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 systematics of neotomine–peromyscine rodents based on the dentin matrix protein 1 gene

Abstract: Despite previous work on the North American sigmodontine rodents, phylogenetic relationships within the neotomine–peromyscine complex remain conjectural. The debate focuses not only on the number of tribes within the group, but also on the relationships of genera within each tribe. Phylogenetic relationships of 19 species representing 13 genera of neotomine–peromyscine rodents were examined by using approximately 1,200 base pairs (bp) of exon 6 of the nuclear, protein-coding dentin matrix protein 1 gene (Dmp1). The topology obtained from the maximum likelihood analysis indicated that 4 tribes should be recognized: the Neotomini, Peromyscini, Baiomyini, and Tylomyini, with the Tylomyini sister to a rapidly radiating clade of neotomine–peromyscine–baiomyine rodents. In addition, it appears that Dmp1 is phylogenetically informative at the tribal level in North American sigmodontine rodents.

Geochronology and Landscape Development Along the Middle Río Quequén Grande at the Paso Otero Locality, Pampa Interserrana, Argentina

Abstract: The Paso Otero Locality is a cluster of archaeological sites within the middle Rio Quequen Grande basin located in the northern coastal plain of Argentina. The valley fill is Holocene alluvial, eolian, and palustrine sediment, including the top of the Guerrero Member (∼10,000 14C yr B.P.), upper Rio Salado Member (∼3000 14C yr B.P.), and lower La Postrera Formation (∼2400 14C yr B.P.). Regional soils include the Puesto Callejon Viejo (10,000 to 9400 14C yr B.P.) and the Puesto Berrondo (∼4800 14C yr B.P.). Radiocarbon sampling of buried A-horizons on both sides of the river produced 17 dates considered reliable. The geoarchaeological information allows exploration of the implications for the formation of the archaeological record. Similar geological processes of differential intensity have resulted in contexts of different archaeological resolution and integrity. The Paso Otero Locality provides both a local and regional view of late Quaternary events and processes for the middle basin of the Rio Quequen Grande.

Hybrid Zones, Genetic Isolation, and Systematics of Pocket Gophers (Genus Geomys) in Nebraska

Abstract: Pocket gophers of the genus Geomys are common inhabitants of many habitats throughout most of the state of Nebraska. Because the taxonomic history of Geomys has undergone numerous changes through the years, these pocket gophers have been the subjects of ongoing taxonomic and distributional studies and in more recent years genetic studies to understand relationships among populations. In order to gain deeper insight into the relationships among these taxa of Geomys, we intensively collected specimens from areas where chromosomal races were thought to form contact zones. Results from examination of genetic (chromosomes, mitochondrial cytochrome-b gene sequences, and nuclear interphotoreceptor retinoid-binding protein gene sequences), morphometric, and pelage coloration data revealed 2 areas of hybridization between taxa of Geomys in Nebraska. The 1st of these corresponded to the Oakdale vicinity in Antelope and Madison counties in northeastern Nebraska and the 2nd corresponded to Lincoln County in southwestern Nebraska. The taxonomic implications of our study support the recommendations from earlier studies performed in other areas of the geographic range of Geomys. Specifically, in Nebraska we recognize 3 species: G. bursarius majusculus in eastern Nebraska, G. lutescens in the Sand Hills and adjacent areas of central and western Nebraska, and G. jugossicularis halli in southwestern Nebraska. The exact geographic distributions and relationships of these species within Nebraska and the surrounding states remain to be determined in detail.

Patterns of Secondary Sexual Size Dimorphism in New World Myotis and a Test of Rensch's Rule

Abstract: For bats, when secondary sexual dimorphism is significant, females typically are larger than males. Moreover, in mammals, variation in the degree of sexual dimorphism often follows an allometric relationship whereby differences vary with body size (Rensch's rule). We examined sexual dimorphism across the New World clade of Myotis regarding species-specific and clade-wide patterns of body, cranium, and wing size, Rensch's rule and degree to which such morphological variation is related to phylogeny. Size differences were common with significant cases of both male-biased and female-biased sexual dimorphism. In more than half the cases, females were larger than males. Variation in degree of dimorphism exhibited an allometric pattern. Nonetheless, slope of the relationship between size and degree of dimorphism was no different from unity (i.e., isometry), failing to support Rensch's rule. There was a strong and significant relationship between phylogeny and morphological variation but not between phylogeny an...

New World proboscidean extinctions: comparisons between North and South America

Abstract: In South America, generally accepted dates place humans in coastal Chile and Patagonia ca. 13,000 BP and sites no older than ca. 11,000 BP are common in other areas. Gomphotheres become extinct in the late Pleistocene, probably after humans arrived and as climate changed. However, bone dates suggest that in many regions of South America, especially the Pampean region of Argentina and Uruguay (ca. 21,000 to 18,000 BP), gomphotheres already were gone when the first humans arrived. Although gomphothere remains are present at Monte Verde and other sites, they do not appear to have been important for human subsistence. In North America, human presence also is accepted around 11,500 BP. Gomphotheres range throughout much of Mexico into the US Southwest. Very few places are known with dated Quaternary gomphotheres, and most of them are considered paleontological localities rather than archeological sites. A small number of reliable associations between Clovis artifacts and proboscideans correspond to Mammuthus and Mammut remains. Controversial human evidence has been proposed for Valsequillo (Puebla, Mexico), where gomphotheres coexisted with mammoth and mastodons. Recent findings in northern Sonora, on more secure grounds, point to a human–gomphothere relationship around 11,000 BP. No human–gomphothere association is documented in the USA. Gomphotheres apparently survive until the end of the Pleistocene, but certainly those survivors were unique relict populations. Gomphothere extinction is driven more by climate and ecosystem changes than through human interactions.