Title

The phylogenetic relationships of the New World coral snakes (Elapidae: Leptomicrurus, Micruroides and Micrurus) based on biochemical and morphological data

Date of Award

1991

Availability

Article

Degree Name

Doctor of Philosophy (Ph.D.)

Department

Biology

First Committee Member

Jay M. Savage, Committee Chair

Abstract

A phylogenetic analysis of the New World coral snakes (Elapidae: Leptomicrurus, Micruroides, and Micrurus) was performed using allozyme and morphological characters. The allozyme data were generated for a subset of the 57 species of coral snakes and two species of Bungarus included as the outgroup. Fourteen loci were satisfactorily resolved for all species; of these, 10 formed informative characters. The morphological characters were divided among osteological, hemipenial, venom gland, and scutellation characters. Exteme morphological conservatism was found and only 9 morphological characters were informative. It was possible to score all 57 species for the morphological characters.Two matrices were constructed: one containing only those species included in the electrophoretic analysis and an expanded matrix including all species. Twenty-four shortest trees resulted from a parsimony analysis of the reduced matrix, each 48 steps long with a consistency index (CI) of 0.864. Strict (SCT) and semistrict consensus trees were generated from the 24 shortest trees. Analysis of the expanded matrix resulted in several thousand shortest trees, each 46 steps long and with a CI of 0.870. The SCT generated from these trees represents a general hypothesis of the phylogenetic relationships of coral snakes.The results of this study indicate that Micruroides is the sister-taxon to all remaining coral snakes. The latter group is divided into two large sister-groups. The first is comprised of the sister-groups of Micrurus mipartitus and its relatives (M. multifasciatus, M. multiscutatus, and M. spurrelli) and a large group of species of Micrurus generally possessing a tricolor monadal pattern. The second group is comprised of the sister-groups of Leptomicrurus and the South American members of Micrurus possessing a tricolor triadal pattern.I split Micrurus into three monophyletic genera because the recognition of Leptomicrurus results in Micrurus being paraphyletic. Thc new genus Erythrokomophis is proposed for the Micrurus mipartitus group and the new genus Monadophis is proposed for its sister-group. Micrurus (sensu novo) is retained for the South American triadal species, which include the type of the genus (Micrurus spixii). The other genera, Leptomicrurus and Micruroides are left unmodified.Using the generic relationships, general hypotheses for the evolution of body and head coloration in coral snakes were developed. Under these hypotheses, the tricolored monadal pattern is regarded as the ancestral body pattern for all coral snakes and the 13 other distinct patterns are derived from this pattern. The A pattern, characterized by a black head cap followed posteriorly by a light head element, followed in turn by a black nuchal collar, is the ancestral head pattern.

Keywords

Biology, Molecular; Biology, Zoology

Link to Full Text

http://access.library.miami.edu/login?url=http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:9214836