Afroceto flabella, Lyle & Haddad, 2010

Lyle, Robin & Haddad, Charles R., 2010, A revision of the tracheline sac spider genus Cetonana Strand, 1929 in the Afrotropical Region, with descriptions of two new genera (Araneae Corinnidae), African Invertebrates 51 (2), pp. 321-321 : 354-357

Afroceto flabella sp. n.

Figs 13, 14 , 72–76

Etymology: From Latin flabellum (small fan); refers to the flattened, fan-like structure of the male embolus.

Diagnosis: The male can easily be recognised by the flattened tip of the embolus and the U­shaped sperm duct running along the margins of the tegulum, and the small, sharply pointed retrolateral tibial apophysis ( Figs 73, 74 ). The female can easily be recognised by the broad subtriangular shape of the anterior epigynal hood with lateral extensions leading to the copulatory openings ( Fig. 75 ), along with small spherical ST II above the copulatory openings, and large, oval, laterally projecting ST I ( Fig. 76 ).

Description:

Male.

Measurements: CL 2.80, CW 2.28, AL 2.90, AW 1.75, TL 5.50, FL 0.18, SL 1.53, SW 1.30, AME–AME 0.13, AME–ALE 0.05, ALE–ALE 0.53, PME–PME 0.15, PME–PLE 0.18, PLE–PLE 0.80. Length of leg segments (sequence from femur to tarsus, and total): I 2.38+1.10+2.05+1.55+1.03=8.11; II 2.20+1.00+1.78+1.50+1.05=7.33; III 1.48+ 0.75+1.13+1.30+0.60=5.26; IV 2.18+0.85+1.73+2.00+0.68=7.44.

Carapace dark orange, fading to pale yellow posteriorly ( Fig. 13 ); first third of carapace rounded, last two thirds with a gradual decline; surface smooth, covered in short, fine setae; fovea short, distinct, at two thirds abdomen length. Ocular region brown with dark brown rings around eyes; AER very slightly recurved, AME slightly larger than ALE; clypeus height subequal to AME diameter; AME separated by distance approximately equal to 0.8 their diameter; AME separated from ALE by 0.4 AME diameter; PER recurved, PME slightly larger than PLE; PME separated by approximately 1.1 times their diameter; PME separated from PLE by distance equal to PME diameter. Chelicerae brown, darker towards fang base; long, fine setae scattered on anterior surface, slightly longer towards fang base; fangs bright orange, darkening towards fang base; three promarginal teeth, median tooth largest, proximal tooth smallest; two retromarginal teeth, distal tooth largest. Sternum pale yellow, brown towards border; surface covered in short fine setae. Abdomen pale yellow to orange dorsally, with broad yellow stripe laterally and orange band dorsally across abdomen; abdomen broader anteriorly, tapering posteriorly; scutum almost covering entire abdomen length; two pairs of distinct sigilla, anterior pair slightly paler brown than posterior pair, situated either side of midpoint; venter pale yellow­grey. Anterior legs pale brown and more robust, posterior legs darker brown; metatarsi and tarsi covered with dense scopulae, remaining leg segments covered in pale fine setae; leg spines and cusps present. Leg spination: femora: I pl 3, II pl 3; patellae spineless; tibiae: I plv 7 cusps, II plv 4 cusps, III pl 1 plv 2 vt 2, IV plv 4 vt 2; metatarsi: I plv 7 rlv 6 vt 1 cusps, II plv 9 rlv 4 cusps, III pl 1 rl 1 plv 2, IV plv 4 rlv 1; tarsi: I plv 5 rlv 9 cusps, II plv 8 rlv 1 cusps ( Fig. 72 ). Palp yellow­brown, tegulum elongate; embolus originating prolaterally, curving retrolaterally, tip round and flattened; sperm duct U­curved, narrower at embolus base; retrolateral tibial apophysis small, triangular, sharply pointed ( Figs 73, 74 ).

Female.

Measurements: CL 2.70, CW 2.10, AL 3.20, AW 1.80, TL 5.90, FL 0.13, SL 1.60, SW 1.28, AME–AME 0.13, AME–ALE 0.05, ALE–ALE 0.53, PME–PME 0.15, PME–PLE 0.18, PLE–PLE 0.83. Length of leg segments (sequence from femur to tarsus, and total): I 2.28+1.05+1.68+1.40+1.10=7.51; II 2.03+0.95+1.50+1.40+1.03=6.91; III 1.58+ 0.88+1.08+1.30+0.58=5.42; IV 2.30+0.75+1.80+2.10+0.65=7.60.

Carapace light orange, paler orange posterior to midpoint ( Fig. 14 ); first third of carapace rounded, last two thirds with gradual decline; surface covered in short fine setae; fovea short, distinct, thickened, at two thirds CL. Ocular region orange with dark brown rings around eyes; AER recurved, AME slightly larger than ALE; clypeus height equal to AME diameter; AME separated by distance slightly less than their diameter; AME separated from ALE by distance equal to 0.5 AME diameter; PER recurved, PME and PLE subequal in size; PME separated by distance equal to their diameter; PME separated from PLE by distance equal to PME diameter. Chelicerae brown, darker towards fang base; long, fine setae scattered on anterior surface; fangs orange­brown; three promarginal teeth, median tooth largest, distal tooth smallest; two retromarginal teeth, distal tooth largest. Sternum pale yellow, brown towards border; surface with scattered long brown setae. Abdomen cream, without markings dorsally; abdomen broader anteriorly, tapering posteriorly; venter cream. Legs I to IV uniform light brown; anterior legs slightly more robust than posteriors; tibiae, metatarsi and tarsi with dense scopulae ventrally, remaining segments covered with fine setae; cusps absent. Leg spination: femora: I pl 1; patellae spineless; tibiae: III pl 1 plv 2, IV plv 2 vt 2; metatarsi: III pl 1 rl 1 plv 1, IV pl 1 rl 1 plv 2. Epigyne weakly sclerotised; anterior hood subtriangular, with lateral extensions leading to copulatory openings; ST II small, rounded, anterior to copulatory openings; ST I large, oval, projecting laterally, situated posterior to copulatory openings ( Figs 75, 76 ).

Holotype ♂ and Allotype ♀: SOUTH AFRICA: Eastern Cape: Grahamstown [33.3°S: 26.5°E], ii.1933, R.F. Lawrence ( SAMC, B8279 ) .

Distribution: Known only from the type locality ( Fig. 80 ).

Figures

Figs 1–22. General appearance of Afroceto gen. n. species: A. martini (Simon, 1897) comb. n. female (1) and male (2); A. arca sp. n. female (3) and male (4); A. bulla sp. n. female (5); A. bisulca male (6); A. capensis sp. n. female (7) and male (8); A. coenosa (Simon, 1897) comb. n. female (9); A. corcula sp. n. female (10); A. croeseri sp. n. female (11) and male (12); A. flabella sp. n. male (13) and female (14); A. gracilis sp. n. male (15); A. plana sp. n. male (16) and female (17); A. porrecta sp. n. male (18); A. rotunda sp. n. male (19) and female (20); A. spicula sp. n. male (21) and female (22).

Figs 72–76.Afroceto flabella sp. n. male (72–74) and female (75–76):(72) schematic representation of cusp arrangement on legs I and II; (73) left palp, ventral view; (74) left palp, retrolateral view; (75) epigyne, ventral view; (76) vulva, dorsal view. Scale bars (73–76) = 0.1 mm.

Fig. 80. Distribution of Afroceto croeseri sp. n., A. flabella sp. n. and A. gracilis sp. n. in South Africa.