Presentation Detail

Systematics and Inferred Phylogenies

Reyes-Velasco, Jacobo  [1], Meik, Jesse [2], Smith, Eric [2], Castoe , Todd [2].

Phylogenetic relationships of the enigmatic longtailed rattlesnakes (Crotalus ericsmithi, C. lannomi, and C. stejnegeri).

The longtailed rattlesnakes of western Mexico represent an enigmatic group of three poorly known venomous snake species: Crotalus ericsmithi, C. lannomi, and C. stejnegeri. In the 120 years since their discovery, fewer than twenty individuals have been deposited in natural history collections worldwide. These three species share similar morphological traits, including a particularly long tail that has been interpreted as either an ancestral condition among rattlesnakes or as derived within the longtailed group. An understanding of the phylogenetic distinctiveness and relationships among the longtailed rattlesnakes, and their relationship to other rattlesnake groups, has previously been hampered by a dearth of comparative material and tissues for collection of DNA sequence data. Facilitated by the recent availability of tissue samples from multiple individuals of each species, we here estimate the phylogenetic relationships among the longtailed rattlesnakes and their placement among other rattlesnake groups, using DNA sequence data (including three mitochondrial andthree nuclear gene fragments). We explore phylogenetic signal in our data using concatenated Bayesian and maximum likelihood methods, hypothesis testing, and species tree analyses. Our results strongly support the monophyly of longtailed rattlesnakes and suggest the three species diverged from each other during the mid-Pliocene(ca. 4.4-3.4 mya). Contrary to prevailing hypotheses, we find no evidence for an ancient or basal divergence of the longtailed clade within the rattlesnaketree and instead estimate that it diverged relatively recently (ca. 7.7 mya) from its sister lineage, comprised most likely of the C. viridis and C. atrox groups.

1 - University of Texas at Arlington, Biology, 501 S. Nedderman Drive, 337 Life Science, Arlington, TX, 76010-0498, United States
2 - University of Texas at Arlington, 501 S. Nedderman Drive, 337 Life Science, Arlington, TX, 76010-0498, United States

Keywords:
biogeography
phylogeny
Rattlesnakes 
systematics.

Presentation Type: Regular Oral Presentation
Session: 104
Location: Rendezvous B/Snowbird Center
Date: Monday, June 24th, 2013
Time: 9:00 AM
Number: 104003
Abstract ID:606
Candidate for Awards:Ernst Mayr Award,W.D. Hamilton Award for Outstanding Student Presentation,Student Travel Awards from the ASN