The Spider Family Leptonetidae in North America

Gertsch, Willis

ABSTRACT: A systematic review of spiders of the family Leptonetidae in North America is presented analyses of their characters and relationships. Reasons are given for using only two generic the 44 taxa of this fauna, most of which are described as new. The subfamily Leptonetinae includes representatives of the world fauna in which the posterior median eyes are situated far posterior lateral eyes. The genus Leptoneta, which is the basic standard of the family widely in Palearctica, is considered to include all but three of the American species. distribution in North America makes possible treatment of different faunas of four quite centers of distribution. The largest fauna of 15 species occurs in the southern Appalachian includes six epigean species and nine cavernicoles; of the latter one from Georgia is troglobite and others have eyes in various stages of reduction. A dozen species from the Plateau Region of middle Texas and some outlying districts are related to those of Appalachia; the nine cavernicoles is eyeless and others have rudimentary eyes. Nine species from eastern show more morphological variability but differ little in basic features from those from eastern United States; two of them are blind troglobites. The five Californian representatives Leptoneta are all big-eyed epigean types notable for remarkable, derivative modifications palpi of some. A new genus Archoleptoneta is given subfamily status for various unusual features. posterior median eyes form a transverse row with the posterior lateral eyes in an eye formula reminescent of the ancestral stock of the family. The male palpus presents generalized features bulb and especially of the tarsus which lacks a transverse groove present in various degrees of development in the Leptonetinae. Archoleptoneta is an exclusively American group so far known species in California, Texas and Chiapas, Mexico.