Phylogeny and biogeography of the West Indian xenodontine snakes: A biochemical perspective

Date of Award




Degree Name

Doctor of Philosophy (Ph.D.)



First Committee Member

Jay M. Savage - Committee Chair


The West Indian assemblage of xenodontine (Colubridae) snakes was phylogenetically evaluated with allozyme data and restriction site data of the ribosomal DNA repeat. To assess mainland relationships, 24 xenodontine taxa from Central, South and North America were included with the 18 Antillean taxa. A natricine, Nerodia fasciata, was included and employed as the outgroup in the initial analyses. Outgroup substitution was used to determine proper outgroups and evaluate hypotheses of monophyly. Allozyme data were collected for all taxa and resulted in 20 informative characters. The ribosomal DNA data were collected for 16 taxa and proved uninformative at a higher taxonomic level. Cladistic analysis revealed four separate lineages in the West Indies with South, Central and North American affinities. Alsophis, Ialtris, and perhaps Hypsirhynchus form Group I, which is related to two relict lineages, Farancia (NA) and Manolepis (SA). Uromacer and the Puerto Rican and Cuban Arrhyton form Group II and are the sister group to the enigmatic Central American Amastridium. Group III includes the Jamaican Arrhyton and the monotypic genus Darlingtonia and has no obvious mainland relationship. Antillophis parvifrons is the sister taxon to a clade of four mainland taxa, Conophis lineatus (CA), Tretanorhinus nigroluteus (CA), Sibon nebulata (CA) and Saphenophis sneideri (SA). A descriptive historical biogeographic analysis of area cladograms suggests a moderately diverse xenodontine snake fauna was present during the Eocene and provided stock groups for the current Antillean fauna. The radiation represents distinct time periods that incorporate both dispersal and vicariance events. In general the Antillean xenodontine snakes follow vicariance models previously proposed for the Antillean biota, except for Jamaica which was probably populated via dispersal.


Biology, Zoology

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