Poachelas striatus, Haddad & Lyle, 2008

Haddad, Charles R. & Lyle, Robin, 2008, Three new genera of tracheline sac spiders from southern Africa (Araneae: Corinnidae), African Invertebrates 49 (2), pp. 37-37 : 67-71

Poachelas striatus sp. n.

Figs 72, 73 , 76–95 , 100

Etymology: From Latin striatus (striate), the name refers to the distinctive median stripe running along the abdomen.

Diagnosis: P. striatus sp. n. can be recognised from the only other species in this group by the genitalic morphology, with an embolus coiled around the tegulum and ending near the cymbial tip.

Description:

Male.

Measurements: CL 1.30–1.47, CW 0.83–0.98, AL 1.46–1.80, AW 0.75–0.87, TL 2.63– 3.25, FL 0.08–0.09, SL 0.87–0.95, SW 0.53–0.61, AME–AME 0.03, AME–ALE 0.015, ALE–ALE 0.19, PME–PME 0.09, PME–PLE 0.07, PLE–PLE 0.37. Length of leg segments: I 1.18+0.57+1.07+0.83+0.48=4.13; II 0.87+0.47+0.68+0.59+0.40=3.01; III 0.60+0.33+0.43+0.47+0.27=2.10; IV 1.13+0.50+1.10+0.92+0.40=4.05.

Carapace bright yellow, paler posteriorly, with pale grey stripe from between PME to midpoint, forming small rectangular grey marking medially ( Fig. 72 ); carapace flattened with highest point at 1/3 carapace length, sloping gently to posterior, last fifth declining more steeply ( Fig. 88 ); surface smooth with scattered short fine setae; fovea indistinct, lying in shallow median depression, at 2/3 carapace length. Eyes surrounded by black rings; AER procurved, lateral eyes larger than medians; clypeus height equal to approx. 0.66× AME diameter; AME separated by approx. 1/3 their diameter; AME separated from ALE by approx. 1/8× AME diameter ( Fig. 89 ); PER recurved, median eyes slightly larger than laterals; PME separated by distance slightly larger than their diameter; PME separated from PLE by distance slightly smaller than PME diameter. Chelicerae pale yellow; anterior surface slightly granulate, with scattered short and long fine setae; promargin with three small teeth, distal tooth largest, proximal and median teeth subequal; retromargin with two closely spaced teeth, distal tooth slightly larger. Sternum cream with faint grey mottling, slightly darker along border; surface smooth, with scattered short fine setae. Abdomen: cream with pale grey mottling, with broad grey median stripe dorsally running along abdomen, expanding laterally above spinnerets ( Fig. 72 ); elongate, twice as long as wide, broadest at half its length; dorsal scutum absent; surface covered in short fine setae; two pairs of indistinct oval sigilla present, first at 1/4 abdomen length, second pair anterior to midpoint; venter without sclerites. Legs I to IV with pale yellow femora; patellae, tibiae and tarsi I dark yellow-brown, metatarsi I dark brown; legs II to IV pale yellow-brown; legs covered in short fine setae with scattered long erect setae, particularly on femora, patellae and tibiae; metatarsi III and IV with terminal preening comb; tarsi I and IV with rows of short erect plv and rlv setae; leg spination: femora: I pl 2; patellae: I plv 2; tibiae: I plv 5–7 rlv 6 spines, plv 1–2 cusps, II rlv 0–2 spines; metatarsi: I plv 3–5 rlv 3–4 spines, plv 4–10 rlv 0–2 cusps, II rlv 4 spines, plv 1– 4 cusps; tarsi: I plv 1–2 cusps. Male palp with fine curved retrolateral tibial apophysis ( Figs 85, 86 , 90, 91 ); tegulum round, embolus fine, originating distally, curving around tegular margins before looping retrolaterally, curving along distal retrolateral margin to tip of cymbium ( Figs 90, 91 ).

Female.

Measurements: CL 1.26–1.43, CW 0.91–1.00, AL 2.00–2.28, AW 1.07–1.20, TL 3.10– 3.58, FL 0.13–0.17, SL 0.87–0.94, SW 0.57–0.61, AME–AME 0.03, AME–ALE 0.01, ALE–ALE 0.17, PME–PME 0.07, PME–PLE 0.08, PLE–PLE 0.36. Length of leg segments: I 1.07+0.61+0.98+0.82+0.45=3.93; II 0.87+0.45+0.76+0.57+0.43=3.08; III 0.67+0.37+0.43+0.45+0.28=2.20; IV 1.20+0.57+1.20+1.00+0.43=4.40.

Carapace pale yellow, sometimes with pale grey mottling, with pale grey stripe from PER to midpoint, forming rectangular grey marking medially ( Fig. 73 ); eye region at AER black; carapace flattened with highest point at 1/3 carapace length, sloping gently to posterior, last fifth declining more steeply ( Fig. 92 ); surface smooth with dense short fine setae; fovea indistinct, lying in shallow median depression, at 2/3 carapace length. Eyes surrounded by black rings;AER procurved, lateral eyes larger than medians; clypeus height slightly larger than 0.5× AME diameter; AME separated by 0.33× their diameter; AME separated from ALE by approx. 1/8× AME diameter ( Fig. 93 ); PER slightly recurved, eyes subequal; PME separated by distance slightly less than their diameter; PME separated from PLE by distance equal to PME diameter. Chelicerae pale yellow; anterior surface smooth, with scattered short and long fine setae; promargin with three small teeth, median and distal teeth largest, subequal in size; retromargin with two closely situated teeth, distal tooth largest. Sternum cream, dark yellow along border; surface smooth, covered in long fine setae. Abdomen: cream, with broad grey median stripe dorsally running along abdomen, expanding laterally in posterior third ( Fig. 73 ); elongate, twice as long as wide, broadest at half its length; dorsal scutum absent; surface covered in short and long fine setae; two pairs of indistinct oval sigilla present, first pair at 1/4 abdomen length, second pair at anterior to midpoint of abdomen; venter without sclerites. Legs I to IV with pale yellow femora; patellae, tibiae, metatarsi and tarsi I and I dark yellow-brown, legs II to IV pale yellow-brown; legs covered in short fine setae with scattered long erect setae, particularly on femora and patellae; metatarsi III and IV with terminal preening comb; tarsi I and IV with rows of short erect plv and rlv setae; leg spination: femora: I pl 3–5 rlv 7; patellae: I plv 2–4 rlv 1; tibiae: I plv 6–7 rlv 6–8, II rlv 4–5; metatarsi: I plv 4–7 rlv 4–5, II rlv 5–7; palp spineless, with several long fine erect setae on femora and patellae. Epigyne with copulatory openings situated anterolaterally in posterior lip-shaped ridge ( Figs 87 , 94 ); entrance ducts coiling before entering large round anteromedian ST I, with broad median ducts leading from ST I to posterolateral oval ST II ( Fig. 95 ).

Holotype: ♂ SOUTH AFRICA: “R.S.A., Free State Province / Bloemfontein District / Glen Agricultural College / 28°54'S, 26°21'E / 16.iv.2008, J. van Niekerk / Base of grass tussocks // Holotype ♂ / Poachelas striatus / NMBA 11582 //” ( NMBA, 11582 ).

Allotype: ♀“ NMBA 10907 / South Africa, FS / Bloemfontein , Botanical Gardens / 2908S/2610E, / L. Lotz, Oct 2006 / pit-trap 2, in grassland near office // Allotype ♀/ Poachelas striatus / NMBA 10907 //” (NMBA, 10907).

Paratypes: SOUTH AFRICA: Free State: 3♀Bloemfontein, National Botanical Gardens , 29°02'44''S: 26°12'34''E, 13.xi.2007, C. Haddad, base of grass tussocks ( NCA, 2007/3804 ) ; 1 imm. 1 ♂ same locality, 24.iv.2008, C. Haddad, base of grass tussocks ( NCA, 2008/582 ) ; 2 imm. 5 ♂ 14♀same locality, 28.v.2008, C. Haddad, base of grass tussocks ( NCA, 2008/589 ); 1 ♂ 8♀Erfenis Dam Nat. Res., Weedy grassland , 28°29.722'S: 26°48.439'E, 28.viii.2007, C. Haddad, searching, base of grass tussocks ( NCA, 2007/3142 ) ; 1 imm. 1 ♂ Glen Agricultural College , 28°54'S: 26°21'E, 24.iv.2008, J. van Niekerk, base of grass tussocks ( NMBA, 11583 ) .

Biology: This species was commonly found at the base of grass tussocks, and occasionally caught by sweep-netting. The adults from the National Botanical Gardens were collected during spring. By late summer (March 2008) no adults were collected, although more than 25 immature specimens were observed. In the following month males started to appear. By the end of May nearly no immatures were collected, only adults. This suggests a life cycle where adults breed in spring and early summer, immatures develop through summer, maturing in early autumn, with the adults overwintering and breeding the following spring. One adult female maintained in the laboratory produced an egg sac of 6.0 mm diameter, consistent in structure with other corinnids (foundation disc of silk on which eggs are laid, covered by a disc of papery silk). Eight cream-coloured oval eggs were produced, each being approx. 0.60× 0.68 mm.

Distribution: Known only from the Grassland Biome in Free State ( Fig. 100 ).

Figures

Figs 72–75. General habitus of Poachelas gen. n. species: (72, 73) P. striatus sp. n., male, Erfenis Dam Nat. Res., and female, Bloemfontein; (74) P. solitarius sp. n., male, Maleme Rest Camp; (75) P. montanus sp. n., female, Platberg Nat. Res. Scale bars = 1.0 mm.

Figs 76–87. Scanning electron micrographs of Poachelas striatus sp. n.: (76) female, serrula; (77) female, patella, prolateral view; (78) male, leg I, indicating ventral spines (SP) and cusps (CU); (79) male, cusps on metatarsus I; (80) male, metatarsal cusp enlarged; (81) female, tibia I with plv spines missing and rlv spines present; (82) female, tibial spine base; (83) male, tarsal claw and claw tufts; (84) male, metatarsus IV preening comb; (85) male palp, ventral view; (86) male palpal RTA; (87) female, epigyne, ventral view.

Figs 88–95. Poachelas striatus sp. n., male (88–91) and female (92–95): (88, 92) carapace, lateral view; (89, 93) eye region, anterior view; (90, 91) palp, ventral and retrolateral views; (94, 95) female epigyne, ventral and dorsal view. Scale bars: 1.0 mm in Figs 88, 92; 0.1 mm in Figs 89–91, 93–95.

Fig. 100. Distribution of Poachelas gen. n. species.