paratypothorax sp., Tecovasuchus chatterjeei, and Sierritasuchus macalpini. Here, we present a new aetosaur Kryphioparma caerula gen. et sp. nov. from the upper Blue Mesa Member of the Chinle Formation, Adamanian teilzone, in northern Arizona. Kryphioparma caerula sp. nov. is documented based on several isolated osteoderms collected from the Placerias Quarry and Petrified Forest National Park. Although fragmentary, it is evident that the paramedian osteoderms of Kr. caerula exhibit a dorsal ornamentation composed of large, randomly oriented oblong pits; a low concentration...

2023 Western Association of Vertebrate Paleontology Annual Meeting: Program with Abstracts

Mon, 12 Jun 2023 00:00:00 +0000
Program and abstracts from the 2023 annual meeting of the Western Association of Vertebrate Paleontology.

Paleogene marine bivalves of the deep-water Keasey Formation in Oregon, Part II: The pteriomorphs

Thu, 8 Jun 2023 00:00:00 +0000
Systematic documentation of pteriomorph bivalves of the late Eocene–early Oligocene Keasey Formation in western Oregon follows previous monographic treatments of the anomalodesmatans and heteroconchs. It includes material from coeval Cascadia Margin strata in southwestern Washington in the context of major molluscan faunal turnover during the dramatic doubthouse climate transition from an ice-free tropical marine environment to the establishment of permanent polar ice caps and a cold temperate marine climate. The families represented are Crenellidae, Parallelodontidae, Glycymerididae, Limopsidae, Isognomonidae, Pectinidae, Propeamussiidae, and Limidae. New taxa include the genus Bathyisognomon and five new species: Limopsis squiresi, Bathyisognomon smithwickensis, Delectopecten kieli, Delectopecten keaseyorum, and Propeamussium (Parvamussium) mistensis. Small to minute mud pectens and glass scallops are among the most abundant...

First Cretaceous teleostean otolith assemblage (Arkadelphia Formation, upper Maastrichtian) from Arkansas, USA, early Gadiformes, and the Western Interior Seaway

Thu, 25 May 2023 00:00:00 +0000
The fortuitous discovery of Cretaceous (late Maastrichtian) teleostean otoliths in boring samples (17–31 m below ground level) from the Arkadelphia Formation near Cabot, Arkansas, USA, has consequential and overarching ramifications. The otolith assemblage, which is relatively large with 2,109 specimens, represents the first Mesozoic otolith assemblage described from Arkansas and one of the largest Cretaceous assemblages from a single USA site. The diversity of the assemblage is fairly large with a richness of 19 species with three additional taxa in open nomenclature and one unknown lapillus, which more than doubles the known actinopterygians from the Arkadelphia Formation. The otolith assemblage is extremely uneven in its diversity with one species, a putative siluriform Vorhisia vulpes Frizzell (1965b), accounting for approximately 73% of the total. The most unique feature of the otolith assemblage is the presence of cool-water gadiforms, which represent approximately...

Paleobiology Database User Guide Version 1.0

Sun, 26 Mar 2023 00:00:00 +0000

The Paleobiology Database is an online, non-governmental, non-profit public resource for paleontological data. It is organized and operated by a multi-disciplinary, multi-institutional, international group of paleobiological researchers. This volume is designed to be a comprehensive guide for Paleobiology Database users, both General and Contributory. It covers most database uses from data retrieval and mapping to data contribution of all types. It contains numerous examples to illustrate database use as well as definitions of terms and additional links to numerous other sources. We hope that this user guide will help all users access the great volume of data in the Paleobiology Database and lead others to start and continue to add data to the system.

The dentition of the extinct megamouth shark, Megachasma applegatei (Lamniformes: Megachasmidae), from southern California, USA, based on geometric morphometrics

Fri, 10 Feb 2023 00:00:00 +0000
Megachasma applegatei is an extinct megamouth shark (Lamniformes: Megachasmidae) commonly found in late Oligocene‒early Miocene marine deposits of the western USA, that is known only from isolated teeth exhibiting odontaspidid tooth design. In this study, we investigated the tooth morphometry of the extant megamouth shark (Megachasma pelagios) and smalltooth sandtiger (Odontaspis ferox: Odontaspididae) to aid in the reconstruction of the dentition of M. applegatei based on the tooth morphometry of 207 isolated fossil teeth from the lower Miocene Jewett Sand of southern California. Our landmark-based geometric morphometric analyses show that M. applegatei not only possesses a wider morphological range of teeth than M. pelagios, but also has morphological variation that can be corresponded to different tooth types in O. ferox, forming a unique heterodont dentition typical for macrophagous lamniform sharks known as the...

Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U.S.A.

Sun, 1 Jan 2023 00:00:00 +0000

Intensive sampling of uppermost Silurian to lowermost Devonian levels of the marine sequence of the Roberts Mountains Formation exposed in the Birch Creek II section, Nevada has yielded assemblages of vertebrate microremains dominated by acanthodian scales. Taxonomic assessment of the vertebrates represented shows a suite and succession of taxa most similar to those recorded from contemporary circum-Arctic assemblages, with scales of the poracanthodid acanthodians Poracanthodes punctatus, P. canadensis, Radioporacanthodes porosus and ischnacanthid Gomphonchus sandelensis most abundant below the Silurian–Devonian (S–D) boundary (as previously determined by conodont and graptolite occurrences), and stem chondrichthyan ‘acanthodians’ Nostovicina laticristata and other Nostovicina spp. (order, family indet.) the most abundant above the boundary. Just one endemic acanthodian taxon, Funicristata nevadaensis nov. gen....

Caecidae (Mollusca: Gastropoda) from late Miocene exposures of the “Imperial” Formation in Riverside County, California

Sun, 1 Jan 2023 00:00:00 +0000
Three Caecidae species from two genera have been recovered from the late Miocene “Imperial” Formation exposed in Super Creek, north and slightly east of Whitewater, Riverside County, southern California. These specimens record the first fossil Caecidae from California older than Pleistocene. The three taxa are Caecum brasilicum de Folin, 1874, Meioceras nitidum (Stimpson, 1851), and a new species of Caecum named C. roederi n. sp., in honor of friend and colleague Mark Roeder. Caecum brasilicum and M. nitidum occur today in the central-western Atlantic Ocean and their previous fossil occurrences are also there. The occurrence of these Atlantic species in the “Imperial” Formation is not surprising as > 8% of the Super Creek fauna has a Caribbean origin at the species level because of the then submerged Panama seaway that allowed water from the western Atlantic to flow freely into the eastern Pacific.

A methane seep from the deep-marine, late Eocene Keasey Formation, Rock Creek, Columbia County, Oregon

Sun, 1 Jan 2023 00:00:00 +0000

Investigation of a deep-water carbonate seep complex in the late Eocene Rock Creek section of the Keasey Formation, northwestern Oregon State, provides new data on marine carbonate seep occurrences in the formation. Methane seep carbonate bodies, with a diversity of seep-related invertebrate taxa are scattered across western Washington and the Rock Creek seep described here, together with the previously described Vernonia-Timber Road seep and Crinoid lagerstätte at Mist expands the Keasey Formation methane seep signatures. These three sites illustrate different points on a continuum from effusive to diffusive expulsion of methane and biotic chemosynthetic activity. Lithologic descriptions include a richly fossiliferous carbonate body named the Primary seep site, carbonite pipes interpreted as flow conduits comprise the Secondary Site, and minor pockets of blebby nodules is the Tertiary site, all within a 35 m stratigraphic section. Lithologic facies contain six named and characterized...

A new fossil Euspira? (Mollusca: Gastropoda: Naticidae) from the Gubik Formation on the North Slope of Arctic Alaska

Sun, 1 Jan 2023 00:00:00 +0000

A new naticid gastropod, Euspira? louiemarincovichi n. sp., is described from the Pliocene to Pleistocene age Gubik Formation on the North Slope of Alaska between Skull Cliff in the west and the Kogru River/Teshekpuk Lake area in the east. It is easily distinguished from all other Atlantic, Pacific and Arctic oceans naticids by its fine radial and somewhat stronger spiral ribs. This new species lived during a time when water temperatures were warmer in the Arctic than today based on the occurrence of the gastropod genus Littorina with which this new species co–occurs. As such, Euspira? louiemarincovichi likely lived in the upper intertidal zone on hard substrate and were not present where sea–ice impinges on the shoreline. Based on co–occurrences of extinct species and the temperature regime indicated by Littorina, of significantly warmer temperatures, and some associated species, this new species probably lived during the Bigbendian and...

Acanthodian fauna from the Early Devonian (Emsian) of Death Valley, California

Sun, 1 Jan 2023 00:00:00 +0000

A limited assemblage of disarticulated remains from stem chondrichthyan (acanthodian) gnathostomes was found associated with more abundant pteraspidiform and cyathaspidiform (agnathan) plates and plate fragments as well as actinolepid placoderm remains in the Lippincott Member of the Lost Burro Formation, southeastern California. The acanthodian material comprises ischnacanthiform, Bryantonchus, and Machaeracanthus fin spines, ischnacanthiform dentigerous jaw bones, and an endoskeletal scapulocoracoid. The assemblage mostly matches that from the Emsian Sevy Dolomite and the lower Grassy Flat Member of the Water Canyon Formation of Utah and Nevada. Machaeracanthus has not been recorded from the latter strata, but has been described from the Coils Creek Member (?Emsian), McColley Canyon Formation, Nevada.

Washington State trigoniids (Bivalvia) from the conglomerate of Patterson Lake (Early Cretaceous)

Sun, 1 Jan 2023 00:00:00 +0000

Despite more than 150 years of research on the Jurassic and Cretaceous trigoniid bivalves of the Pacific Coast of North America, little mention is made of Washington State trigoniids. In this study, five trigoniid species from the Methow Basin are documented from three sites in the Lower Cretaceous conglomerate of Patterson Lake (cPL). Three of the species, Yaadia whiteavesi, Columbitrigonia condoni, and Notoscabrotrigonia oregana, are well-known in the literature. The other two, Parvitrigonia n. gen. cooperi n. sp. and Earlpackardia methowensis n. sp. are undescribed rutitrigoniids. These identifications revise the faunal lists from previous geological studies of the Methow Basin and allow a middle Albian age assignment to the upper portion of the cPL.

Revision of northeast Pacific Paleogene cypraeoidean gastropods (Mollusca), including recognition of three new species: Implications for paleobiogeographic distribution and faunal turnover

Sun, 1 Jan 2023 00:00:00 +0000

The Paleogene cypraeoidean fauna of the northeast Pacific region (NEP), extending from Vancouver Island, British Columbia, Canada southward to Baja California Sur, México, consists of 12 genera, 20 named species (three of which are new), six open-nomenclature species, one Cypraeidae, indeterminate to genus and species, one cf. species, and four nomina dubia. All taxa are figured here. Species reassigned at the genus level are Protocypraea? simiensis (Nelson, 1925) and Luponovula maniobraensis (Squires and Advocate, 1986). Improved documentation of known NEP species include Propustularia kemperae (Nelson, 1925), Grovesia castacensis (Stewart, 1926) [1927]), G. mathewsonii (Gabb, 1864), and Eratotrivia crescentensis (Weaver and Palmer, 1922). The three new species, Subepona leahae, Bernaya kaylinae, and Eocypraea judithsmithae are from the upper lower Eocene Llajas Formation of Simi Valley,...

Nucella demouthae, a new Late Miocene muricid gastropod from Northern California, U.S.A.

Sun, 1 Jan 2023 00:00:00 +0000

Nucella demouthae n. sp. is a new muricid described from the late Miocene part of the Wilson Grove Formation in Sonoma County, central California. It is distinguished from other modern and fossil California Nucella by its small size with faint to moderately strong radial sculpture, and its thickened and recurved outer lip with two denticles in the aperture. This rocky shore predatory gastropod has been found only at Bloomfield Quarry, north of the town of Bloomfield in Sonoma County, in the lowest part of the Wilson Grove Formation, which has been dated between 9.3 and 6.2 Ma, this time period falling within the late Miocene “Jacalitos” California provincial molluscan stage.

The extinct limpet Lottia edmitchelli (Lipps, 1963) from the Southern California Bight, U.S.A.

Mon, 27 Jun 2022 00:00:00 +0000
New specimens of the extinct limpet Lottia edmitchelli (Lipps, 1963) (Mollusca: Gastropoda: Lottidae) collected during a geologic survey of the northern-most California Channel Islands by United States Geological Survey personnel and examination of museum collections record previously unreported occurrences of this species on San Miguel, Santa Rosa and San Clemente Islands in the Southern California Bight. Previously this species was reported as Late Pleistocene to Holocene in age with occurrences on San Nicolas Island and the Palos Verdes Peninsula. The single specimen identified from the California mainland (Palos Verdes Peninsula) of Holocene age is regarded as an atavism in the L. scabra population. Eliminating this single specimen results in L. edmitchelli being a strictly fossil species with occurrences reported here from San Clemente, San Miguel, San Nicolas, and Santa Rosa Islands in deposits of possibly Calabrian Stage of the International Commission on Stratigraphy (=early...

The earliest Ancistrolepis (Gastropoda: Buccinidae) and its geologic implications

Fri, 8 Apr 2022 00:00:00 +0000
The buccinid gastropod Ancistrolepis carolineae Squires, 1984 is the earliest known and shallowestmarine species belonging to the extant genus Ancistrolepis Dall, 1895, which is endemic to the NorthPacific region. This species is of late early Eocene (Ypresian Stage) age and is about 7 million years older than the previously oldest known record (late Eocene) of the genus. This rare species occursat several localities in a 1-m thick bed (“Stewart bed”) of fossiliferous shallow-marine sandstone within the Llajas Formation, on the north side of Simi Valley, Ventura County, southern California.The “Stewart bed” contains a rich fauna of subtropical mollusks and other invertebrates, which lived just below effective wave base, at the distal edge of a braid delta, immediately adjacent to an upper bathyal prodelta/slope environment, where a rich microfauna of calcareous nannofossils and benthic foraminifers lived. Dispersal of A. carolineae would have been either...

Early Oligocene (Rupelian) fishes (Chondrichthyes, Osteichthyes) from the Ashley Formation (Cooper Group) of South Carolina, USA

Thu, 31 Mar 2022 00:00:00 +0000
Matrix surrounding a dermochelyid carapace and two cetacean skulls recovered from the Givhans Ferry Member of the Ashley Formation (lower Oligocene, Rupelian Stage) in South Carolina, USA yielded a surprisingly diverse assemblage of euselachian and teleost fishes. We identified 21 elasmobranch taxa, including 13 selachians and eight batoids, nearly all of which are known to occur in the overlying upper Oligocene (Chattian) Chandler Bridge Formation. Notable occurrences within the Ashley Formation paleofauna include a new shark, Scyliorhinus weemsi n. sp., and the first South Carolina Oligocene records of Squalus sp., Pristiophorus sp., and Pachyscyllium sp. Numerous teleost taxa were also documented based on isolated teeth, including species of Albulidae, Paralichthyidae, Osteoglossidae, Sparidae, Sciaenidae, Sphyraenidae, Scombridae, Trichiuridae, and possibly Labridae.

First record of the chancelloriid Allonnia from the middle Cambrian Wheeler Formation (Drumian, Miaolingian) of western Utah

Sat, 1 Jan 2022 00:00:00 +0000

A newly described specimen of chancelloriid represents the first occurrence of Allonnia in the middle Cambrian Wheeler Formation of Utah. This occurrence fills a geographic gap in the genus’s distribution from the Burgess Shale Formation (British Columbia) to the El Gavilán Formation (Sonora). It is also the geologically youngest occurrence of the genus in North America.

Arcoid bivalve biodiversity during Eocene doubthouse cooling: Contrasting the active Cascadia Margin coldspot with the intracratonic Paris Basin hotspot

Thu, 28 Oct 2021 00:00:00 +0000
Response to the Eocene doubthouse interval of global climate cooling (53–33.5 Ma) is explored in arcoid bivalves of the families Parallelodontidae, Cucullaeidae, Arcidae, and Noetiidae. An anomalous biodiversity hotspot in the intracontinental Paris Basin of Northern Europe is contrasted with an equally anomalous coldspot at comparable latitude on the tectonically active Cascadia Margin of western North America. Reevaluation of arcoid shell morphology and an annotated glossary of shell features accompanies illustration and discussion of eight exemplar species, identifying new characters and distinguishing those with a strong phyletic signal from those representing functional convergence or developmental differences specific to size or age. Biodiversity anomalies cannot be attributed to any single factor. However, contributing factors include tectonic setting, correlates of bathymetric and sedimentary setting, sediment geochemistry, ocean gateway events, reorganization of current...

Reconstructing oyster paleocommunity structure over the last 3.6 million years: A southern California case study

Sat, 21 Aug 2021 00:00:00 +0000
We culled abundance record data from the NSF-funded TCN, Eastern Pacific Invertebrate Communities of the Cenozoic (EPICC), including all southern California localities that recorded the presence of oysters from the last 3.6 million years to document how oyster communities change through time. In total, over 120,000 specimens from 78 localities throughout southern California (i.e., Los Angeles, Orange, and San Diego counties) were examined. The data were broken down into four-time bins: late Pliocene, middle Pleistocene, late Pleistocene, and Holocene. Using multivariate statistics, several statistically coherent groups based on occurrences and abundances through time were indentified. Results indicate that the late Pliocene coherent groups possessed a loose, facultative, individualistic community structure that allowed taxa to shift their latitudinal gradients as they tracked shifting environments. The dominant oyster—Dendrostrea vespertina—as well as other taxa, became...

The first in situ collection of a mosasaurine from the marine Breien Member of the Hell Creek Formation in south-central North Dakota, USA

Thu, 19 Aug 2021 00:00:00 +0000
The upper Maastrichtian Breien Member situated within the lower portion of the Hell Creek Formation in south-central North Dakota records one of the last transgressions of the Western Interior Seaway (WIS) during the terminal Cretaceous. A fragmentary articular-prearticular complex and isolated vertebra belonging to a mosasauroid were recovered in 2016 from sandstones and mudstones deposited in a nearshore marine paleoenvironment within the southern arm of the bisected WIS. The medially-rotated retroarticular process on the articular-prearticular complex, the shape of the glenoid fossa, along with the morphology of the isolated vertebra, facilitate a conservative referral to a large-bodied mosasaurine such as Mosasaurus or Prognathodon. The rocks of the Breien Member provide paleontologists a unique glimpse of intracontinental marine ecosystems immediately prior to the end of the Cretaceous Period. This discovery provides additional evidence that the latest Maastrichtian...

New proboscidean material from the Siwalik Group of Pakistan with remarks on some species

Mon, 12 Jul 2021 00:00:00 +0000
Over the years a diverse assemblage of proboscidean remains has been recovered from the Lower to Upper Siwalik Subgroups of Pakistan and India. This article reports newly discovered dental material of tri- and tetralophodont proboscideans that includes cf. Paratetralophodon hasnotensis and Choerolophodon sp., and a Gomphothere gen. et sp. indet., recently collected from late middle to late Miocene localities of the Pakistani Siwalik Group, with a brief history of these species. The partial premolar of cf. Pa. hasnotensis is described for the first time from the Siwalik Group, recovered from the Dhok Pathan Formation, and the specimens reported herein are the latest to be described after a 38-year gap from previously described material for this species. A preliminary survey of the literature and previously described material of Siwalik species suggests a revision of Siwalik Group proboscideans is much needed.

The first records of Sinclairella (Apatemyidae) from the Pacific Northwest, USA

Wed, 19 May 2021 00:00:00 +0000
Apatemyidae are a rare and enigmatic group of small insectivorous mammals that lived in North America and Europe in the Paleogene. The last known apatemyids in North America are two species in the genus Sinclairella, known from sites in the Great Plains and Florida. Here, I formally describe an upper second molar and lower incisor of the apatemyid, Sinclairella dakotensis, from the incredibly well-studied Turtle Cove Member of the John Day Formation in Oregon. These early Arikareean age specimens represent the first records of the family west of the Rocky Mountains. Sinclairella dakotensis filled a ‘woodpecking’ niche unlike any other mammal known from the region, and its co-occurrence with a number of forest-adapted mammal species is consistent with previous interpretations of environments at the time having been dominated by woodlands.

Taphonomic bias in collections of horse phalanges from the Barstow Formation (Miocene) and Rancho La Brea (Pleistocene) of California, USA

Thu, 22 Apr 2021 00:00:00 +0000
Isolated equid phalanges are relatively common finds in the Barstow Formation (Miocene, 19 to 13 million years ago, southern California), but anecdotal observations suggested that not all positions (proximal, middle, and distal/ungual) of the primary digit (digit III) are recovered with equal frequency. Our sample includes primarily surface-collected phalanges from the Barstow Formation, which we compare with phalanges of Pleistocene horses from Pit 3 and Pit 77 from Rancho La Brea (Los Angeles, California). The null hypothesis is that the three positions of phalanges should be equally common. Our Barstow sample includes 228 proximal, 151 middle, and 36 distal phalanges. A chi-square test (p<0.001) is consistent with preservation bias in phalangeal frequency for the full Barstow Formation sample, and this pattern generally holds within sub-samples by locality or depositional environment. Pit 3 of La Brea produced 163 proximal, 144 middle, and 103 distal phalanges. A chi-square...

Califrapana: a new genus of California and Bája California late Oligocene to early Miocene muricids previously attributed to the genus Rapana (Mollusca: Gastropoda: Muricidae)

Thu, 15 Apr 2021 00:00:00 +0000
Califrapana n. gen., is proposed for California late Oligocene to early Miocene muricids attributed previously to the possibly Paleocene to modern western Pacific and Indian oceans genus Rapana. Four fossil species have been assigned to Rapana in the eastern Pacific. One of these species, R. perrini Clark and Arnold (1923), should be placed in another genus, the other species Purpura vaquerosensis Arnold (1907), R. imperialis Hertlein and Jordan (1927), and R. serrai Wiedey (1928) are synonymized here with the morphologically variable species Califrapana vaquerosensis n. comb. We confirm C. vaquerosensis is an index fossil for the lower and middle “Vaqueros” California provincial molluscan stage of late Oligocene to early Miocene age in southern California and Bája California, México, although the lack of numerical dating and the misuse of lithostratigraphic and biostratigraphic names had made that...

New remains of middle Miocene equids from the Cajon Valley Formation, San Bernardino National Forest, San Bernardino County, California, USA

Thu, 25 Feb 2021 00:00:00 +0000
New material of three equids is described from the middle Miocene Cajon Valley Formation in San Bernardino National Forest, San Bernardino County, California. The material includes teeth of Archaeohippus mourningi, Scaphohippus sumani, and Parahippus brevidens. Scaphohippus intermontanus is considered a junior subjective synonym of S. sumani. Parahippus brevidens is identified from an upper molar that closely resembles the morphology of the holotype as well as referred specimens of Pa. brevidens from the Mascall Formation in Oregon and the Temblor Formation in California. The presence of Pa. brevidens in the Cajon Valley Formation represents a geographic range extension for the taxon of over 400 km. Interesting ecological implications emerge for the Cajon Valley Formation when compared to the nearby Barstow Formation, including the presence of chalicotheres and apparent lack of Hypohippus affinis...

Checklist of California Paleogene–Neogene marine Mollusca since Keen and Bentson (1944)

Sat, 6 Feb 2021 00:00:00 +0000
This checklist is a sequel to the one published by A. Myra Keen and Herdis Bentson in 1944 and is an alphabetical listing of California marine Paleogene–Neogene mollusk species or subspecies described and/or figured in the published literature spanning the interval of 1944 through 2020. The original data are given for each species and subspecies of bivalves, gastropods, chitons (polyplacophorans), scaphopods, and cephalopods. Where detected, formation names, ages, taxonomy, systematics, and specimen disposition were corrected. A total of 559 genera and 1,698 species/subspecies were tabulated, with the bivalves and gastropods being the most abundant taxa. Bivalve and gastropod diversity steadily built up during the Paleocene, nearly doubled during the Eocene warm time, declined greatly during the cool time of the Oligocene, rebounded to its highest peak in the Miocene and then declined slightly during the Pliocene. The other classes represented only minor faunal components. Chitons...

New dinosauromorph specimens from Petrified Forest National Park and a global biostratigraphic review of Triassic dinosauromorph body fossils

Thu, 12 Nov 2020 00:00:00 +0000
Dinosauromorph specimens from Petrified Forest National Park have been recovered from four major collecting efforts since 1982, including the most recent paleontological inventory of new park lands acquired in 2011. Additionally, an emphasis on understanding the stepwise acquisition of character traits along the dinosaurian lineage has helped identify previously collected specimens in museum collections. Here we briefly describe and use apomorphies to identify 32 additional dinosauromorph specimens found at Petrified Forest National Park, bringing the total number of dinosauromorph specimens presently known from the park to 50, a 600% increase since the year 2000. These specimens are all Norian in age and come from the Blue Mesa Member, Sonsela Member, and Petrified Forest Member of the Chinle Formation. These include the proximal end of a tibia that represents the oldest unambiguous dinosaur specimen from the Chinle Formation. We then contextualize these specimens with the dinosauromorph...

First description of the fossil otolith-based sciaenid, Equetulus silverdalensis n. comb., in the Gulf Coastal Plain, USA, with comments on the enigmatic distribution of the species

Tue, 1 Sep 2020 00:00:00 +0000
The fossil otolith-based sciaenid genus Equetulus is known almost exclusively from South America, the Caribbean, and Central America, with the various species ranging in age from the late Oligocene to late Miocene. The only exception to this geographical distribution is the isolated occurrence of Equetulus silverdalensis n. comb. in the Belgrade Formation (latest Oligocene–early Miocene) in the Atlantic Coastal Plain of the USA (North Carolina) and a mention of its occurrence in the Chickasawhay Limestone (late Oligocene) in the Gulf Coastal Plain of the USA (Mississippi). However, sampling of the Paynes Hammock Sand (late Oligocene, Chattian) near Millry, Alabama, USA, resulted in the discovery of an otolith representing the first occurrence of E. silverdalensis in Alabama and the first systematic description of the species from the Gulf Coastal Plain of the USA. These occurrences suggest a potential distribution of this fossil species from Atlantic...

Faunal change in Cretaceous endemic shallow-marine bivalve genera/subgenera of the northeast Pacific

Tue, 19 May 2020 00:00:00 +0000
Endemic shallow-marine Cretaceous bivalves in the northeast Pacific region (NEP), extending from southwestern Alaska to the northern part of Baja California Sur, Mexico, are tabulated and discussed in detail for the first time. Twenty-three genera/subgenera are recognized. Their first appearance was in the Valanginian, and their biodiversity continued to be very low during the rest of the Early Cretaceous. The bivalves of the middle Albian Alisitos Formation in northern Baja California are excluded because they did not live in the NEP. The highest number (13) of NEP endemic bivalve genera/subgenera occurred during the Turonian, which was the warmest time of the Cretaceous. At the Turonian/Coniacian boundary, when cooler waters migrated southward, there was a moderate dropoff in endemics that persisted until an origination event near the beginning of the early Maastrichtian, when 11 were present. Five of the 11 were present also during the Turonian, but the others were newcomers....

A new Lyropecten (Pectinidae, Bivalvia, Mollusca) from the central California Miocene, USA

Tue, 21 Apr 2020 00:00:00 +0000
A new pectinid, Lyropecten terrysmithae n. sp., has been recognized in middle to late Miocene rock units referred to as the Monterey Formation and Santa Margarita Sandstone in the southern Salinas Valley, central California. Previously, L. terrysmithae had been identified as a flat form belonging to either L. estrellanus or L. catalinae, then more recently to Argopecten sp. The earlier assignments were based on its moderate size and a radial rib count nearly identical to these taxa. However, its hinge, flat unledged valves, looped lamellar growth lines, and hinge crura set L. terrysmithae apart from Argopecten and all species of Lyropecten. Localities where it occurs in the Salinas Valley that can be accurately dated are from the late middle to middle late Miocene “Margaritan” California provincial molluscan stage. While L. terrysmithae has been collected at other sites, those localities lack diagnostic...

Epiplastral and geographic variation in Echmatemys, a geoemydid turtle from the Eocene of North America: A multi-tiered analysis of epiplastral shape complexity

Wed, 5 Feb 2020 00:00:00 +0000
Numerous geoemydid turtle fossils from the extinct genus Echmatemys have been recovered from the middle Eocene Uinta Formation, Uinta Basin, Utah over the past several decades. Here, we tested whether co-occurring Uintan species Echmatemys callopyge and E. uintensis can be reliably differentiated based on epiplastral morphology, and whether their geospatial distributions overlapped significantly. The geographic spatial and stratigraphic distributions of Uinta Basin E. callopyge and E. uintensis specimens were compared using ArcGIS and analysis of variance (ANOVA). The analysis revealed overlapping geographic distributions of these two species, and no significant differences in stratigraphic dispersal. This finding of extensive geospatial overlap between the two Uintan Echmatemys species highlights the need for accurate taxonomic identification, such as the gular scale morphology validated here. In addition, we sought to address...

Two new Miocene limpets (Fissurellidae) from southern California, with notes on other fossil occurrences of the family in northwestern North America

Thu, 26 Dec 2019 00:00:00 +0000
Two new fissurellid limpets (Mollusca: Gastropoda: Fissurellidae), Fissurella? stantoni n. sp. and Scelidotoma aldersoni n. sp., are described from Miocene deposits in southern California. Fissurella? stantoni is described from a single specimen from the middle Miocene Topanga Canyon Formation in the Santa Monica Mountains, Los Angeles County, California. Scelidotoma aldersoni is described from two specimens, one from the middle Miocene Topanga Canyon Formation, and another provisionally (cf.) identified specimen of an internal mold from the middle Miocene “Vaqueros” Formation on Santa Cruz Island, Santa Barbara County, southern California. Other unreported fossil occurrences of Scelidotoma are a juvenile specimen attributed only to genus collected in the middle Eocene Crescent Formation in Washington state and S. bella from the Pliocene part of the San Diego Formation, San Diego County, California. The Scelidotoma...

A new drepanosauromorph, Ancistronychus paradoxus n. gen. et sp., from the Chinle Formation of Petrified Forest National Park, Arizona, USA

Sun, 15 Dec 2019 00:00:00 +0000
Drepanosauromorpha is an extinct group of reptiles known from the Middle Triassic to Late Triassic (237–212 Ma). The clade currently includes seven genera (Avicranium, Dolabrosaurus, Drepanosaurus, Hypuronector, Kyrgzsaurus, Megalancosaurus, and Vallesaurus) that are known from fossils collected in Europe, North America, and Asia. These discoveries have helped shape our understanding of the biology and diversity of drepanosauromorphs. Here we describe Ancistronychus paradoxus n. gen. et sp. from the Chinle Formation in Petrified Forest National Park, Arizona based on the ungual phalanx of the second digit of the manus. A characteristic that this taxon shares with Drepanosaurus unguicaudatus is the pronounced size of the ungual relative to the penultimate element. It differs significantly from D. unguicaudatus and the Hayden Quarry Drepanosaurus in the shortened proximal dorsoventral height of the claw, its great transverse breath, the...

A protocol for differentiating late Quaternary leporids in southern California with remarks on Project 23 lagomorphs at Rancho La Brea, Los Angeles, California, USA

Fri, 13 Dec 2019 00:00:00 +0000
Leporid remains are common in Quaternary fossil assemblages and are useful paleoenvironmental indicators. Identifying leporid fossils to species is challenging, though previous work has shown that identifications are more feasible if fossils can be narrowed down to a subset of potential species occurring across limited spatial scales. We sampled 120 adult and nine juvenile dentaries of six extant western North American species (Lepus americanus, L. californicus, L. townsendii, Sylvilagus audubonii, S. bachmani, and S. nuttallii) to establish useful characters for genus and species-level identification of late Quaternary leporid fossils in California. Most individuals can be differentiated from individuals of other species using a combination of lower third premolar enamel folding patterns and dental measurements. However, it is difficult to discriminate dental elements among L. californicus and L. townsendii...

Miocene marine macropaleontology of the fourth bore Caldecott Tunnel excavation, Berkeley Hills, Oakland, California, USA

Tue, 16 Jul 2019 00:00:00 +0000
Excavation of the new fourth bore of the Caldecott Tunnel in the Berkeley Hills, Oakland, California reveals two faunas attributed to an unnamed glauconitic mudstone (=Sobrante Formation and mapped as Tsm) and the Claremont chert (both of Graymer 2000). The fossil assemblage from the unnamed glauconitic mudstone, referred to here as the Tsm Caldecott Tunnel fauna, consists of 32 taxa: one bryozoan, 22 Mollusca (16 Bivalvia, five Gastropoda and one Scaphopoda), two Arthropoda (one Decapoda and one Maxillopoda), two Echinodermata (one Crinoidae and one Echinoidea), and five Chordata. Mollusks indicate a middle Miocene age based on the co-occurrence of the provisionally identified bivalves Acila empirensis, Anadara osmonti, Yoldia submontereyensis, Y. supramontereyensis and the gastropod genera Bruclarkia and Trophoscyon. This fauna was likely deposited at water depths between 350 and 400 m. Although several taxa from shallower depths are present, these...

Nestling-sized hadrosaurine cranial material from the Hell Creek Formation of northeastern Montana, USA, with an analysis of cranial ontogeny in Edmontosaurus annectens

Mon, 15 Jul 2019 00:00:00 +0000
Despite over a century of intense collecting, the Hell Creek Formation has produced exceedingly few specimens of small juveniles and nestling-sized dinosaurs. Here, we report on the first cranial material of nestling-sized hadrosaurid dinosaurs from the formation. The specimens were recovered from the Sandstone Basin locality in Garfield County, northeastern Montana. The material consists of two dentaries, a surangular, and a quadrate from disassociated individuals, which through ontogenetically independent characters allows assignment of the surangular (UCMP 235857) and quadrate (UCMP 235859) to Hadrosaurinae and the dentary (UCMP 235860) to Edmontosaurus. Since Edmontosaurus annectens is the only known hadrosaurid in the formation, we hypothesize that these specimens represent the earliest ontogenetic growth stage of E. annectens providing a significant ontogenetic extension when assessing aspects of cranial ontogeny in this taxon. Using the newly...

First record of a leatherback sea turtle (Dermochelyidae) from the Mio-Pliocene Purisima Formation of northern California, USA

Tue, 25 Jun 2019 00:00:00 +0000
The leatherback sea turtle family Dermochelyidae has an extensive evolutionary history, though it is represented by only one living species today, Dermochelys coriacea. Dermochelyid fossils occur worldwide from upper Cretaceous to Pliocene marine strata. Herein described is the first occurrence of a sea turtle from the lowermost Pliocene Purisima Formation of northern California, a single carapacial non-ridge ossicle. The ossicle exhibits external morphological and internal structural characteristics (ossicle thickness, internal layering, serrate margins) that are comparable to both the extinct genus Psephophorus and to the extant genus Dermochelys. Identification of the ossicle as cf. Psephophorus is based on examination of its thickness, internal structure, surface textures and geochronological age. This paper reports the third occurrence of leatherback sea turtle fossils from the western coast of the United States.

The middle Miocene in southern California: Mammals, environments, and tectonics of the Barstow, Crowder, and Cajon Valley formations—Field Trip of the North American Paleontological Convention, June 22, 2019

Thu, 20 Jun 2019 00:00:00 +0000
The Mojave Region preserves a rich and continuous Miocene mammal-fossil record that formed during a time of significant tectonic activity and climate change. We will visit exposures of the Crowder, Cajon Valley, and Barstow formations to look at the evolution of three different sedimentary basins through the middle Miocene. Participants will learn how depositional environments and habitats changed through time in relation to tectonics and climate and how they influenced patterns of mammal diversity and biostratigraphy.

11th North American Paleontological Conference Program with Abstracts

Wed, 19 Jun 2019 00:00:00 +0000
Program and Abstract volume for the 11th North American Paleontological Conference, June 23-27, 2019, Riverside, CA.

Ediacaran-Cambrian transition of the Southwestern USA—Field Trip of the North American Paleontological Convention, June 19–22, 2019

Sat, 8 Jun 2019 00:00:00 +0000
Participants should plan to arrive in Riverside by June 18. We will depart from the University of California, Riverside campus the morning of June 19. We will drive 5 hours to the White-Inyo Mountains. We will spend the remainder of June 19 and most of June 20 visiting the upper Ediacaran through lower Cambrian succession of this area, including a rich assemblage of trace fossils and some of the earliest Laurentian biomineralized fossils. We will drive to Beatty, NV the evening of June 20. On the morning of June 21, we will visit upper Ediacaran strata and an Ediacaran-Cambrian boundary section of the Reed Dolomite and Deep Spring Formation at Mount Dunfee and see Ediacaran microbialites, tubular body fossils and some of the oldest complex trace fossils. We will spend midday at the nearby ghost town of Gold Point, NV, and have an opportunity to see the spectacular early Cambrian archaeocyathan reefs of the Poleta Formation at Stewart’s Mill in the afternoon. We will depart Beatty...

Late Eocene (Priabonian) elasmobranchs from the Dry Branch Formation (Barnwell Group) of Aiken County, South Carolina, USA

Tue, 4 Jun 2019 00:00:00 +0000
A survey of the Eocene (Priabonian) Dry Branch Formation exposed in Aiken County, South Carolina, resulted in the collection of thousands of fossil teeth and bone fragments. Two sites located near the city of Aiken proved to be particularly productive, and 24 species of elasmobranchs, 11 osteichthyans, and three reptiles (one crocodilian and two turtles) have been identified. Herein we focus on the elasmobranch species (17 sharks and seven rays) that are part of the assemblage, which includes a new species of daggernose shark, Isogomphodon aikenensis n. sp. Cicimurri and Knight. The fossils are derived from the upper part of the Dry Branch Formation, and the fossiliferous strata accumulated within a high energy nearshore marine depositional environment that was influenced by a river system. Based on the vertebrate and invertebrate fossils we identified, the water depth was less than 40 m, and surface water temperature was at least 22° C . Elasmobranch species composition...

Revision of Eocene warm-water cassid gastropods from coastal southwestern North America: implications for paleobiogeographic distribution and faunal-turnover

Tue, 16 Apr 2019 00:00:00 +0000
The warm-water (thermophilic) Eocene cassid gastropods reported previously from coastal southwestern North America (CSWNA), a region extending from the Olympic Peninsula, Washington to Baja California Sur, Mexico, are revised in terms of taxonomy, description, geographic distribution, and biostratigraphy. Five species of the cassine Galeodea and a single species of the phaliine Echinophoria are recognized. Galeodea meganosensis, G. sutterensis, G. louella, G. californica and G. tuberculiformis are predominantly found in California and, collectively, range in age from early to middle Eocene. Echinophoria trituberculata of middle Eocene age in southern California and of earliest late Eocene age in southwestern Washington, is the earliest known record of this genus. Several poorly known supposed cassids are discussed. The pre-Oligocene global record of Galeodea is compiled for the first time. The first...

Puercolestes and Betonnia (Cimolestidae, Mammalia) from the early Paleocene (Puercan 3 Interval Zone) of northeastern Montana, U.S.A.

Fri, 8 Feb 2019 00:00:00 +0000
In northeastern Montana, fossil localities in the Garbani Channel Complex and other early Paleocene (Puercan 3 Interval Zone) localities are preserved in the Tullock Member of the Fort Union Formation. They document an early phase in the recovery of the terrestrial fauna of the North American Western Interior after the mass extinction marking the Cretaceous-Paleogene (K-Pg) boundary. The cimolestids Puercolestes simpsoni and Betonnia tsosia were typified on fragmentary jaws and isolated teeth found in Puercan 2 and 3 Interval Zones (Pu2, Pu3) in the Nacimiento Formation, San Juan Basin, New Mexico. The available samples of these genera from both New Mexico and Montana are small and dominantly consist of isolated teeth. Characters of upper cheek teeth, P4 and M1–M3, justify provisional recognition of Puercolestes sp. cf. Pu. simpsoni and the somewhat smaller Betonnia sp. cf. Be. tsosia in Pu3 local faunas in the Tullock Member....

Insights into cranial morphology and intraspecific variation from a new subadult specimen of the pan-cheloniid turtle Euclastes wielandi Hay, 1908

Mon, 24 Dec 2018 00:00:00 +0000
We describe a nearly complete skull and mandible of a subadult of Euclastes wielandi, a pan-cheloniid turtle recently recovered at the Jean and Ric Edelman Fossil Park at Rowan University in Mantua Township, New Jersey, which yields new information about the osteology, ontogeny, and intraspecific variation of this taxon. The specimen was collected from the earliest Danian Main Fossiliferous Layer (MFL) of the Hornerstown Formation. Although discovered immediately adjacent to remains of two pleurodires, Taphrosphys sulcatus and Bothremys sp., the skull and mandible can be definitively assigned to Pan-Cheloniidae based on its V-shaped basisphenoid and rod-like rostrum basisphenoidale. Among three pan-cheloniid taxa known from the MFL, the specimen is assigned to Eu. wielandi based on its low skull with dorsally-directed orbits, symphyseal swelling in the mandibular triturating surface, and high dorsum sellae. Comparisons with other specimens of...

A new record of Dromomeron romeri Irmis et al., 2007 (Lagerpetidae) from the Chinle Formation of Arizona, U.S.A.

Sat, 22 Dec 2018 00:00:00 +0000
The relatively recent discovery and contextualization of silesaurid and lagerpetid dinosauromorphs has led to a revolution in understanding the early evolutionary history of the dinosaurian lineage. Lagerpetids are known from North America and South America in Middle and Upper Triassic rocks, especially the Chinle Formation of New Mexico and the Dockum Group of Texas. Until now, only a single specimen of Dromomeron gregorii was known from the Upper Triassic Chinle Formation of Arizona. However, a new lagerpetid astragalus specimen (MNA V7237) from the Owl Rock Member of the Chinle Formation found on Ward Terrace in the Navajo Nation of Arizona is referred to Dromomeron romeri. MNA V7237 represents the youngest radioisotopically-dated record of Lagerpetidae, indicating that D. romeri persisted throughout the entire Norian (Otischalkian into the Apachean) in North America.

Using machine learning to classify extant apes and interpret the dental morphology of the chimpanzee-human last common ancestor

Fri, 24 Aug 2018 00:00:00 +0000
Machine learning is a formidable tool for pattern recognition in large datasets. We developed and expanded on these methods, applying machine learning pattern recognition to a problem in paleoanthropology and evolution. For decades, paleontologists have used the chimpanzee as a model for the chimpanzee-human last common ancestor (LCA) because they are our closest living primate relative. Using a large sample of extant and extinct primates, we tested the hypothesis that machine learning methods can accurately classify extant apes based on dental data. We then used this classification tool to observe the affinities between extant apes and Miocene hominoids. We assessed the discrimination accuracy of supervised learning algorithms when tasked with the classification of extant apes (n=175), using three types of data from the postcanine dentition: linear, 2-dimensional, and the morphological output of two genetic patterning mechanisms that are independent of body size: molar module...

Late Cretaceous endemic shallow-marine gastropod genera of the northeast Pacific: biodiversity and faunal changes

Wed, 22 Aug 2018 00:00:00 +0000
Endemic genera of shallow-marine gastropods in the Cretaceous Northeast Pacific Subprovince (NEP), extending from Alaska to northern Baja California Sur, Mexico, are tabulated and discussed in detail for the first time. None are known in Lower Cretaceous or Cenomanian strata, but 43 genera, nearly two-thirds of which are neogastropods, are recognized in Upper Cretaceous strata. Their first appearance was at the beginning of the Turonian, which coincided with the warmest time of the Cretaceous and one of its highest sea-level stands. Fourteen new subtropical endemic genera appeared then, and 10 (71%) were neogastropods. Tethyan-influenced thermophilic mollusks (nerineid, acteonellid, neritid, and cypraeoidean gastropods, as well as rudistid bivalves) were present. A turnover at the Turonian/Coniacian boundary occurred when cooler waters migrated southward, resulting in the subtropical endemics being abruptly and nearly completely replaced by 10 warm-temperate new endemic neogastropods,...

New insights into Late Triassic dinosauromorph-bearing assemblages from Texas using apomorphy-based identifications

Sat, 21 Jul 2018 00:00:00 +0000
The Upper Triassic Dockum Group of Garza County, Texas (lower, middle, and upper Cooper Canyon Formation) captures the radiation of Triassic non-marine tetrapods by preserving a variety of Late Triassic taxa from the southwestern United States. Our understanding of the vertebrate assemblage from these strata largely comes from a single site, the Post Quarry (lower Cooper Canyon Formation), with previous research documenting a variety of temnospondyls, sphenodontians, non-archosauriform archosauromorphs, and archosauriforms including a phytosaur, three species of aetosaurs, a poposauroid, a rauisuchid, a crocodylomorph, and several dinosauromorphs. To more completely reconstruct the vertebrate assemblage of the Dockum Group of Garza County we use an apomorphy-based approach to identify morphologically similar disarticulated and fragmentary elements from a variety of localities that span the entire Cooper Canyon Formation (Norian-Rhaetian), allowing assignments from the large clade...

A new Calliovarica species (Seguenzioidea: Chilodontidae) from the Eocene of Oregon, USA: Persistence of a relict Mesozoic gastropod group in a unique forearc tectonic setting

Wed, 18 Apr 2018 00:00:00 +0000
A new, enigmatic chilodontid gastropod with distinctive periodic varices is described as Calliovarica oregonensis. It is based on ten specimens from slope deposits of the early late Eocene Nestucca Formation on the coastal Cascadia margin of present day Oregon, U.S.A. It is the last appearance of a Mesozoic group of epifaunal basal gastropods with periodic varices. It is the third species in a Cenozoic genus previously known only from the early Eocene Lodo Formation in California and the late Paleocene to early Eocene Red Bluff Tuff in New Zealand. The type species, C. eocensis, is refigured to clarify the nature of the axial varices as well as a terminal thickening and flaring of the apertural lip immediately following deposition of the final varix. Detailed preservation of microstructure in the nacreous layers of crushed and disintegrating shell fragments demonstrates the value of collecting material typically left behind in the field. Calliovarica oregonensis...

Western Association of Vertebrate Paleontologists Annual Meeting

Tue, 20 Mar 2018 00:00:00 +0000
The 2018 Program with Abstracts volume for the Western Association of Vertebrate Paleontologists 52nd Annual Meeting held at Dixie State University, St. George, Utah, USA.

The fauna and chronostratigraphy of the middle Miocene Mascall type area, John Day Basin, Oregon, USA

Mon, 15 Jan 2018 00:00:00 +0000
The Mascall fauna is a well-known middle Miocene (Barstovian) mammalian assemblage in the Pacific Northwest. It has been collected for over 100 years and collecting intensity has increased since the establishment in 1975 of a national monument enclosing the type area of the formation. Despite its importance to biostratigraphy, biogeography of Barstovian taxa, and paleoecological studies, the fauna at the type locality has not been taxonomically examined in more than 50 years. Evaluation and classification of the stratigraphy of the Mascall Formation (Bestland et al. 2008) has prompted a faunal revision in order to place taxa within the new stratigraphic framework. Here we report on the fauna from the type area of the Mascall Formation in central Oregon, and conclude that 20 taxa are new to the fauna, and several taxa previously assigned to distinct species are synonymized. We also place specimens and taxa within a robust stratigraphic framework, calibrated with new U-Pb radioisotopic...

The first report of Toxochelys latiremis Cope, 1873 (Testudines: Panchelonioidea) from the early Campanian of Alabama, USA

Fri, 12 Jan 2018 00:00:00 +0000
Toxochelys latiremis Cope, 1873 is currently thought to be one of the oldest members of the clade originating from the last common ancestor of all extant species of marine-adapted turtles (Chelonioidea). Fossil material of this species has been reported from numerous lower Campanian marine formations across North America; however, reported occurrences have been conspicuously absent from the upper Santonian-to-lower Campanian Mooreville Chalk of Alabama and Mississippi, USA, the type stratum for the only other valid species within the genus, Toxochelys moorevillensis Zangerl, 1953. The apparent absence of T. latiremis from the Mooreville Chalk, and from the southern expanse of the Mississippi Embayment, has made T. latiremis one of the few outliers in previously proposed paleobiogeographic models for marine turtles in the Late Cretaceous Western Interior Seaway. This absence also confounded attempts at reconciling the distribution and phylogeny...

Cenozoic Marine Formations of Washington and Oregon: an annotated catalogue

Fri, 12 Jan 2018 00:00:00 +0000
An annotated list of Cenozoic, fossiliferous marine formations from western Oregon and Washington State, U.S.A., and southwestern Vancouver Island, British Columbia, Canada, has been assembled. This chart is a product of the Eastern Pacific Invertebrate Communities of the Cenozoic (EPICC) Thematic Collections Network project that is digitizing over 1.6 million Cenozoic marine invertebrate fossils from the eastern Pacific margin (Alaska to Chile) housed in the network’s museums. The chart includes formation names currently recognized by Geolex, the U.S. Geological Survey’s National Geologic Map Database. Also included on the chart are prior names, original authors, biozonations, ages from the International Chronostratigraphic Chart (ICC), and references for the most recent age calls.

A juvenile of the multiple-tooth-rowed reptile Labidosaurikos (Eureptilia, Captorhinidae, Moradisaurinae) from the Lower Permian of north-central Texas

Thu, 20 Jul 2017 00:00:00 +0000
Harvard University Museum of Comparative Zoology (MCZ) 1352 is a partial maxillary toothplate of a basal reptilian from the Lower Permian of Baylor County, north-central Texas. The specimen displays the straight rows of teeth characteristic of the subfamily Moradisaurinae (family: Captorhinidae) and is nearly identical in shape to the maxilla of Labidosaurikos meachami. Larger, more mesial individual teeth conform to the dental pattern previously determined for adults of the genus. Adults of L. meachami are known to possess six maxillary tooth rows, whereas MCZ 1352 has only five. Although only a partial specimen, it appears MCZ 1352 is most likely a juvenile specimen of L. meachmi. If correct, the comparative sizes suggest isometric growth of this element. The orientation of the lingual-most row of teeth, and the five as opposed to six maxillary tooth rows, suggest either new tooth rows may move labially during development or bone growth and remodeling...

A new Early Pliocene record of the toothless walrus Valenictus (Carnivora, Odobenidae) from the Purisima Formation of Northern California

Thu, 15 Jun 2017 00:00:00 +0000
The walrus (Odobenus rosmarus) is a large tusked molluskivore that inhabits the Arctic and is the sole living member of the family Odobenidae. In contrast to the modern walrus, extinct walruses lived in temperate and even subtropical climates as far south as Baja California and Japan in the Pacific, and Florida and Morocco in the Atlantic. Multispecies walrus assemblages are now documented from several localities in the North Pacific, the center of origin for the family. The genus Valenictus is a toothless dense-boned walrus reported from several localities in southern California and Baja California. An isolated astragalus from lower Pliocene (5.33–4.89 Ma, Zanclean correlative) sediments of the Purisima Formation of northern California (Santa Cruz County, California) matches the highly derived morphology of Valenictus chulavistensis, and is identifiable as Valenictus sp. This specimen is the first record of Valenictus from the Purisima...

Procerberus (Cimolestidae, Mammalia) from the Latest Cretaceous and Earliest Paleocene of the Northern Western Interior, USA

Tue, 11 Apr 2017 00:00:00 +0000
Three species of the cimolestid Procerberus are currently recognized in the northern North American Western Interior in latest Cretaceous and earliest Paleocene (Puercan North American Land Mammal Age) faunas: P. formicarum, P. andesiticus, and P. grandis. Analysis of a new topotypic sample of P. formicarum from the Bug Creek Anthills locality provides an estimate of the range of variation of its postcanine dentition. The three currently recognized species occur in Puercan 1 (Pu1) interval zone faunas, but two other occurrences indicate that the genus originated and initially diversified prior to the Cretaceous/Paleogene boundary. Rare occurrences at several localities and entries in faunal lists suggest even greater taxonomic diversity. Limited evidence suggests continued diversification in the later Puercan and possible survival of the genus into the Torrejonian. Procerberus grandis or a closely related species may be a sister...

Western Association of Vertebrate Paleontology Annual Meeting: Program with Abstracts

Mon, 27 Feb 2017 00:00:00 +0000
The Program and Abstracts volume for the 2017 WAVP annual meeting held February 17-19, 2017 at Yavapai College, Prescott, Arizona.

New theropod fossils from the Upper Triassic Dockum Group of Texas, USA, and a brief overview of the Dockum theropod diversity

Wed, 1 Feb 2017 00:00:00 +0000
New records enrich the Late Triassic theropod assemblage of the Dockum Group of Texas. Here, five unpublished theropod specimens (TTU-P11175, TTU-P12531X, TTU-P12587X, TTU-P14786, TTU-P16789) are described, each represented by a single element and collected from various fossil localities of Garza County, Texas. Additionally, two previously described specimens (TTU-P10082, TTU-P10534), which were also recovered from Upper Triassic rocks of Garza County are revisited for additional remarks on their anatomy. These new theropod specimens increase the abundance and disparity of theropods in the Dockum terrestrial vertebrate fauna. Together, with confirmed theropod discoveries in other recent works, the newly evaluated specimens add to the long history of dinosaur research in the Dockum Group of Texas.

The age of the Oso Member, Capistrano Formation, and a review of fossil crocodylians from California

Mon, 30 Jan 2017 00:00:00 +0000
Fossils from the late Miocene Oso Member of the Capistrano Formation in Orange County, California, are underreported in the scientific literature. Mitigation activities in the Oso Member have resulted in collections of fossils in museums. We provide a preliminary list of identified faunal elements from the Oso Member and determine its age using biostratigraphy. The presence of the fossil horse Dinohippus interpolatus allows us to constrain the age of the Oso Member to the early late Hemphillian (Hh3, 6.6–5.8 Ma). We provide a review of other Hemphillian terrestrial vertebrate sites from Southern California. Our age assessment for the Oso Member allowed us to recognize a significant temporal range extension for crocodylians on the Pacific Coast of the United States. Including the Oso Member, the fossil record of crocodylians in California is based on fragmentary material from 13 formations ranging from the Paleocene to the late Miocene (including seven Eocene units). Of...

The giant, spike-toothed salmon, Oncorhynchus rastrosus and the “Proto-Tuolumne River” (early Pliocene) of Central California

Mon, 14 Nov 2016 00:00:00 +0000
Oncorhynchus rastrosus was a very large, spike-toothed, Pacific Salmon from the mid-Miocene to early Pliocene of the Pacific Northwest (California to Washington). It had two large premaxillary (breeding-fighting) teeth that stuck out laterally from the snout like spikes. It migrated from the Pacific Ocean to inland rivers to spawn, as extant Pacific salmon do today. It was planktivorous, based on numerous, long, over-lapping gill-rakers, and few, small teeth. There are gaps in our knowledge about this interesting salmon. First, one of the localities where many of the paratype specimens were collected (Turlock Lake, California), was not described geologically in the original paper beyond, ‘from the Mehrten Formation’. Here we describe these deposits as cross-bedded sands, gravels and large, rounded cobbles indicative of a fast-flowing, river, which we coin here as the “proto-Tuolumne River,” that periodically overflowed its banks. Paleocurrent directions indicate the river...

A lower jaw of the nautiloid Aturia angustata (Conrad, 1849) from Oligocene cold seep limestone, Washington State, U.S.A.

Mon, 17 Oct 2016 00:00:00 +0000
Fossil shells of the extinct nautiloid genus Aturia have been found in Cenozoic strata in many parts of the world, and yet there have only been two previous records of fossils of any part of the jaw apparatus of Aturia. This suggests that the jaws were only preserved by virtue of special, highly localized conditions. A fossilized lower jaw referable to Aturia has been found in western Washington State, USA, associated with two shells of Aturia angustata within a piece of limestone that formed as a result of localized hydrocarbon seepage on the deep-sea floor. This is the first report of a nautiloid jaw from Cenozoic strata of western North America, and the first report of any part of the jaw apparatus for A. angustata.

First record of the megatoothed shark Carcharocles megalodon from the Mio-Pliocene Purisima Formation of Northern California.

Tue, 16 Aug 2016 00:00:00 +0000
Megatoothed sharks (Family: Otodontidae) are among the most widely reported sharks in Cenozoic marine sediments worldwide, and certain species such as the famed Carcharocles megalodon are particularly abundant in Neogene deposits on the Atlantic margin of the United States. Cenozoic marine strata on the Pacific margin of North America have yielded one of the most densely sampled marine vertebrate records anywhere, but published occurrences of shark assemblages are uncommon. Rarer yet are published occurrences of C. megalodon from this region with unambiguous provenance and robust age control — critical data required for the study of recent marine vertebrate faunal evolution in the eastern North Pacific. A tooth of C. megalodon from near Santa Cruz, California, represents the first record of this species from the Purisima Formation and the geochronologically youngest occurrence (6.9–5.6 Ma, uppermost Miocene; late Messinian) of this species from northern...

Pleistocene vertebrates of Silicon Valley (Santa Clara County, California)

Fri, 22 Jul 2016 00:00:00 +0000
Here we report on late Pleistocene fossil vertebrates from new and previously described localities in Santa Clara County, California. The three new localities and specimens include: a partial mammoth pelvis from UCMP V91128 (Lawrence Expressway E); a juvenile cranial specimen of Mammuthus columbi from UCMP V99597 (SCVWD “Lupe” Mammoth), now on display at the San Jose Children’s Discovery Center; and a relatively diverse assemblage of medium- to large-sized mammals, including a nearly complete forelimb of Paramylodon harlani from UCMP V99891 (Babcock’s Bones). We also reassess specimens and assemblages from the following eight previously known localities: Molecular Medicine Building (UCMP V90003); Alma Street Underpass at Page Mill Road (USGS M1203); Mountain View Dump (USGS M1227); Sunnyvale Sewer (USGS M1218); Calabaza, Sunnyvale Sewer (USGS M1218A); Matadero Creek (USGS M1001); Matadero Creek, Veteran’s Hospital (USGS M1202); and Milpitas (UCMP V4916). All...

Fauna and setting of the Adelolophus hutchisoni type locality in the Upper Cretaceous (Campanian) Wahweap Formation of Utah

Thu, 9 Jun 2016 00:00:00 +0000
We report new data on the type locality of the hadrosaurid ornithischian Adelolophus hutchisoni Gates et al., 2014 from the Campanian-aged Wahweap Formation of southern Utah, and the remainder of the vertebrate assemblage from the site. The type locality (UCMP V98173) is a previously-reported U.S. Geological Survey locality (USGS D815) and is stratigraphically low in the upper member of the Wahweap Formation. Additional taxa from the same site include acipenseriforms (sturgeon), amiiforms (bowfin), and lepisosteiforms (gar fish), baenid and trionychid turtles, and both theropod and ornithischian dinosaurs.

Yelmochelys rosarioae gen. et sp. nov., a stem kinosternid (Testudines; Kinosternidae) from the Late Cretaceous of Coahuila, Mexico

Wed, 13 Apr 2016 00:00:00 +0000

A small smooth-shelled kinosternoid from the late Campanian Cerro del Pueblo Formation and the early Maastrichtian Canyon del Tule Formation of Coahuila, Mexico that is abundantly represented by isolated elements is described as Yelmochelys rosarioae gen. et sp. nov. A phylogenetic analysis concludes that Y. rosarioae is a representative of the stem lineage of the Kinosternidae. Inclusion of Y. rosarioae in Kinosternidae is supported by presence of a groove for the musk duct, the loss of the eleventh peripheral and twelfth marginal, reduced articulation between the plastron and carapace, and diamond-shaped vertebral scales. A basal position within Kinosternidae is indicated by the presence of distinct abdominal scales that meet at the midline and the presence of a relatively long costiform processes. The inclusion of Y. rosarioae in Kinosternidae supports the hypothesis that Kinosternidae and Dermatemydidae had diverged by the Late Campanian.

A fossil giant tortoise from the Mehrten Formation of Northern California

Tue, 8 Mar 2016 00:00:00 +0000

Hesperotestudo is a genus of giant tortoise that existed from the Oligocene to the Pleistocene of North and Central America. Recorded occurrences in the United States are plentiful; however, California seems to be an exception. Literature on Hesperotestudo in California is limited to faunal lists in papers, with few detailed descriptions. Here we review the literature on the genus, describe and identify specimens found in the upper Mehrten Formation (late Miocene-early Pliocene) exposed in the Central Valley of California at Turlock and Modesto Reservoirs, Stanislaus County, and address their implications for early Pliocene California biogeography and climate. All fossils described are from the collections of the University of California Museum of Paleontology (UCMP). The largest specimen from the Mehrten is a peripheral from an animal with an estimated carapace length over one meter. The specimens were compared first to modern material of Gopherus,...

Western Association of Vertebrate Paleontology Annual Meeting: Program with Abstracts

Thu, 11 Feb 2016 00:00:00 +0000
Abstracts and program for the February 13-14, 2016, WAVP Annual Meeting, Anza-Borrego Desert State Park, Borrego Springs, CA, USA.

Early Eocene (Wasatchian) rodent assemblages from the Washakie Basin, Wyoming

Mon, 8 Feb 2016 00:00:00 +0000
Rodent assemblages are described from two early Eocene (Wasatchian North American Land Mammal Age; Graybullian subage) localities from the Main Body of the Wasatch Formation in the Washakie Basin, Wyoming. One locality (UCMP V71237) represents a catastrophic death assemblage and the other (UCMP V71238) is a channel lag which immediately overlies it. Quarrying and screen-washing at these localities has resulted in the recovery of 81 specimens from V71237 and 224 specimens from V71238 and comprising a uniquely rich, stratigraphically controlled sample. The rodent fauna from these localities include Paramys copei, P. taurus, Lophiparamys murinus, Microparamys hunterae, Tuscahomys ctenodactylops, and Knightomys cf. K. minor. These specimens provide substantial new morphological data for the previously poorly-known M. hunterae, T. ctenodactylops, and L. murinus. Comparison of relative abundances demonstrates that T. ctenodactylops is the most common in both localities, but that the...

Materials collected by the southern branch of the UC Africa Expedition with a report on previously unpublished Plio-Pleistocene fossil localities

Tue, 1 Dec 2015 00:00:00 +0000

From 1947 to 1948, paleontologists from the University of California Museum of Paleontology (UCMP), Charles Camp and Frank Peabody, led the southern branch of the University of California’s Africa Expedition. While in South Africa, Camp and Peabody collected thousands of specimens excavated from more than 70 sites, 40 of which make up the Plio-Pleistocene South African assemblage at the UCMP. Materials collected by researchers accompanying the expedition are held at numerous repositories on the University of California Berkeley campus including the UCMP, the Museum of Vertebrate Zoology (MVZ), the Phoebe A. Hearst Museum of Anthropology and the University of California’s Botanical Gardens.
In 2013, we curated the Plio-Pleistocene paleontological assemblage of the UCMP South Africa collection and cataloged 5,082 specimens from four primary areas: Bolt’s Farm, Buxton Limeworks, Gladysvale and Witkrans. Both invertebrates and vertebrates are found in the South African assemblage,...

Paleogene marine bivalves of the deep-water Keasey Formation in Oregon, Part III: The heteroconchs

Fri, 2 Oct 2015 00:00:00 +0000

The heteroconch bivalve fauna of the deep-water (>200 m) Keasey Formation in northwestern Oregon records the Eocene–Oligocene climatic transition and replacement of tropical widely-distributed taxa by the cryophilic taxa that dominate modern high-latitude faunas of the North Pacific. Low-diversity assemblages occur in tuffaceous mudstone and siltstone facies of a deep nearshore basin at the onset of subduction on the Cascadia Margin. Six species of anomalodesmatan heteroconchs have been treated separately, and the remaining Keasey heteroconchs treated here include one basal archiheterodont and 13 imparidentian euheterodonts. The families represented are Carditidae, Thyasiridae, Lucinidae, Lasaeidae, Cardiidae, Tellinidae, Basterotiidae, Mactridae and Veneridae. New taxa include the genus Anechinocardium and seven new species: Cyclocardia moniligena, Conchocele bathyaulax, Conchocele taylori, Kellia saxiriva, Kellia vokesi,...

Oldest known marine turtle? A new protostegid from the Lower Cretaceous of Colombia

Mon, 7 Sep 2015 00:00:00 +0000

Recent studies suggested that many fossil marine turtles might not be closely related to extant marine turtles (Chelonioidea). The uncertainty surrounding the origin and phylogenetic position of fossil marine turtles impacts our understanding of turtle evolution and complicates our attempts to develop and justify fossil calibrations for molecular divergence dating. Here we present the description and phylogenetic analysis of a new fossil marine turtle from the Lower Cretaceous (upper Barremian-lower Aptian, >120 Ma) of Colombia that has a minimum age that is >25 million years older than the minimum age of the previously recognized oldest chelonioid. This new fossil taxon, Desmatochelys padillai sp. nov., is represented by a nearly complete skeleton, four additional skulls with articulated lower jaws, and two partial shells. The description of this new taxon provides an excellent opportunity to explore unresolved questions about the antiquity and content of Chelonioidea....

Paleocene chimaeroid fishes (Chondrichthyes: Holocephali) from the eastern United States, including two new species of Callorhinchus

Fri, 10 Jul 2015 00:00:00 +0000

Isolated tooth plates collected from Paleocene deposits of Alabama, Arkansas, Illinois, Maryland, Mississippi, New Jersey, South Carolina, Texas, and Virginia represent four genera of chimaeroid fishes. Callorhinchus is reported in the fossil record of North America for the first time and is represented by material from the Danian (early Paleocene) of Mississippi and the Thanetian (late Paleocene) of Maryland and Virginia. Specimens from both locations are identified as new species, the Danian C. phillipsi n. sp. and the Thanetian C. alfordi n. sp. New Paleocene Elasmodus records from North America include two partial mandibulars belonging to E. hunteri from the Thanetian of Maryland, and a nearly complete mandibular from the Danian of New Jersey, tentatively assigned to cf. Elasmodus sp. Two species of Ischyodus are recognized, I. dolloi (Danian and Thanetian) and I. williamsae (Danian), but the...

Western Association of Vertebrate Paleontology Annual Meeting: Program with Abstracts

Tue, 20 Jan 2015 00:00:00 +0000
Abstracts and program for the February 14-15, 2015, WAVP Annual Meeting, California State University, Stanislaus, Turlock, CA, USA.

Prodiacodon crustulum (Leptictidae, Mammalia) from the Tullock Member of the Fort Union Formation, Garfield and McCone Counties, Montana, USA

Fri, 9 Jan 2015 00:00:00 +0000
Since Michael J. Novacek (1977) established Prodiacodon crustulum, the hypodigm of this species has been greatly increased. Currently, over 100 isolated teeth, but only a single dentulous fragment of a dentary, are known. Reconstruction of its dentition has been based on comparisons with the more completely represented dentition of P. puercensis Matthew, 1929, from younger Torrejonian 1-3 North American Land Mammal Age (NALMA) local faunas of the San Juan Basin, New Mexico. Prodiacodon crustulum is known from the Puercan 3 (NALMA) Garbani Channel and, possibly, Purgatory Hill local faunas in Montana. It differs from P. puercensis in the smaller size of its postcanine dentition and lesser development of minor cusps on the upper and lower molars. Given the uncertainties in reconstruction of its dentition, the new sample adds little toward illustrating the phylogenetic relationships of the species to more recent Paleogene and Neogene leptictids....

Paleogene marine bivalves of the deep-water Keasey Formation in Oregon, part IV: The anomalodesmatans

Tue, 16 Dec 2014 00:00:00 +0000
The late Eocene–early Oligocene Keasey Formation in Northwestern Oregon contains a unique fauna of deep-water (>200 m) marine bivalves preserved in sparsely fossiliferous massive tuffaceous siltstone as well as in several distinctive cold-seep limestone bodies and carbonate layers. The Keasey gastropod fauna has been described previously, but this treatment of the anomalodesmatan bivalves is the first systematic account for any portion of the bivalve fauna. Cenozoic evolutionary radiation and history of anomalodesmatans is less well known than their deep Paleozoic and Mesozoic history. Because internal relationships are not well resolved, ranked classification is not used above the family level, while recognizing that these rare and unusual bivalves do represent a monophyletic assemblage nested within the basal heterodonts. Six species in four anomalodesmatan families in the Keasey Formation shed new light on the Cenozoic history of the group as well as the Eocene appearance...

Modularity and sexual dimorphism in human metacarpals

Tue, 9 Dec 2014 00:00:00 +0000

The shape of an animal’s hands provides insight not only to its locomotory habitus but can also reveal information about the genetic and developmental sources that underlie its variation. Detailed analyses of skeletal shape variation within a population can test hypotheses about the genetic, nongenetic, and epigenetic sources underlying that variation. Here, we report on the variation, patterns of correlation, and sexual dimorphism of human metacarpal size in order to better understand the evolutionary history of the hominid hand. Seven linear measurements were collected from unaffiliated adult Native Californians that lived between 3050 BP and 150 BP, correlations across digits were estimated and compared for the entire population, and for males and females. We also assessed sexual dimorphism in variance as well as for metacarpal length ratios.
Results indicate the thumb, or pollical metacarpal (MC1) measurements are only weakly correlated with those of the index through...

Late Cretaceous chimaeroids (Chondrichthyes: Holocephali) from Alabama, USA

Mon, 16 Jun 2014 00:00:00 +0000
Tooth plates of three extinct species of callorhynchid holocephalans, Edaphodon mirificus, E. barberi, and Ischyodus bifurcatus have been collected from Upper Cretaceous strata of Alabama. Of the two species of Edaphodon, E. mirificus is represented by isolated tooth plates as well as associated dentitions. Edaphodon barberi was based on a small left mandibular tooth plate, but additional mandibular tooth plates in museum collections show that the diagnostic features seen on the E. barberi holotype are consistently present and therefore useful for species differentiation. Ischyodus bifurcatus is reported for the first time in Alabama and is known from a partial associated dentition and several isolated tooth plates. Most of the fossils are from the upper Santonian to lower Campanian Mooreville Chalk, but two specimens of Edaphodon from a lower Campanian component of the Tombigbee Sand Member of the...

Paleogene chelonians from Maryland and Virginia

Tue, 27 May 2014 00:00:00 +0000
Fossil remains of 22 kinds of Paleogene turtles have been recovered in Maryland and Virginia from the early Paleocene Brightseat Formation (four taxa), late Paleocene Aquia Formation (nine taxa), early Eocene Nanjemoy Formation (five taxa), middle Eocene Piney Point Formation (one taxon), and mid-Oligocene Old Church Formation (three taxa). Twelve taxa are clearly marine forms, of which ten are pancheloniids (Ashleychelys palmeri, Carolinochelys wilsoni, Catapleura coatesi, Catapleura sp., Euclastes roundsi, E. wielandi, ?Lophochelys sp., Procolpochelys charlestonensis, Puppigerus camperi, and Tasbacka ruhoffi), and two are dermochelyids (Eosphargis insularis and cf. Eosphargis gigas). Eight taxa represent fluvial or terrestrial forms (Adocus sp., Judithemys kranzi n. sp., Planetochelys savoiei, cf. “Trionyx” halophilus, “Trionyx”...

A lithornithid (Aves: Palaeognathae) from the Paleocene (Tiffanian) of southern California

Tue, 13 May 2014 00:00:00 +0000
The proximal end of a bird humerus recovered from the Paleocene Goler Formation of southern California is the oldest Cenozoic record of this clade from the west coast of North America. The fossil is characterized by a relatively large, dorsally-positioned head of the humerus and a subcircular opening to the pneumotricipital fossa, consistent with the Lithornithidae among known North American Paleocene birds, and is similar in size to Lithornis celetius. This specimen from the Tiffanian NALMA extends the known geographic range of lithornithids outside of the Rocky Mountains region in the United States. The inferred coastal depositional environment of the Goler Formation is consistent with a broad ecological niche of lithornithids. The age and geographic distribution of lithornithids in North America and Europe suggests these birds dispersed from North America to Europe in the Paleocene or by the early Eocene. During the Paleogene the intercontinental dispersal of lithornithids...

Middle Eocene trees of the Clarno Petrified Forest, John Day Fossil Beds National Monument, Oregon

Mon, 28 Apr 2014 00:00:00 +0000
One of the iconic fossils of the John Day Fossil Beds National Monument, Oregon, USA, is the Hancock Tree—a permineralized standing tree stump about 0.5 m in diameter and 2.5 m in height, embedded in a lahar of the Clarno Formation of middle Eocene age. We examined the wood anatomy of this stump, together with other permineralized woods and leaf impressions from the same stratigraphic level, to gain an understanding of the vegetation intercepted by the lahar. Wood of the Hancock Tree is characterized by narrow and numerous vessels, exclusively scalariform perforation plates, exclusively uniseriate rays, and diffuse axial parenchyma. These features and the type of vessel-ray parenchyma indicate affinities with the Hamamelidaceae, with closest similarity to the Exbucklandoideae, which is today native to Southeast and East Asia. The Hancock Tree is but one of at least 48 trees entombed in the same mudflow; 14 others have anatomy similar to the Hancock Tree; 20 have anatomy similar...

Bonnima sp. (Trilobita; Corynexochida) from the Chambless Limestone (Lower Cambrian) of the Marble Mountains, California: First Dorypygidae in a cratonic region of the southern Cordillera

Tue, 18 Mar 2014 00:00:00 +0000
A trilobite pygidium, likely referable to the genus Bonnima, is the first evidence of a member of the Corynexochida reported from the Lower Cambrian (Dyeran Stage) Chambless Limestone of the southern Marble Mountains in the Mojave Desert of California. This specimen represents the first occurrence of the family Dorypygidae in the cratonic facies of the Lower Cambrian in the California-western Nevada region, as all of the few previous reports of the family (mostly Bonnia) have been from much thicker, more distal open-shelf deposits far to the northwest in the White-Inyo—Esmeralda County region of California and Nevada. Although still relatively rare, the occurrence of Dorypygidae across a range of environments biofacies realms in this area is typical of their distribution in other regions.

New record of an extinct fish, Fisherichthys folmeri Weems (Osteichthyes), from the lower Eocene of Berkeley County, South Carolina, USA

Tue, 18 Mar 2014 00:00:00 +0000

Fisherichthys folmeri Weems 1999 (Sciaenidae?) is an extinct teleostean fish occurring in marine strata of the Gulf and Atlantic coastal plains, USA. We report isolated teeth collected from a lower Eocene (Ypresian) deposit in Berkeley County, South Carolina. Crowns of unworn teeth bear apical papillae surrounding a central depression, but these features are lost as teeth are worn through in vivo usage. The pulp cavity appears to become reduced in size as the tooth matures in the alveolus. Fisherichthys folmeri is thus far only known from Mississippi, South Carolina, and Virginia in strata ranging in age from 50.8 to 55 Ma.

The skull of Postosuchus kirkpatricki (Archosauria: Paracrocodyliformes) from the Upper Triassic of the United States

Tue, 18 Mar 2014 00:00:00 +0000

The skull of Postosuchus kirkpatricki Chatterjee 1985 is known from the holotype and paratype specimens along with disassociated skull elements from several Triassic localities in the southwestern and eastern United States. Recent preparation of the holotype skull allows for more careful examination of the cranial elements and comparison with related taxa. This description indicates that Postosuchus shares several previously unrecognized synapomorphies with crocodylomorphs, including fossae and foramina in the dermatocranium that are not present in other basal pseudosuchians. The sutural arrangements of the skull of Postosuchus presented in this paper differ considerably from previous descriptions, due in part to the reassignment of what was previously considered the prefrontal to the palpebral bone. Also, further preparation of skull elements revealed morphologies that differ from previous descriptions. This new description also indicates a close...

The earliest North American record of the Antilocapridae (Artiodactyla, Mammalia)

Tue, 18 Mar 2014 00:00:00 +0000

The Family Antilocapridae is considered to have first appeared in the Early Hemingfordian of western North America. Here we report a mandible of a merycodontine antilocaprid from the Late Arikareean Harrison Formation of eastern Wyoming. The mandible has three lower molars preserved and mandibular ramus features that allow it to be differentiated from other contemporaneous selenodont artiodactyl families, yet the lack of detailed understanding of intraspecific variation in Paracosoryx and Merycodus warrant caution in assigning this to a genus. This new material predates the previous first appearance of antilocaprids by approximately 3–4 million years and suggests that antilocaprid immigration from Eurasian ruminant stock occurred earlier than previously assumed and that caution should be exercised when using first appearances in broader analyses.

New soft-shelled turtles (Plastomeninae, Trionychidae, Testudines) from the Late Cretaceous and Paleocene of North America

Tue, 18 Mar 2014 00:00:00 +0000

Two new genera (Derrisemys and Plastomenoides) and three new species (D. sterea, P. lamberti, P. tetanetron) of plastomenine trionychids from Montana and Wyoming are described. They are unique within the Trionychidae in having the entoplastron locked into notches in the hyoplastra and restricting midline kinesis. D. sterea occurs in the Lancian NALMA (North American Land Mammal Age) of Montana and Wyoming and Puercan NALMA of Montana. P. tetanetron occurs in the Puercan NALMA of Montana. P. lamberti occurs in the Torrejonian NALMA of Montana and Tiffanian NALMA of Wyoming and Utah. Plastomenus acupictus Hay 1907 from New Mexico is referred to Derrisemys. The age of D. acupictus is uncertain but is likely from early Paleocene (Torrejonian NALMA).

Recent ucmp_paleobios items

Paleobiology Database User Guide Version 2.0

New mammalian herbivore records from the Early to Middle Miocene Castilletes fauna, Colombia and late Neogene environmental change in northern South America

Newly described specimens of leptarctine mustelids expand their geographic range in the western United States

2025 Western Association of Vertebrate Paleontology Annual Meeting Abstracts

New species of the deep-water bivalve genera Acesta (Limidae, Bivalvia, Mollusca) and a questionable Malletia (Malletiidae, Bivalvia, Mollusca) from the Eocene of southern California

Paleogene marine bivalves of the deep-water Keasey Formation in Oregon, Part IA: The protobranchs (Nuculidae, Sareptidae, Pristiglomidae)

Western Association of Vertebrate Paleontology Annual Meeting Abstracts PaleoBios 42(2):1-12

Multiple geniculated types in a single inoceramid (Bivalvia) species: “Inoceramus” nebrascensis

Fossil leaves, fruits and seeds of the Late Eocene Teater Road flora near Post, Oregon, USA

Temporalis attachment area as a proxy for feeding ecology in toothed whales (Artiodactyla: Odontoceti)

Reptiles from the late Eocene Jackson Group of Arkansas

Geology, microstratigraphy, and paleontology of the lacustrine Truckee Formation diatomite deposits near Hazen, Nevada, USA, with emphasis on fossil stickleback fish

A late Eocene wood assemblage from the Crooked River Basin, Oregon, USA

Two new plioplatecarpine mosasaurs (Mosasauridae; Plioplatecarpinae) of the genus Ectenosaurus from the Upper Cretaceous of North America

A new aetosaur (Archosauria: Pseudosuchia) from the upper Blue Mesa Member (Adamanian: Early–Mid Norian) of the Late Triassic Chinle Formation, northern Arizona, USA, and a review of the paratypothoracin Tecovasuchus across the southwestern USA

2023 Western Association of Vertebrate Paleontology Annual Meeting: Program with Abstracts

Paleogene marine bivalves of the deep-water Keasey Formation in Oregon, Part II: The pteriomorphs

First Cretaceous teleostean otolith assemblage (Arkadelphia Formation, upper Maastrichtian) from Arkansas, USA, early Gadiformes, and the Western Interior Seaway

Paleobiology Database User Guide Version 1.0

The dentition of the extinct megamouth shark, Megachasma applegatei (Lamniformes: Megachasmidae), from southern California, USA, based on geometric morphometrics

Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U.S.A.

Caecidae (Mollusca: Gastropoda) from late Miocene exposures of the “Imperial” Formation in Riverside County, California

A methane seep from the deep-marine, late Eocene Keasey Formation, Rock Creek, Columbia County, Oregon

A new fossil Euspira? (Mollusca: Gastropoda: Naticidae) from the Gubik Formation on the North Slope of Arctic Alaska

Acanthodian fauna from the Early Devonian (Emsian) of Death Valley, California

Washington State trigoniids (Bivalvia) from the conglomerate of Patterson Lake (Early Cretaceous)

Revision of northeast Pacific Paleogene cypraeoidean gastropods (Mollusca), including recognition of three new species: Implications for paleobiogeographic distribution and faunal turnover

Nucella demouthae, a new Late Miocene muricid gastropod from Northern California, U.S.A.

The extinct limpet Lottia edmitchelli (Lipps, 1963) from the Southern California Bight, U.S.A.

The earliest Ancistrolepis (Gastropoda: Buccinidae) and its geologic implications

Early Oligocene (Rupelian) fishes (Chondrichthyes, Osteichthyes) from the Ashley Formation (Cooper Group) of South Carolina, USA

First record of the chancelloriid Allonnia from the middle Cambrian Wheeler Formation (Drumian, Miaolingian) of western Utah

Arcoid bivalve biodiversity during Eocene doubthouse cooling: Contrasting the active Cascadia Margin coldspot with the intracratonic Paris Basin hotspot

Reconstructing oyster paleocommunity structure over the last 3.6 million years: A southern California case study

The first in situ collection of a mosasaurine from the marine Breien Member of the Hell Creek Formation in south-central North Dakota, USA

New proboscidean material from the Siwalik Group of Pakistan with remarks on some species

The first records of Sinclairella (Apatemyidae) from the Pacific Northwest, USA

Taphonomic bias in collections of horse phalanges from the Barstow Formation (Miocene) and Rancho La Brea (Pleistocene) of California, USA

Califrapana: a new genus of California and Bája California late Oligocene to early Miocene muricids previously attributed to the genus Rapana (Mollusca: Gastropoda: Muricidae)

New remains of middle Miocene equids from the Cajon Valley Formation, San Bernardino National Forest, San Bernardino County, California, USA

Checklist of California Paleogene–Neogene marine Mollusca since Keen and Bentson (1944)

New dinosauromorph specimens from Petrified Forest National Park and a global biostratigraphic review of Triassic dinosauromorph body fossils

First description of the fossil otolith-based sciaenid, Equetulus silverdalensis n. comb., in the Gulf Coastal Plain, USA, with comments on the enigmatic distribution of the species

Faunal change in Cretaceous endemic shallow-marine bivalve genera/subgenera of the northeast Pacific

A new Lyropecten (Pectinidae, Bivalvia, Mollusca) from the central California Miocene, USA

Epiplastral and geographic variation in Echmatemys, a geoemydid turtle from the Eocene of North America: A multi-tiered analysis of epiplastral shape complexity

Two new Miocene limpets (Fissurellidae) from southern California, with notes on other fossil occurrences of the family in northwestern North America

A new drepanosauromorph, Ancistronychus paradoxus n. gen. et sp., from the Chinle Formation of Petrified Forest National Park, Arizona, USA

A protocol for differentiating late Quaternary leporids in southern California with remarks on Project 23 lagomorphs at Rancho La Brea, Los Angeles, California, USA

Miocene marine macropaleontology of the fourth bore Caldecott Tunnel excavation, Berkeley Hills, Oakland, California, USA

Nestling-sized hadrosaurine cranial material from the Hell Creek Formation of northeastern Montana, USA, with an analysis of cranial ontogeny in Edmontosaurus annectens

First record of a leatherback sea turtle (Dermochelyidae) from the Mio-Pliocene Purisima Formation of northern California, USA

The middle Miocene in southern California: Mammals, environments, and tectonics of the Barstow, Crowder, and Cajon Valley formations—Field Trip of the North American Paleontological Convention, June 22, 2019

11th North American Paleontological Conference Program with Abstracts

Ediacaran-Cambrian transition of the Southwestern USA—Field Trip of the North American Paleontological Convention, June 19–22, 2019

Late Eocene (Priabonian) elasmobranchs from the Dry Branch Formation (Barnwell Group) of Aiken County, South Carolina, USA

Revision of Eocene warm-water cassid gastropods from coastal southwestern North America: implications for paleobiogeographic distribution and faunal-turnover

Puercolestes and Betonnia (Cimolestidae, Mammalia) from the early Paleocene (Puercan 3 Interval Zone) of northeastern Montana, U.S.A.

Insights into cranial morphology and intraspecific variation from a new subadult specimen of the pan-cheloniid turtle Euclastes wielandi Hay, 1908

A new record of Dromomeron romeri Irmis et al., 2007 (Lagerpetidae) from the Chinle Formation of Arizona, U.S.A.

Using machine learning to classify extant apes and interpret the dental morphology of the chimpanzee-human last common ancestor

Late Cretaceous endemic shallow-marine gastropod genera of the northeast Pacific: biodiversity and faunal changes

New insights into Late Triassic dinosauromorph-bearing assemblages from Texas using apomorphy-based identifications

A new Calliovarica species (Seguenzioidea: Chilodontidae) from the Eocene of Oregon, USA: Persistence of a relict Mesozoic gastropod group in a unique forearc tectonic setting

Western Association of Vertebrate Paleontologists Annual Meeting

The fauna and chronostratigraphy of the middle Miocene Mascall type area, John Day Basin, Oregon, USA

The first report of Toxochelys latiremis Cope, 1873 (Testudines: Panchelonioidea) from the early Campanian of Alabama, USA

Cenozoic Marine Formations of Washington and Oregon: an annotated catalogue

A juvenile of the multiple-tooth-rowed reptile Labidosaurikos (Eureptilia, Captorhinidae, Moradisaurinae) from the Lower Permian of north-central Texas

A new Early Pliocene record of the toothless walrus Valenictus (Carnivora, Odobenidae) from the Purisima Formation of Northern California

Procerberus (Cimolestidae, Mammalia) from the Latest Cretaceous and Earliest Paleocene of the Northern Western Interior, USA

Western Association of Vertebrate Paleontology Annual Meeting: Program with Abstracts

New theropod fossils from the Upper Triassic Dockum Group of Texas, USA, and a brief overview of the Dockum theropod diversity

The age of the Oso Member, Capistrano Formation, and a review of fossil crocodylians from California

The giant, spike-toothed salmon, Oncorhynchus rastrosus and the “Proto-Tuolumne River” (early Pliocene) of Central California

A lower jaw of the nautiloid Aturia angustata (Conrad, 1849) from Oligocene cold seep limestone, Washington State, U.S.A.

First record of the megatoothed shark Carcharocles megalodon from the Mio-Pliocene Purisima Formation of Northern California.

Pleistocene vertebrates of Silicon Valley (Santa Clara County, California)

Fauna and setting of the Adelolophus hutchisoni type locality in the Upper Cretaceous (Campanian) Wahweap Formation of Utah