Diploglena Purcell, 1904

Platnick, Norman I. & Jäger, Peter, 2008, On the First Asian Spiders of the Family Caponiidae (Araneae, Haplogynae), with Notes on the African Genus Diploglena, American Museum Novitates 2008 (3634), pp. 1-12 : 7-10

Diploglena Purcell

Diploglena Purcell, 1904: 169 (type species by monotypy Diploglena capensis Purcell, 1904 ).

DIAGNOSIS: Specimens of this nonnopine genus can easily be recognized by the shape of the palpal endites (fig. 27), which are distally expanded and have a sinuous anterolateral margin. Among the other described caponiids, members of the Mexican genus Nopsides Chamberlin and the Chilean genus Tisentnops have endites that are similarly expanded (see Chamberlin, 1924: fig. 39; and Platnick, 1994: fig. 26). Nopsides is a nopine, and its members can easily be distinguished from those of Diploglena by the subsegmented tarsi, but they also resemble those of Diploglena in having the anterior median eyes set farther back on the carapace than is typical for the family. In Nopsides , though, there are four eyes present, with the presumptive anterior lateral pair occurring midway between the anterior margin of the clypeus and the anterior median eyes ( Chamberlin, 1924: fig. 38), whereas in Diploglena only two eyes occur. Specimens of Tisentnops (which is not a nopine) can easily be distinguished from those of Diploglena by the presence of a row of squared tubercles on the anterior margin of the endites ( Platnick, 1994: fig. 26). Although the two eyes of Tisentnops are differently placed (anteriorly advanced rather than unusually posterior), they are greatly reduced in size ( Platnick, 1994: fig. 4), a character also true for Diploglena (to a slightly lesser degree, fig. 26). It is possible that the reduction in eye size is a synapomorphy uniting Diploglena with Tisentnops . Diploglena specimens are also notable for the enlarged femora, patellae, and tibiae found on the first pair of legs (and, to a lesser degree, the second). The femora are laterally compressed, especially proximally, but all three leg segments are more than twice as high as the metatarsi and tarsi.

DESCRIPTION: Moderate-sized caponiids with two eyes (figs. 26, 27). Carapace oval, pars cephalica flattened, slightly narrowed opposite palpal coxae, pars thoracica slightly sloping; cuticle with raised sculpturing outlining irregularly rectangular cells, with scattered long, weak setae concentrated at rear of pars cephalica and around ocular area; thoracic groove obsolete. Eyes dark, separated by about their diameter, set back from anterior margin of clypeus by about five times their diameter, surrounded by oval ring of black pigment. Chelicerae paturon with clump of strong bristles along anteromedian face, bristles of each side overlapping distally, clump occupying almost total length of paturon; median lamina long, without sclerotized anteromedian tip, about two-thirds of space between lamina and base of fang occupied by white membranous lobe; lateral surface with stridulatory ridges (pick at base of prolateral side of palpal femur, fig. 29). Endites expanded distally to almost twice their width at base, with laterally sinuous distal margin, serrula not apparent, seemingly fused with distal endite margin, median surface of anterior face unsclerotized. Labium almost diamond-shaped, not fused to sternum; anterior surface of labrum with pair of long, longitudinal, submarginal sclerotized strips. Sternum oval but with slightly produced knobs at anterolateral corners, opposite lateral sides of endite bases, cuticle with scattered depressions; cephalothoracic membranes with weak epimeric sclerites dorsally between coxae I and II, II and III, and III and IV; epimeric sclerites not fused with triangular sclerites extending from sternal margin to and between coxae. Female palpal tarsus expanded, extremely hirsute but without well-defined dorsal pad of short setae. Leg formula 4123; legs without spines; metatarsi and tarsi entire, without subsegmentation or membranous processes; tarsi with three claws; paired claws with about six relatively short teeth, unpaired claw short, without teeth, almost fused to protruding onychium. Tarsal organ not scanned; trichobothria present on tibiae, metatarsi, and tarsi, their bases not scanned. Abdomen with two pairs of respiratory spiracles clustered around epigastric groove; internal anatomy not investigated. Spinnerets in typical caponiid arrangement, with posterior medians situated almost as far forward as anterior laterals; spigots not scanned, but females apparently with single, large cylindrical gland spigot situated at center of posterior median spinneret spigot field (no similarly enlarged spigot evident on posterior laterals). Male palpal patella and tibia short, unmodified; cymbium ovoid, with distinct dorsal pad of short setae; embolus accompanied by second tegular apophysis (figs. 28–30). Female epigastric area with pair of transverse sclerotized strips, almost meeting at midline.

DISTRIBUTION: Known only from South Africa and Namibia.