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Date of Award

4-17-1998

Document Type

Restricted Thesis: Campus only access

Degree Name

Bachelor of Science

Department

Biology

First Advisor

Dr. Rafael O. de Sa

Abstract

The genus Gastrophryne comprises 5 species: G. usta, G. carolinensis, G. olivacea, G. elegans, and G. pictiventris. The combined distribution of these species ranges from Honduras and El Salvador to Iowa, USA. Gastrophryne carolinensis and G. olivacea represent the northernmost range of the genus and are widely distributed in the USA. Relationships among these species have been previously studied by Nelson (1972) who suggested a sister taxa relationship between the two most northern species. Herein, we present a preliminary analysis of relationships based on 12S mitochondrial ribosomal DNA sequences. Both strands of a segment of the 12S mt RNA gene were sequenced. Information was obtained on 429 base pair positions for each taxa, among which 89 positions (about 21 %) were variable. Dyscophus was used as the outgroup and characters were run unordered. Two equally parsimonious trees (36 steps long, C.I.=0.667) were obtained that alternatively placed G. elegans as the sister taxa of G. carolinensis and G. olivacea. Weighting transversions over transitions (10/1), we obtained a single tree (30 steps long, C.I.=0.7) that supports a sister taxa relationship between G. elegans and G. olivacea. This preliminary analysis does not support the closer relationship between the two North American species.

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