title: Understanding the formation of ancient intertropical disjunct distributions using Asian and Neotropical hinged-teeth snakes (Sibynophis and Scaphiodontophis: Serpentes: Colubridae).
abstract: Numerous taxa show ancient intertropical disjunct distributions. Many can be explained by well-known processes of historical vicariance, such as the breakup of Gondwanaland. Others, such as Asian-Neotropical divergences are not as well understood. To clarify the phylogenetic position and understand biogeographic and temporal origins of the geographically disjunct and morphologically unique genera of hinged-teeth snakes, Scaphiodontophis (n=1) and Sibynophis (n=9; Colubridae), we inferred a time-calibrated phylogeny with additional 107 taxa representing the superfamily Colubroidea using four genes (c-mos, cyt-b, ND2, RAG-1; 3085 bp). We used this tree to estimate ancestral areas for the group. The results show that Scaphiodontophis is sister to Sibynophis, both originated in the late Eocene/Oligocene in Asia and likely dispersed through Beringia to the New World, but unlike other snake groups left no extant species in temperate North America. Current recognition of Scaphiodontophiinae renders Colubrinae paraphyletic, and we resurrect the previously named subfamily Sibynophiinae to encompass both genera and use the tribes Sibynophiini (Sibynophis) and Scaphiodontophiini (Scaphiodontophis) to highlight the geographically distinct areas occupied by these taxa. These results suggest that intercontinental dispersal with extinction in intermediate areas can explain puzzling patterns of ancient intertropical disjunct distributions.
authors.affiliation: Department of Biology, The College of Staten Island, The City University of New York, 2800 Victory Blvd., Staten Island, NY 10314, United States. xchen1@gc.cuny.edu
authors.forename: Xin
authors.initials: X
authors.lastname: Chen
authors.forename: Song
authors.initials: S
authors.lastname: Huang
authors.forename: Peng
authors.initials: P
authors.lastname: Guo
authors.forename: Guarino R
authors.initials: GR
authors.lastname: Colli
authors.forename: Adrián
authors.initials: A
authors.lastname: Nieto Montes de Oca
authors.forename: Laurie J
authors.initials: LJ
authors.lastname: Vitt
authors.forename: R Alexander
authors.initials: RA
authors.lastname: Pyron
authors.forename: Frank T
authors.initials: FT
authors.lastname: Burbrink
mesh_terms: D063147:Animal Distribution; D000818:Animals; D001499:Bayes Theorem; D002467:Cell Nucleus / Q000235:genetics; D017812:Colubridae / Q000145:classification* / Q000235:genetics; D004272:DNA, Mitochondrial / Q000235:genetics; D019143:Evolution, Molecular; D005843:Geography; D016013:Likelihood Functions; D008957:Models, Genetic; D010802:Phylogeny; D017422:Sequence Analysis, DNA
chemical_list: D004272:DNA, Mitochondrial