A New Species of Snake in the Genus Contia (Squamata: Colubridae) from California and Oregon

We describe Contia longicaudae, a new colubroid snake from California and Oregon, USA. Because C. longicaudae differs only subtly from the nominate species, C. tenuis, it has long been overlooked. However, genetic and morphological data readily distinguish C. longicaudae as distinct from C. tenuis. Contia longicaudae is genetically cohesive, possesses a greater number of caudal scales, a proportionately longer tail, and tends to be larger overall with more pronounced dorso-lateral stripes and a more muted ventral coloration than C. tenuis. Contia longicaudae also occurs in more mesic and well-shaded habitats than C. tenuis. Both forms appear to be broadly parapatric throughout much of northwestern California, and a few areas of sympatry have already been identified, particularly in southwestern Oregon, but the two species have not yet been found syntopically. Our data also reveal additional structure within C. tenuis; populations from the southern Sierra Nevada Mountains form an incipient lineage that warrants further investigation. The genetic and morphological subdivisions identified here allow future evolutionary and ecological studies, and conservations efforts, to focus on distinct evolutionary units within Contia.

Fig. 1

Distribution of C. longicaudae (black triangles) and C. tenuis (gray circles) in California, Oregon, Washington, and British Columbia, based on museum specimens and literature accounts (Hoyer et al., 2006; O'Donnell and McCutchen, 2008; Sharp-tailed Snake Recovery Team, 2008). The type locality of C. longicaudae (white triangle) is in Mendocino Co., CA, and that of C. tenuis (white circle) in Pierce Co., WA (Leonard and Ovaska, 1998). Inset maps highlight regions in Oregon and coastal California where the two species come into close proximity.

Fig. 2

Plots of individual samples on the two principle components axes (A, B) and two canonical variates axes (C, D), derived from morphological measurements (log₁₀ transformed) of male and female C. longicaudae (black triangles) and C. tenuis (gray circles).

Fig. 3

Phylogenetic relationships within Contia. (A) Combined analysis of mtDNA and nuDNA sequences based on Maximum Parsimony (MP) and Bayesian (BI) methods recover two lineages: C. longicaudae (black); C. tenuis (gray). Nodal support is given by BI posterior probabilities (above node), and MP bootstrap percentages and decay indices (below node). Sample number and county given for each individual; sample numbers on trees correspond to localities on map (see Material Examined); note sample 23 is the type specimen of C. longicaudae (CAS 231505). The same two major clades are recovered in separate analyses of mtDNA (B) and nuDNA (C) data; mean pairwise, uncorrected genetic distances reported between and within Contia species for both mtDNA and nuDNA.

Fig. 4

Contia longicaudae, holotype, CAS 231505, female. (A) Dorsal and (B) ventral views. Photographs by J. V. Vindum.

Contributor Notes

Associate Editor: D. Kizirian.

¹ Department of Natural Resources and Environmental Science, University of Nevada Reno, Reno, Nevada 89557, E-mail: ophis@cabnr.unr.edu. Send reprint requests to this address.

² 2121 North West Mulkey Avenue, Corvallis, Oregon 97330.

Received: 10 Jul 2009

Accepted: 11 Nov 2009