A new species of the spider genus Eridantes Crosby & Bishop from the southwestern United States and mainland Mexico with a revised diagnosis of the genus (Araneae, Linyphiidae, Erigoninae)

Abstract

A new Eridantes Crosby & Bishop (1933) species, E. diodontos n. sp., discovered in the United States in the state of Arizona and in Mexico in the state and city of San Luis Potosí, is described and illustrated. Both males and females are very similar to the respective sexes of the type species, E. erigonoides (Emerton 1882), but can be distinguished by the higher cephalic lobe, position of the prosomal pit, and the form of the palpal tibia in the male and by the convolution of the m-shaped carinae of the epigynum in the female. Comparative illustrations of the male bulb of E. erigonoides and a distribution map of the three known species are also provided. Pending formal taxonomic revision of Eridantes, a revised diagnosis and a brief description of the genus are presented based on examination of specimens of the type species and of the new species described here. The mesal rather than ectal position of the paracymbium and the broadly divided dorsal and ventral sclerites of the largely membranous radix are proposed synapomorphies that distinguish Eridantes from all similar genera.