Museum of Texas Tech University

About: Museum of Texas Tech University is a based out in . It is known for research contribution in the topics: Phylogenetic tree & Cytochrome b. The organization has 66 authors who have published 193 publications receiving 4860 citations.

Molecular phylogenetics of the neotoma floridana species group

Abstract: Phylogenetic relationships among 4 subspecies of Neotoma floridana and sister species from the United States and Mexico were examined using DNA sequence data from the mitochondrial DNA cytochrome b gene. Parsimony, likelihood, and neighbor-joining analyses support the recognition of N. f. magister as a distinct species (N. magister). Populations of eastern woodrats from the southern and western United States also possessed relatively high levels of sequence divergence (5.3%), which may be indicative of ongoing divergence between these populations. These findings support conclusions from previous studies and add clarity to the biogeographic processes influencing evolution and diversification of this group of rodents.

Diet and Habitat for Six American Pleistocene Proboscidean Species Using Carbon and Oxygen Stable Isotopes

Abstract: . Diet and habitat were estimated, based on stable isotopes, for six species of proboscideans inhabiting the Americas during the Pleistocene. In North America, Mammuthus columbi (Elephantidae) was a mixed C3/C4 herbivore inhabiting open areas, while Mammut americanum (Mammutidae) fed exclusively on C3 plants and preferred closed areas. In contrast, members of the family Gomphotheriidae showed a wide range of food preference and habitats. This is the case of Cuvieronius tropicus, a mixed-diet herbivore living in open areas. In South America, another gomphothere — Cuvieronius hyodon — inhabited open areas and had a C3-plant diet similar to others from some Southern plains such as Stegomastodon platensis. On the other hand, S. waringi from tropical South America lived in open areas and had a C3/C4 mixed diet. The fact that gomphotheres had more flexible diet habits could explain why those animals were able to cross the Panamanian Isthmus, while mammoths and mastodons did not.

A new aetosaur from the Upper Triassic Chinle Formation of the Eagle Basin, Colorado, USA

Abstract: Abstract A small aetosaur skull and skeleton and referred material from the Chinle Formation, Eagle Basin of Colorado, USA, is described as a new taxon, Stenomyti huangae gen. et sp. nov, distinguished from other aetosaurs by the following autapomorphies: three premaxillary teeth; four palpebrals; pronounced midline ridge on frontals and parietals; paired ridges flanking midline ridge on parietal and frontal; exclusion of quadratojugal from ventral margin of skull by contact between jugal and quadrate; exclusion of postorbital from infratemporal fenestra; infratemporal fenestra a horizontally oriented oval that embays the posterior edge of the jugal; retroarticular process longer than distance between articular glenoid and posterior edge of external mandibular fenestra; oval to irregularly shaped ventral osteoderms that do not contact each other. Paramedian and lateral osteoderms of S. huangae are nearly identical to those of Aetosaurus ferratus, and other shared cranial characters suggest that these taxa are closely related and lie outside the clade Typothoracisinae + Desmatosuchinae. This discovery indicates that other reports of Aetosaurus across Laurasia based on osteoderms should be reassessed. Similar confusion with the osteoderms of other non-typothoracisine/desmatosuchine aetosaurs such as Aetosauroides, Stagonolepis and Calyptosuchus suggests that osteoderms are not always reliable taxonomic indicators.

New information for systematics, taxonomy, and phylogeography of the rodent genus apodemus (sylvaemus) in ukraine

Abstract: ?In 2004, we collected 211 specimens of European field mice (genus Apodemus; subgenus Sylvaemus) from 16 localities in northern, western, central, and southern Ukraine, including the Crimean Peninsula. We used cytochrome-b mitochondrial DNA sequence data to investigate species diversity, distributional patterns, and taxonomy of Apodemus in Ukraine. Sequence data proved useful for species-level discrimination, because the 11 species examined were defined by low levels of intraspecific variation (mean range, 0.00‐3.35%) and by high levels of interspecific variation (mean range, 5.37‐18.9%). We identified the 211 specimens to 1 of 4 species: A. flavicollis (n ¼ 121), A. sylvaticus (n ¼ 34), A. uralensis (n ¼ 16), and A. witherbyi (n ¼ 40). Although all 4 species are known from Ukraine, this study provides new information about the ranges and population identity for these species in southeastern Europe. For example, our analyses substantiate the marked genetic structure reported for A. sylvaticus and document the presence of northern and southern continental lineages of this species in Ukraine that are hypothesized to have been isolated from each other in glacial refugia approximately 1.5 million years ago (.5% genetic divergence). Banks of the Dneiper River in northern Ukraine represent an area of secondary contact for the 2 lineages. Additionally, although application of A. witherbyi as a species-level name is debatable, examination of our genetic and morphological data supports its validity and priority over junior synonyms A. hermonensis and A. iconicus.