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Full-Text Articles in Life Sciences

Mechanical Properties Of The Integument Of The Common Gartersnake, Thamnophis Sirtalis (Serpentes: Colubridae), Gabriel Rivera Jul 2003

Mechanical Properties Of The Integument Of The Common Gartersnake, Thamnophis Sirtalis (Serpentes: Colubridae), Gabriel Rivera

Biological Sciences Theses & Dissertations

The evolution of the ophidian feeding mechanism has involved substantial morphological restructuring associated with the ability to ingest relatively large prey. Previous studies examining the morphological consequences of macrophagy have concentrated on modifications of the skull and cephalic musculature. Although it is evident that macrophagy requires highly compliant skin, the mechanical properties of the ophidian integument have received limited attention, particularly in the context of feeding. I examined mechanical properties of skin along the body axis in male Thamnophis sirtalis (Colubridae). From each of 11 specimens, I examined nine circumferential strips of skin, each spanning 10 ventral scales, spaced at …


Geographic Variation In The Morphology Of Crotalus Horridus (Serpentes: Viperidae), John Robert Allsteadt Jul 2003

Geographic Variation In The Morphology Of Crotalus Horridus (Serpentes: Viperidae), John Robert Allsteadt

Biological Sciences Theses & Dissertations

The Timber Rattlesnake (Crotalus horridus) occurs in discontinuous populations throughout the eastern and central United States. The species exhibits high levels of polymorphism in morphological traits, especially in coloration and pattern. Previous studies recognized either distinct northern and southern subspecies or three regional morphs (northern, southern, and western), but conflicting data sets and limited geographic sampling of previous studies have left the relationships among those regional variants unclear. In this study, univariate and multivariate statistics, together with a geographic information system, were used to analyze geographic variation in 36 morphological characters recorded from 2,420 specimens of C. horridus …


An Unusually Colored Red-Backed Salamander (Plethodon Cinerus) From Northern Virginia, Joseph C. Mitchell, Thomas K. Pauley, C. Todd Georgel Apr 2003

An Unusually Colored Red-Backed Salamander (Plethodon Cinerus) From Northern Virginia, Joseph C. Mitchell, Thomas K. Pauley, C. Todd Georgel

Virginia Journal of Science

We describe an orange-pink, patternless, translucent morph of the Red-backed Salamander (Plethodon cinereus) found in northern Virginia on 27 September 2001. This is the first description of this unusual phenotype in this terrestrial salamander.


Keys To The Mammals And Mammal Skulls Of The Northern Coastal Plain Of Virginia, John F. Pagels, A. Scott Bellows, Joseph C. Mitchell Apr 2003

Keys To The Mammals And Mammal Skulls Of The Northern Coastal Plain Of Virginia, John F. Pagels, A. Scott Bellows, Joseph C. Mitchell

Virginia Journal of Science

This publication is designed to function as a tool for the identification of mammal species that occur on the Coastal Plain of northern Virginia. We provide whole-body and skull keys to the 40 species that occur in this region. Baseline data for this work were collected during several studies conducted on Fort A.P. Hill, Caroline County. The intended audience includes interested naturalists, teachers, students, field biologists, and natural resource managers.


Hybridization Between The Watersnakes Nerodia Sipedon And Nerodia Fasciata, In The Carolinas: A Morphological And Molecular Approach, Konrad Mebert Apr 2003

Hybridization Between The Watersnakes Nerodia Sipedon And Nerodia Fasciata, In The Carolinas: A Morphological And Molecular Approach, Konrad Mebert

Biological Sciences Theses & Dissertations

A few traditionally applied diagnostic characters of color pattern were compared with an additional set of morphological and genetic characters to evaluate differences between Nerodia sipedon and N. fasciata and to study the dynamics across their hybrid zone in the Carolinas. Many of the morphological characters exhibited significant interspecific differences, although only the number of dorsally complete crossbands (CBa) was diagnostic by itself. A discriminant function analysis of morphological characters was successful in separating both taxa. Species-specific nuclear markers, identified by the AFLP (Amplified Fragment Length Polymorphism) technique were nearly fixed and served as diagnostic markers. They revealed extensive introgression …