Biology ETDs

Publication Date

7-6-1977

Abstract

The possibility that Crotalus atrox and C. scutulatus might hybridize in southeastern Arizona-southwestern New Mexico or in the Big Bend region of Texas was analyzed morphometrically and electrophoretically. Interbreeding of captive Crotalus, and intraspecific variation and interspecific overlap in key morphological characters has led to the incorrect assumption that these species hybridize. Even though they are syntopic primarily in an unstable desert-grassland ecotone where habitat differences are not evident, C. atrox and C. scutulatus are morphologically and biochemically distinct. The apparent lack of geographic, mechanical, and ecological premating isolating mechanisms in syntopic populations off C. atrox and C. scutulatus suggests that gene flow is being prevented between these closely related species by temporal or behavioral mechanisms. There is no significant difference between these species in testicular activity during the summer months of peak activity. This indicates that, of the various premating mechanisms, temporal reproductive isolation does not occur, thus probably leaving only behavioral differences to prevent interspecific mating, thus maintaining species integrity between C. atrox and C. scutulatus.

Language

English

Document Type

Dissertation

Degree Name

Biology

Level of Degree

Doctoral

Department Name

UNM Biology Department

First Committee Member (Chair)

William George Degenhardt

Second Committee Member

Joe Scott Altenbach

Third Committee Member

Roger Conant

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