| Summary: | Climate has a profound influence on the distribution of species and changing climate conditions during the Pleistocene epoch, displacing several species from their present day ranges. The Pleistocene epoch began about 2.6 million years ago and lasted until about 11,700 years ago. Of the seven known glacial periods, the last one, known as the Last Glacial Maximum (LGM), ended approximately 25 Kya. In North America, the Laurentide Ice Sheet extended into a major portion of eastern North America, whereas the southern parts were unglaciated. During this time, the climate was drastically different, and much of the deciduous forests in Eastern North America changed into boreal forests. The changing climates, corresponding range shifts and geographic barriers, can promote differentiation due to habitat fragmentation. The genus Carphophis dates back to the mid-late Pliocene (~240 – 11 Kya) and consists of two nominal species C. amoenus (Eastern worm snake) and C. vermis (Western worm snake). The eastern worm snake is further divided into two subspecies, the C. a. amoenus and C. a. helenae (Midwestern worm snake). This study utilizes the mitochondrial cytochrome b gene to investigate the phylogeographic structure and demographic patterns of in the Eastern worm snake. Preliminary results inferred five mitochondrial lineages, which may indicate the underestimation of species diversity. These genetic patterns do not match patterns that are commonly seen in other organisms that are affected by the LGM and provides new insights to potential regions throughout eastern North America.
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