Distribution of Etheostoma nigrum Rafinesque, Etheostoma olmstedi Storer, and their introgressive hybrid populations in the James River drainage
Date of Award
Master of Science
An analysis of proportional measurements and meristic characters of Etheostoma nigrum and E. olmstedi identified five populations within the James River drainage. Etheostoma nigrum inhabited the montane and piedmont areas through the Fall Line; E. o. atromaculatum was distributed throughout the tidal river and its lower tributaries; and E. o. olmstedi was restricted to creeks on the upper coastal plain. Appomattox River and Falling Creek contained introgressive hybrid populations with character frequency distributions intermediate to those of E. nigrum and E. o. olmstedi. It is proposed that E. nigrum probably entered these drainages through stream piracy on piedmont tributaries of the James and interbred with an established population of E. o. olmstedi.
Clark, John Edward, "Distribution of Etheostoma nigrum Rafinesque, Etheostoma olmstedi Storer, and their introgressive hybrid populations in the James River drainage" (1978). Master's Theses. 421.