OREONETIDES BEATTYI, A NEW TROGLOBITIC SPIDER(ARANEAE: LINYPHIIDAE)FROM EASTERN NORTH AMERICA, ANDRE-DESCRIPTION OF OREONETIDES FLA VUS

摘要

A new troglobitic Linyphiidae, Oreonetides beattyi n.sp., is described fromcaves of eastern North America. The species is morphologically close to Oreonetidesflavus Emerton and proposed as sister-species. Both species are described, illustrated andtheir distribution is documented. The intra-specific variation of O. beattyi is detailed:female genitalia display unusual variability, but males provided stable species leveldiagnosis. A male from Bull Cave (Tennessee) that shows significant genitalic variation isproblematic, however. With limited sampling, the genetic bar-coding approach did notprovide helpful insights to determine if this specimen belongs to a different species, ismorphologically aberrant, or simply belongs to a population geographically distantenough to explain genetic variability. We propose the cryophilic affinities/relictpopulation hypothesis to explain the ecological affinities of some Linyphiidae that arerestricted to caves in most of their ranges, but occur on the surface at the northern edgeof their distribution. We suggest an evolutionary scenario for the disjunct distribution ofOreonetides beattyi n.sp. in eastern caves and O. flavus in more northern latitudes on thewest coast of North America.