A TROGLOMORPHIC SCULPIN (PISCES: COTTIDAE)
POPULATION: GEOGRAPHY, MORPHOLOGY
AND CONSERVATION STATUS
In high latitudes, troglomorphic fish are absent despite the presence of caves. Glaciations during the Pleistocene may have prevented fish from colonizing this environment until very recent times. Here we present data on the northernmost cave adapted fish in the world, a troglomorphic sculpin (Cottus: Cottidae: Teleostei) from central Pennsylvania. The characters normally used in recognizing troglomorphic fish, blindness and depigmentation, are not fully developed in this population. Nonetheless, these fish have a suite of modifications that readily identify them as cave-adapted: Elongated pectoral fins, more numerous and enlarged cephalic lateralis pores, a broader head, increased subdermal fat reserves, and in the brain, size reduction of the tectum opticum. Individuals from this newly discovered troglomorphic population have been found only in a single cave at the lower end of the Nippenose Valley. Because of the significance and uniqueness of this population, we recommend that the U.S. Fish and Wildlife Service consider this troglomorphic sculpin for listing under the U.S. Endangered Species Act.
Luis Espinasa and William R. Jeffery - A troglomorphic sculpin (Pisces: Cottidae) population: Geography, morphology and conservation status. Journal of Cave and Karst Studies 65(2): 93-100.