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Crotalus Scutulatus Salvini
''Crotalus scutulatus salvini'', commonly known as the Huamantlan rattlesnake, is a venomous pit viper, currently classified as a subspecies of ''Crotalus scutulatus, C. scutulatus'' that is found in mainland Mexico, at the southern end of the distribution of ''C. scutulatus''. The subspecific epithet honors the nineteenth century British naturalist Osbert Salvin. Description The original description includes, "On the basis of present knowledge this subspecies differs from ''C. s. scutulatus'' in having less subdivision of the scales of the crown, a lower number of ventrals, and a less vivid coloration." Compared to ''C. s. scutulatus'', ''C. s. salvini'' is distinguished by higher contrast markings with darker dorsal rhombs on very pale background color, with colors of the pale and dark caudal rings matching the body hues. Most specimens lack pale borders surrounding the dorsal rhombs. Many animals lack significant color, but some have a reddish hue to the face and, less freque ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pit Viper
The Crotalinae, commonly known as pit vipers,Mehrtens JM (1987). ''Living Snakes of the World in Color''. New York: Sterling Publishers. 480 pp. . crotaline snakes (from grc, κρόταλον ''krotalon'' castanet), or pit adders, are a subfamily of vipers found in Eurasia and the Americas. Like all other vipers, they are venomous. They are distinguished by the presence of a heat-sensing pit organ located between the eye and the nostril on both sides of the head. Currently, 23 genera and 155 species are recognized: These are also the only viperids found in the Americas. The groups of snakes represented here include rattlesnakes, lanceheads, and Asian pit vipers. The type genus for this subfamily is ''Crotalus'', of which the type species is the timber rattlesnake, ''C. horridus''. These snakes range in size from the diminutive hump-nosed viper, ''Hypnale hypnale'', that grows to a typical total length (including tail) of only , to the bushmaster, ''Lachesis muta'', a specie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Secondary Contact
Secondary contact is the process in which two allopatricaly distributed populations of a species are geographically reunited. This contact allows for the potential for the exchange of genes, dependent on how reproductively isolated the two populations have become. There are several primary outcomes of secondary contact: extinction of one species, fusion of the two populations back into one, reinforcement, the formation of a hybrid zone, and the formation of a new species through hybrid speciation. Extinction One of the two populations may go extinct due to competitive exclusion after secondary contact. This tends to happen when the two populations have strong reproductive isolation and significant overlap in their niche. A possible way to prevent extinction is if there is an advantage to being rare. For example, sexual imprinting and male-male competition may prevent extinction. The population that goes extinct may leave behind some of its genes in the surviving population ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
