The systematics, ecology and zoogeography of the headwater catfish Ictalurus lupus (Pisces)

Typescript (photocopy).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

The systematics, ecology and zoogeography of the headwater catfish Ictalurus lupus (Pisces)

Typescript (photocopy).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

Local Exercise Does Not Prevent the Aortic Stiffening Response to Acute Prolonged Sitting: A Randomized Crossover Trial

Prolonged sitting has been shown to promote endothelial dysfunction in the lower legs. Furthermore, it has been reported that simple sitting-interruption strategies, including calf raises, prevent leg endothelial dysfunction. However, it is unclear whether prolonged sitting affects central cardiovascular health, or whether simple sitting-interruption strategies prevent impaired central cardiovascular health. This study sought to answer two questions: in young, healthy adults 1) does prolonged sitting (3 h) lead to increased aortic stiffness, and 2) do intermittent calf raise exercises to prevent pooling prevent aortic stiffening. Twenty young, healthy participants (21.7 ± 2.5 yr, 70% female, 25.5 ± 6.1 kg/m2) were randomized to 3 h of sitting with (CALF) or without (CON) 10 calf raises every 10 min. Aortic stiffening [carotid-femoral pulse wave velocity (PWV)] was measured in the supine position pre- and post-sitting. Venous pooling during sitting was estimated with total hemoglobin (tHB) concentration using near-infrared spectroscopy. There were no condition × time interactions. Following 3 h of sitting, PWV significantly increased (0.30 ± 0.46 m/s, P \u3c 0.001). There was no condition effect for PWV (P = 0.694), indicating the intermittent calf rises did not preserve central cardiovascular health. tHb was not significantly affected by sitting (P = 0.446) but was 1.9 μM higher for CON versus CALF (P = 0.106). Sitting increases aortic stiffness in young, healthy individuals, a process that may be influenced by lower extremity blood pooling. Calf raises, which have been reported to preserve vascular function in the legs, do not appear to provide sufficient stimulus for maintaining central cardiovascular health