Spinotrachelas capensis, Haddad, 2006

Haddad, Charles R., 2006, Spinotrachelas, a new genus of tracheline sac spiders from South Africa (Araneae: Corinnidae), African Invertebrates 47, pp. 85-93 : 87-91

Spinotrachelas capensis sp. n.

Figs 1–18

Etymology: The species is named for Western Cape Province, where it is endemic. Diagnosis: See genus diagnosis.

Description:

Male.

Measurements: CL 1.70–1.97, CW 1.35–1.55, FL 0.12–0.15, AL 1.85–1.97, AW 1.21– 1.40, TL 3.28–3.80, SL 0.87–0.92, SW 0.72–0.75. Interdistances between eyes: AME– AME 0.07, AME–ALE 0.02, ALE–ALE 0.27, PME–PME 0.13, PME–PLE 0.19, PLE– PLE 0.57.

Length of leg segments (sequence from femur to tarsus, and total): I 1.24+0.62+1.13+ 0.71+0.59=4.29; II 1.12+0.56+0.91+0.70+0.55=3.84; III 0.76+0.45+0.53+0.60+ 0.35=2.69; IV 0.78+0.49+0.75+0.80+0.33=3.15.

General appearance as in Fig. 1 . Carapace convex, low in eye region, highest at half its length, slanting downwards sharply in its posterior third; surface finely wrinkled, with small protuberances at setal bases ( Fig. 8 ); covered in scattered short, straight white setae; shallow transverse depression anterior to fovea ( Fig. 8 ), just posterior to half carapace length; fovea long and fine; carapace uniform dark brown with black mottling; black striae radiating from fovea; ocular region dark brown. All eyes with black rings, except on retrolateral margin; AER strongly procurved, laterals slightly larger than medians; clypeus height equal to ALE diameter; AME separated by their diameter; AME separated from ALE by half AME diameter; PER strongly recurved, medians slightly larger than laterals; PME separated by slightly more than their diameter; PME separated from PLE by two times PLE diameter ( Fig. 1 ). Chelicerae red-brown, with short black setae on anterior surface; three evenly spaced teeth on promargin, median tooth largest, distal tooth smallest; two teeth on retromargin, close together and subequal in size; small cheliceral keel present ( Fig. 9 ); endites orange, rounded on anterior margin with well developed serrula ( Figs 9, 10 ), straight on retrolateral and posterior margins; prolateral longitudinal ridge extending length of endites; labium brown, slightly wider than long. Abdomen oval-elongate, with dorsal scutum covering entire dorsum; dorsum very dark brown, nearly black, with lateral white or cream markings at half abdomen length; dorsum covered with short, straight white setae; epigastric area sclerotised, inframamillary sclerite absent. Spinnerets small, in compact group ( Fig. 11 ); ALS largest, with one distinctive anterior ampullate gland spigot and several small, stout piriform gland spigots; PMS smallest, with three large cylindrical gland spigots and several small piriform gland spigots; PLS with three large cylindrical gland spigots and several small aciniform gland spigots. Legs I and II strongly built and long, legs III and IV weakly built and shorter; tarsal claws small ( Fig. 12 ); coxae I dark brown, II–IV yellow; trochanters dark brown; femora I dark brown, II dark brown, yellow in proximal third, III and IV yellow proximally and dark brown distally; patellae dark brown; tibiae I and II dark brown with large median yellow band, III and IV dark brown with narrow proximal and broad median yellow band; metatarsi and tarsi I and II uniform orange brown, III and IV brown, slightly paler medially; leg spination: femora: I pl 1; patellae: I pl 1; tibiae: I do 1 pl 1 plv 3 rlv 3–4, II do 1 rlv 3, III do 1, IV do 1; metatarsi: I 4–5 plv cusps, 4 rlv cusps, II 4–7 plv cusps, 1 rlv cusp; tarsi: I 7 plv cusps, 7–8 rlv cusps, II 4–5 plv cusps, 3–4 rlv cusps. Palpal patellae with small retrolateral apophysis; palpal tibiae with long, curved sword-like dorsolateral apophysis; single long seta dorsally on apophysis; cymbium with pair of short stout black setae distally ( Fig. 13 ); tegulum elongate-oval, with looping internal ducts; embolus long, wirelike, originating prolaterally, medially on tegulum; partly hidden beneath tegulum, emerging for short distance distally ( Figs 14–16 ).

Female.

Measurements: CL 1.60, CW 1.28, FL 0.10, AL 2.37, AW 1.61, TL 3.95, SL 0.87, SW 0.62, AME–AME 0.05, AME–ALE 0.02, ALE–ALE 0.22, PME–PME 0.10, PME– PLE 0.14, PLE–PLE 0.48.

Length of leg segments (sequence from femur to tarsus, and total): I 0.99+ 0.47+0.79+0.60+0.52=3.37; II 0.93+0.44+0.73+0.54+0.43=3.07; III 0.67+0.39+0.47+ 0.53+0.28=2.34; IV 0.81+0.45+0.72+0.69+0.38=3.05.

General appearance, colouration and cheliceral dentition as for male; female abdomen larger and more oval than that of male; dorsal scutum and inframamillary sclerites absent; legs as for male, but less robustly built; leg spination: femora: I pl 1; patellae: pl 1; tibiae: I do 1 pl 1 plv 3 rlv 3, II do 1 plv 3, III do 1, IV do 1; metatarsi: without any spines or cusps; tarsi: I 2–3 distal plv cusps. Copulatory openings anterolaterally in epigyne ( Fig. 17 ); entrance ducts curving posteromedially before entering spermathecae ( Fig. 18 ); spermathecae narrow and elongate, with small, globose posteromedially situated terminal receptacles.

Holotype: ơ ‘R.S.A., Western Cape Province / De Hoop Nature Reserve, Potberg / 34 ° 22.549'S, 20 ° 32.004'E / 24.iii.2005, C. Haddad / under Eucalyptus bark // Corinnidae / Trachelinae / Spinotrachelas capensis / HOLOTYPE’ (NCA 2005/2011).

Paratypes:6ơ 1^ ‘R.S.A., Western Cape Province / De Hoop Nature Reserve / Bitou number 2 / 34 ° 27.194'S, 20 ° 24.250'E / 16.vii.2005, C. Haddad & R. Lyle / milkwood leaf litter, with ants // Corinnidae / Trachelinae / Spinotrachelas capensis / PARATYPES’ (SAMC 005361).

Other material examined: SOUTH AFRICA: Western Cape Province: 1^ 1 subadult, Clanwilliam, Lambert’s Bay, 32 ° 06'S: 18 ° 18'E, 21.x.1987, E. Visagie, on ground under plants ( NMBA 02008 ); 1ơ De Hoop Nature Reserve , De Hoop Vlei, i.1992, N. Larsen ( SAMC 002425 ) .

Distribution: Endemic to Western Cape Province, South Africa ( Fig. 19 ).

Natural history: This species was collected primarily from leaf litter in fynbos habitats. During July 2005, the adult paratypes and more than 10 immatures were collected from milkwood leaf litter. These specimens were found in association with cocktail ants of the genus Crematogaster Lund, 1831 ( Hymenoptera : Formicidae ), which they apparently mimic. Modifications include pale bands on the legs, a pair of white or cream markings on the abdomen, and the shiny dorsal scutum in males. No behavioural modifications were observed to suggest mimicry, and therefore, mimicry is suspected to be entirely morphological in origin.

Figures

Fig. 1. General habitus of male Spinotrachelas capensis sp. n. Scale bar = 1 mm.

Figs 2–13. Spinotrachelas capensis sp. n., male: (2) leg I, indicating the presence of tibial spines (TS), and cusps (CU) on metatarsi; (3) leg I, indicating prolateral femoral spine (FS), prolateral patellar spine (PS) and paired tibial spines (TS); (4) metatarsus I, cusp arrangement, ventral view; (5) proximal cusp, enlarged; (6) metatarsus II, lateral view; (7) proximal cusp, enlarged; (8) dorsal view of carapace, showing carapace depression (CD); (9) mouthparts, showing cheliceral keel (CK) and serrula (SER) on endites; (10) serrula, enlarged; (11) spinnerets; (12) distal end of tarsus II, indicating tarsal claws (TC); (13) dorsal view of cymbium, indicating modified distal pair of setae.

Figs 14–18. Spinotrachelas capensis sp. n., genitalia: (14–16) male, left palp: (14) prolateral view, (15) ventral view, (16) retrolateral view; (17–18) female: (17) epigyne, ventral view, (18) vulva, dorsal view. Scale bar = 0.1 mm.

Fig. 19. Distribution of Spinotrachelas capensis sp. n.