Epiplastral shape and geographic variation of Echmatemys from the Eocene of Utah!
Heather F. Smith et al. analyze epiplastral shape and geographic variation in the geoemydid turtle, Echmatemys, from the Eocene Uinta Basin , Utah, USA.
First leatherback sea turtle (family Dermochelyidae) from the Mio-Pliocene Purisima Formation of California!
Bailey Fallon and Bobby Boessenecker describe the first leatherback sea turtle, cf. Psephophorus, from the lower Pliocene Purisima Formation of California, USA.
The Miocene Mascall vertebrate fauna revisited!
An excellent update of the vertebrate fauna and chronostratigraphy of the Miocene type Mascall Formation, John Day Basin, Oregon, USA by Kaitlin Clare Maguire, Joshua Samuels, and Mark Schmitz.
Toxochelys latiremis Cope, 1873
First report of this turtle from the Cretaceous of Alabama, USA by Andrew Gentry and Jun Ebersole.
Program and abstracts for the 52nd annual meeting of the Western Association of Vertebrate Paleontologists held at Dixie State University in St. George, Utah, USA.
Calliovarica oregonensis Hickman
A new species of chilodontid gastropod from the Eocene of Oregon, USA by Carole S. Hickman.
Late Triassic vertebrates from the Dockum Group of Texas!
New apomorphy-based identifications of vertebrates from the Late Triassic Dockum Group of Texas by Lessner et al.
An EPICC contribution!
Annotated list of the Cenozoic marine formations of the Pacific Northwest by Liz Nesbitt.
Use of machine learning to classify extant apes!
Monson et al. apply machine learning using dental morphology to classify extant apes and shed light on the chimpanzee-human last common ancestor.
New subadult skull specimen of Euclastes wielandi Hay, 1908 from the Cretaceous of New Jersey, USA!
New study of a subadult skull by P. Ullmann, Z. Boles and M. Knell provides insights into the cranial morphology and intraspecific variation in the Cretaceous pan-cheloniid turtle Euclastes wielandi.
Cimolestids (Mammalia) from the Paleocene of Montana!
New report on Puercolestes and Betonnia, two cimolestids from the early Paleocene (Puercan) of northeastern Montana, U.S.A. by William A. Clemens.
Eocene cassid gastropods from North America!
A reassessment by Richard Squires of Eocene warm-water cassid gastropods (Family Cassidae) from North America and implications for their paleogeographic distribution and faunal turnover following the Paleocene-Eocene Thermal Maximum.
Late Eocene elasmobranchs from Aiken County, South Carolina, USA!
Cicimurri and Knight describe new material of sharks and rays (elasmobrachs) from the Dry Branch Formation of Aiken County, South Carolina USA.
NAPC 2019 Field trip guide to the Ediacaran-Cambrian transition in the southwestern USA!
Field trip guide to the Ediacaran-Cambrian transition led by E. Smith, L. Tarhan and L. Nelson for the 2019 North American Paleontological Convention (NAPC).
Late Cretaceous endemic shallow-marine gastropods of the northeast Pacific!
Biodiversity and faunal changes in Late Cretaceous northeast Pacific gastropods by Richard L. Squires.
NAPC 2019 field trip guide to the geology and paleontology of Miocene formations in southern California!
Katharine Loughney and Tara Smiley's NAPC 2019 field trip guide to the geology and paleontology of the Miocene Barstow, Crowder, and Cajon Valley formations of southern California.
Program and Abstracts for the 11th North American Paleontological Conference!
Program and Abstracts for the 11th North American Paleontological Conference (NAPC) hosted by University of California, Riverside June 23-27, 2019.
Nestling-sized hadrosaurine crania from the Late Cretaceous of Montana!
Wosik et al. describe new cranial remains of hadrosaurine nestlings from the Late Cretaceous Hell Creek Formation, Montana, USA, with analysis of cranial ontogeny in Edmontosaurus annectens.
Miocene macropaleontology of the Caldecott Tunnel fourth bore excavation, Berkeley Hills, CA, USA!
Powell et al. describe Miocene marine macrofossils recovered from the fourth bore excavation of the Caldecott Tunnel in the Berkeley Hills, Oakland, CA, USA.
New protocol for differentiating leporids from the late Quaternary of southern California, USA!
Fox et al. propose new protocol using dental morphology for identifying late Quaternary leporids from southern California with remarks on lagomorphs from Rancho La Brea's Project 23!
A new drepanosauromorph from the Chinle Formation of Petrified Forest National Park, Arizona, USA!
Gonçalves and Sidor describe the new Triassicdrepanosauromorph genus and species,Ancistronychus paradoxus, from the Chinle Formation of the Petrified Forest National Park, Arizona, USA!
New limpets from the Miocene of southern California, USA!
Charles Powell and Daniel Geiger describe and name two new limpet species, Scelidotoma aldersoni n. sp. and Fissurella? stantoni n. sp. from the Miocene of southern California, USA.
Volume 37, 2020
Epiplastral and geographic variation in Echmatemys, a geoemydid turtle from the Eocene of North America: A multi-tiered analysis of epiplastral shape complexity
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 a methodological question regarding the relative efficacy of data complexity in this context. Using epiplastra from three additional Eocene species of Echmatemys, we employed hierarchical analyses of increasing data complexity, from standard linear dimensions to 2D geometric morphometrics to 3D laser scans, to determine the degree to which data complexity contributes to taxonomic assessments within this genus. Uintan species E. callopyge and E. uintensis were found to differ significantly in epiplastral shape as captured by all three categories of data. These findings verify that these two co-occurring species can be differentiated consistently using the shape of the gular scale, and that the use of geometric morphometrics can improve identification of fragmentary specimens. Among the non-Uintan species, dorsal and ventral 2D landmark data reliably differentiated among species, but the linear dimensions were less useful.
- 2 supplemental files