Tinytrema, PLATNICK, 2002

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-

Tinytrema , new genus

TYPE SPECIES: Tinytrema bondi , new species.

ETYMOLOGY: The generic name is an arbitrary combination of letters considered feminine in gender.

DIAGNOSIS: These small, extremely flattened (almost paper­thin) spiders are easily distinguished from all other trochanteriids by having the leg coxae separated by sclerotized extensions of the epimeric sclerite. At least some species are behavioral ant mimics (M. Harvey, pers. commun.); the white spots on the abdomen of some species may enhance the illusion by simulating the appearance of a thorax/abdomen separation.

DESCRIPTION: Small spiders, total length of males 2–3, of females 2–4. Carapace greatly flattened, with numerous tubercles, with rebordered lateral margins and broadly reflexed posterior margin, setae numerous, recumbent; thoracic groove almost obsolete, transverse; cephalic groove almost obsolete. Eight subequal eyes in two rows; anterior medians circular, dark, posterior medians irregularly rectangular, lenses flattened, canoe­shaped tapetum present, laterals oval; from above, both eye rows straight, from front, both rows slightly procurved; anterior medians separat­ ed by more than their diameter, closer to anterior laterals; posterior medians separated by more than their diameter, farther from posterior laterals; anterior and posterior laterals separated by more than their diameters; median ocular quadrangle slightly wider in back than in front or than long. Chelicerae inclined, parallel, with distinct oblique groove just below clypeus; anterior surface with few stiff setae; chilum wide, triangular, unipartite, entire, fused to carapace, accompanied by second, elongated, posterior chilum (narrow, I­shaped sclerite separating bases of chelicerae posteriorly); chelicerae with distinct lateral boss, promargin with few long setae originating in line along base of fang, those nearest base of fang not bent; promargin with four or five small, closely spaced teeth, second most proximal largest; retromargin with two low teeth near base of fang; cheliceral gland openings not obvious under light microscopy. Labium greatly elongated, extending about three­quarters of endite length, flat, triangular, with slight invaginations just beyond posterior margin, anterior margin narrow, not invaginated near midline. Endites long, slightly convergent, with oblique depression shallow, restricted to their median edge; serrula present (fig. 151), sieve plate not conspicuous under light microscopy; anteromedian edges and apex bearing wide patch of long, stiff, dark setae. Sternum flat, shield­shaped, with rebordered, slightly depressed lateral margins, not expanded anteriorly, with triangular extensions to and be­ tween coxae; surface smooth, with few long setae, posterior margin wide, separating coxae IV, not fused to ventral pedicel sclerite. One heavily sclerotized epimeric sclerite on each side, extending between coxae, not fused to carapace or each other. Pedicel composed of two dorsal sclerites (anterior sclerite without deep posterior invagination, posteri­ or sclerite without beak­shaped anterior extension) and strong, ventral sclerite with transverse anterior margin.

Abdomen with shiny, narrow dorsal scutum in male; cuticle with sparse, erect setae; epigastric scutum weakly sclerotized, with well­marked booklung openings at sides, without postepigastric sclerotizations, booklung covers not ridged; spinnerets and colulus tiny, details difficult to document with light microscopy. Anterior lateral spinnerets short, conical, separated by about their diameter at base, apparently with two articles bearing relatively few spigots; posterior median spinnerets of females wider than those of males, apparently with two large cylindrical gland spigots; posterior lateral spinnerets with two articles, those of females apparently with one cylindrical gland spigot.

Legs long, laterigrade, leg formula 1243, with sparse setae and few, weak spines; anterior coxae with dorsal tubercles, fourth trochanters about 1.5 times longer than third; anterior coxae without protuberant posterolateral corners; trochanters not notched; metatarsal and tarsal scopula weak; posterior metatarsi with weak distal preening brushes; tarsi with two relatively short claws bearing few teeth; claw tufts represented only by few scattered setae; tarsi without cuticular cracks, relatively short; morphologically dorsal surface with modified proximal margin consisting of patch of cuticle with narrow, u­shaped sclerotization followed by strong cuticular ridge, that ridge opposing distinct distal extensions situated at distal edge of metatarsi; trichobothria present, apparently in three rows on tarsi, two on metatarsi and tibiae. Female palpal femur with single dorsal bristle, distal segments with few long bristles; female palpal tarsus with small, apparently toothed claw, without ventral scopula. Typical leg spination pattern (counts refer to morphological surfaces, only surfaces bearing spines listed): tibiae III, IV v1p­1p­0.

Male palpal tibia with relatively huge retrolateral apophysis, embolus relatively short. Epigynum with coiled or convoluted ducts.