Mitochondrial Dna Phylogeography of the Polytypic North American Rat Snake (Elaphe Obsoleta): A Critique of the Subspecies Concept

Abstract

Subspecies have been considered artificial subdivisions of species, pattern classes, or incipient species. However, with more data and modern phylogenetic techniques, some subspecies may be found to represent true species. Mitochondrial DNA analysis of the polytypic snake, Elaphe obsoleta, yields well-supported clades that do not conform to any of the currently accepted subspecies. Complete nucleotide sequences of the cytochrome b gene and the mitochondrial control region produced robust maximum-parsimony and maximum-likelihood trees that do not differ statistically. Both trees were significantly shorter than a most parsimonious tree in which each subspecies was constrained to be monophyletic. Thus, the subspecies of E. obsoleta do not represent distinct genetic lineages. Instead, the evidence points to three well-supported mitochondrial DNA clades confined to particular geographic areas in the eastern United States. This research underscores the potential problems of recognizing subspecies based on one or a few characters.

Molecular Systematics, Phylogeography, and the Effects of Pleistocene Glaciation in the Painted Turtle (Chrysemys Picta) Complex

“…A similar conclusion has been reached over the last decade for several ectothermic vertebrates, including the tiger salamander complex (Shaffer and McKnight 1996), the leopard frog complex (Hillis 1988), the gopher snake Pituophis (Rodriguez-Robles and De Jesus-Escobar 2000), and the black rat snake complex (Burbrink et al 2000). Unlike these other recent studies, our mtDNA work supports the concept of a continentally distributed species for C. picta (sensu lato), although we feel that C. dorsalis should not be a part of that wide-ranging species.…”

Taxonomic revision of the tigrina Leopardus tigrinus (Schreber, 1775) species group (Carnivora, Felidae)

“…As a result we consider as valid taxa, populations who share unique characters in common, including the variation, and which differ from the other also in the geographic attributes. Subspecies, on the other hand, represent geographical subdivisions of the species and are described mainly based on differences in measurements or difference in the tones of general coloration (Mayr 1942;Bonvicino et al 1989;Burbrink et al 2000;Helgen et al, 2013). The recognition of subspecies was historically based on one or few specimens (e.g., Pocock, 1939Pocock, , 1940Pocock, , 1941aPocock, , 1941bPocock, , 1941cGoldman, 1946;Kitchener & Yamaguchi, 2010), however, studies have demonstrate that to the properly recognition and description of it, a set of characters throughout the range of the species should be carefully evaluated (Mayr, 1942;Burbrink et al, 2000;Helgen et al, 2013), which has never been done for tigrinas until the present study.…”

Out of Asia: Natricine snakes support the Cenozoic Beringian Dispersal Hypothesis

“…The entire gene sequences for the mitochondrial cytochrome b (cyt b) and NADH dehydrogenase subunit 2 (ND2), the partial gene sequences of NADH dehydrogenase subunit 4 (ND4) and one nuclear gene c-mos were amplified by the polymerase chain reaction (PCR) using primers L14910/H16064 (Burbrink et al, 2000), L5238/H5382 (de Queiroz et al, 2002), ND4/Leu (Arèvalo et al, 1994) and S77/S78 (Lawson et al, 2005), respectively. The cycling parameters were identical to those described in above studies.…”