http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
systematics, ecology and zoogeography of the headwater catfish Ictalurus lupus (Pisces)
The systematics, ecology, life history, zoogeography and distribution of I. lupus were studied in relation to those of its close relative I. punctatus. I. lupus was found to be biochemically, morphologically and ecologically distinct from I. punctatus, but similar in several life history aspects. Evidence from biochemical and morphometric analyses supports an independent specific status for I. lupus. I. lupus was found to be more robust, having a deeper caudal peduncle, broader snout and wider head than I. punctatus. Two osteological characters and a method using four external characters are described that are useful in distinguishing these two species. Habitats of I. lupus were distinguishable from those of I. punctatus based on a multivariate analysis of environmental characters. I. lupus occupied habitats with clearer water and greater amounts of bedrock and cover than I. punctatus. Ages determined from pectoral spine sections were in poor concordance with length frequencies of I. lupus, indicating that this method was not adequate to determine ages. The characteristic instability of their small stream environments was believed responsible. Ictalurus lupus probably evolved in the area of the lower Rio Grande, San Fernando and Soto la Marina after becoming separated from an I. punctatus-like ancestor sometime during the middle Miocene to late Pleistocene. The distribution of I. lupus was found to include headwater and upstream areas of the Rio Grande, Pecos, San Fernando and Soto la Marina Rivers and the Cuatro Cienegas Basin. Museum collections of I. lupus from the Colorado, Guadalupe, San Antonio, and Nueces Rivers were analyzed and appear to have been properly referred to I. lupus; these collections indicate that I. lupus recently occupied a much greater range. Habitat alterations such as dams, agricultural practices and the stocking of I. punctatus are most probably responsible for this range restriction.
"Major subject: Wildlife and Fisheries Sciences."
Includes bibliographical references (leaves 79-82).