AbstractsBiology & Animal Science

Geographical variation and distribution of the Johnny darter (Boleosoma nigrum olmstedi) in Quebec.

by Charles Eric. Hall




Institution: McGill University
Department: Department of Zoology.
Degree: MS.
Year: 1942
Keywords: Osteichthyes.; Fishes  – Québec (Province)  – Geographical distribution.
Record ID: 1523942
Full text PDF: http://digitool.library.mcgill.ca/thesisfile129818.pdf


Abstract

The tessellated darters of the genus Boleosoma were first described by Rafinesque who,in 1820,named the Johnny darter Etheostoma nigrum. The type specimen was from the Green River of Kentucky. The species was transferred to the new genus Boleosoma by De Kay in 1842,and thus became Boleosoma nigrum. This and related genera have been grouped together by some taxonomists into the family Etheostomidae,though they are now usually included with other perch-like fishes in the family Percidae. The Johnny darter belongs to a group of fish which is apparently prone to speciation. A glance at the taxonomic history of the darters will clearly show that,with the passage of time,a greater number of species and subspecies are being recognized. Since the purpose or the writer's work is to demonstrate that in Quebec the Johnny darter 1s represented by three races or populations that are separable on the basis of squamation and the number of rays in the soft dorsal fin, it would perhaps be advisable to describe the species nigrum and a few of its subspecies. [...]