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.
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.
Volume 29, Issue 3, 2010
Studies have used cell size as a proxy to estimate polyploidy levels, the number of chromosome sets in somatic cells, in modern and fossil plant species. This paper critically evaluates these methods by reviewing cell size- and polyploidy-related literature, and provides new cell size data from herbarium material and fossil remains of willow genus Salix. The 40 extant taxa used in the study include most of the polyploidy levels encountered in Salix (2n = 38, 76, 114, 152, 190). Diploid and tetraploid species were morphologically similar to the fossil specimens. Specimens from alpine and arctic regions, forms rarely found in the fossil record, were included to extend the range of polyploidy levels. Measurements taken for this study were on the petiole epidermal cells of fossil and herbarium specimens and the stomatal guard cell complexes of herbarium material. A literature review reveals cell size may not relate only to DNA content, but to a plant’s age, nutritional state and the seasonal timing of organ development. Cell size measurements show that cultivated plants grown at elevations more than 800 m below their original place of growth have a significant increase in cell size. Leaf length-to-width ratio, infrageneric classification, and adaptation to dry or humid environments also correlate with cell size. Cell size proxies for estimating polyploidy levels in fossil willows provide only accurate results if morphologically similar modern plant material from natural habitats is used as a reference for comparison. Leaves should be similar in overall shape, base and apex shape, blade length and width, length-to-width ratio, petiole length, petiole-to-blade length ratio, venation pattern, and margin dentition.
A Machairodont felid (Mammalia; Carnivora; Felidae) from the latest Hemphillian (Late Miocene/Early Pliocene) Bidahochi Formation, northeastern Arizona
A lower jaw from the White Cone local fauna of the latest Hemphillian Bidahochi Formation in northern Arizona is the first description of a felid from this fauna and the first positively identified occurrence of the smilodontine machairodont Paramachairodus in North America. This lower jaw has characters identical to those seen in a similar sized machairodont felid from the Bone Valley Formation of Florida, suggesting that the same taxon is present in Florida. The diversity of the Hemphillian machairodonts and the taxonomic status of Megantereon hesperus is reviewed. The characteristics of the ramus corpus and dentition places Paramachairodus firmly within the Smilodontini and adds further support that the more derived smilodontine machairodonts, Megantereon and Smilodon, had their origins in North America.