Trachytrema Simon

PLATNICK, NORMAN I., 2002, A Revision Of The Australasian Ground Spiders Of The Families Ammoxenidae, Cithaeronidae, Gallieniellidae, And Trochanteriidae (Araneae: Gnaphosoidea), Bulletin of the American Museum of Natural History 2002 (271), pp. 1-1 : 1-

Trachytrema Simon

and retain some (albeit short and weak) leg spines.

DESCRIPTION: Medium­sized spiders, total length of males 5–6, of females 6–7. Carapace flattened, without tubercles, with rebordered lateral and posterior margins, setae long, dark, confined to ocular area and clypeus; thoracic groove long, Y­shaped, wider anteriorly than posteriorly; cephalic groove scarcely detectable. Eight subequal eyes in two rows; anterior medians circular, light, posterior medians irregularly rectangular, lenses flattened, canoe­shaped tapetum apparently present, laterals oval; from above, anterior eye row procurved, posterior row recurved, from front, both rows procurved; anterior medians separated by more than their diameter, farther from anterior laterals; posterior medians separated by about four times their diameter, farther from posterior laterals; anterior and posterior laterals separated by more than twice their diameters; median ocular quadrangle much wider in back than in front or than long. Chelicerae porrect, divergent, with distinct oblique groove just below clypeus; anterior surface with few stiff setae; chilum wide, triangular, unipartite, entire, accompanied by second, elongated, posterior chilum (narrow, T­shaped sclerite separating bases of chelicerae posteriorly); chelicerae with distinct lateral boss, promargin with se­ Trachytrema Simon, 1909: 157 (type species by original designation Trachytrema castaneum Simon ).

DIAGNOSIS: As first hypothesized by Simon (1909), this appears to be a relative of Trachycosmus , sharing with it a greatly elongat­ ed embolus. Males have a paracymbium (a distinct hook at the basal retrolateral edge of the cymbium, fig. 312) that is absent in Trachycosmus , and lack the distally elongated cymbial tip synapomorphic for that genus; females have smaller, less squared epigyna ries of long setae originating in line along base of fang, those nearest base of fang bent; promargin with four subequally spaced and sized teeth, retromargin with two widely separated teeth; presumptive cheliceral gland openings proximal to base of proximal tooth. Labium broadly triangular, flat, abruptly narrowed at about one­fourth of length, anterior margin slightly invaginated near midline. Endites long, divergent, with oblique depression restricted to their median edge; serrula present ( T. garnet , fig. 288) or absent ( T. castaneum , fig. 154), sieve plate not conspicuous under light microscopy; anteromedian edges and apex bearing wide patch of long, stiff, dark setae. Sternum flat, with reborder­ ed, slightly depressed lateral margins, not expanded anteriorly, with slight extensions to coxae, detached triangular sclerites between coxae; surface smooth, with few long setae, posterior margin not rebordered, separating coxae IV. One weakly sclerotized epimeric sclerite on each side, not extending between coxae, not fused to carapace. Pedicel composed of two dorsal sclerites (anterior sclerite without deep posterior invagination, posteri­ or sclerite without beak­shaped anterior extension) and strong, inverted y­shaped ventral sclerite with anteriorly unexpanded head not reaching posterior tip of sternum.

Abdomen without dorsal or anterior scutum; cuticle with sparse, erect setae; epigastric scutum weakly sclerotized, with wellmarked booklung openings at sides but without postepigastric sclerites, booklung covers not ridged; colulus represented only by scattered setae clustered near tip of projecting area of sclerotized cuticle situated posterior of wide posterior spiracle; males apparently with scattered short epiandrous spigots. Six spinnerets (figs. 305–310), anterior laterals short, conical, with posterior surface flattened, separated by about their diameter at base, with two articles, distal article apparently with two major ampullate gland spigots and many small, unmodified piriform gland spigots; posterior medians apparently with several aciniform gland spigots and one larg­ er minor ampullate gland spigot, those of males triangular, those of females bipartite, enlarged posterior portion with 5–7 enlarged cylindrical gland spigots in two parallel rows (inner row of 2–4, outer row of three); posterior laterals with two articles, apparently without minor ampullate gland spigots, those of males seemingly with aciniform gland spigots only, those of females with two large cylindrical gland spigots in addition.

Legs slightly laterigrade, leg formula 4123, with few setae and even fewer, weak spines; coxae and trochanters without dorsal tubercles, fourth trochanters slightly enlarged, elongated; anterior coxae without protuberant posterolateral corners; trochanters very slightly notched; metatarsal and tarsal scopula very weak; posterior metatarsi without distal preening brushes; tarsi with two long claws bearing single denticle or smooth; strong claw tufts composed of two large pads of narrow setae; tarsi without cuticular cracks, relatively short; morphologically dorsal surface with modified proximal margin consisting of patch of unsclerotized cuticle followed by strong cuticular ridge, that ridge opposing distinct distal extensions situated at distal edge of metatarsi; trichobothria present, in three rows on tarsi, two on metatarsi and tibiae. Female palpal femur without dorsal spines, distal segments with weak but long spines; female palpal tarsus with long claw, smooth or with few denticles, without ventral scopula. Typical leg spination pattern (counts refer to morphological surfaces, only surfaces bearing spines listed): femur IV d1­0­0; tibiae: III v1p­1p­1p; IV v1p­2­2; metatarsi: I–III v1p­0­0; IV p0­0­ 1p, v2­0­0.

Male palpal tibia with retrolateral apophysis; retrolateral basal corner of cymbium produced into distinct hook (paracymbium); embolus originating on dorsal surface of bulb, only tip of embolus and conductor protruding onto ventral surface of bulb, median apophysis rounded, terminal apophysis elongated. Epigynum with central, excavated atrium.