Dolichognatha incanescens (Simon)

Smith, Helen M., 2008, Synonymy of Homalopoltys (Araneae: Araneidae) with the genus Dolichognatha (Araneae: Tetragnathidae) and descriptions of two new species, Zootaxa 1775, pp. 1-24 : 15-18

Dolichognatha incanescens (Simon)

Figs 1–16 , 38–53

Homalopoltys incanescens Simon, 1895: 893 . Holotype Ψ, Sri Lanka, Galle. In MNHNP, No.16311, examined. NEW COMBINATION.

Other material examined. SRI LANKA: ɗ, RMNH.ARA.11302 (ex coll. CLD), Ratnapura, 21–22.viii.1981, forest & lake below tennis club. AUSTRALIA: Queensland: 2 Ψ, QM S73921, Bellenden Ker Range, Cableway base stn, 17–24.x.1981, Earthwatch/Qld Museum, 100 m; 2 ɗ 1 Ψ, QM S74359 , Gordon Creek, Iron Range, 24–30.vi.1976, R. Raven, V.E. Davies; 1 ɗ 1 Ψ, AM KS 100890, data as S74359 ; ɗ, QM S74358 , Spear Creek, 3–10.xi.1975, R. Raven, V.E. Davies; 2ɗ, QM S74356 –7, Wallaman Falls, via Ingham, 1.x.1980, G. Monteith, 500 m RF, pyrethrum. PAPUA NEW GUINEA: 4ɗ 20Ψ, RBIN, Baiteta Forest, 5°01'S 145°45'E, 1993–96, canopy fogging. Material of doubtful identity: INDONESIA: Kalimantan: 2 Ψ, RMNH (ex coll. CLD), Tumbang Tahai, 2°02'S 113°35'E, 3–11.ix.85, Suh. Djojosudharmo, primary moist forest; Ψ, RMNH (ex coll. CLD), Kaharian, 2°02'S 113°40'E, 2–16.ix.85, Suh. Djojosudharmo, swampy primary forest, foliage.

Comments. The female discussed here as the type of H. incanescens is believed to be that of E. Simon (1895). As discussed under D. albida , the type locality in the specimen vial does not match that given in the original publication, where it is Kandy. There are two registration numbers with the H. incanescens specimen. The number used by MNHNP on the loan form is given above. The middle digit on the other label (probably Simon’s label, which also carries the locality “Galle!”) is not clear, but looks more like a ‘2’.

Diagnosis. Male. Palpal bulbus almost twice as long as wide, embolus without spine-like apophysis ( Figs 43, 44 ).

Female. Abdomen bilobed apically in dorsal view ( Fig. 47 ), strongly constricted below apical tubercles; epigynum posterior margin indented medially in ventral view ( Fig. 50 ).

Description. Male (RMNH.ARA.11302). Carapace: length 1.00 (range 0.88–1.08), width 0.82, height 0.55; strongly humped in lateral view ( Fig. 38 ), little differentiation between caput and posterior part (some other males more similar to other species), caput sides sloping in dorsal view ( Fig. 40 ), anterior margins of carapace squared, but with small protrusions in some New Guinea males. Chelicerae ( Figs 38, 42 ): small, angled cheliceral ledge; two distinct promarginal cheliceral teeth, 6 (right) or 5 (left) medium and small teeth scattered intermediately and on retromargin (right side with three small teeth apparently in a transverse row across groove), other males equally variable, one appears to have 5 retromargin teeth on one side but none at all on the other. Labium: labial spur strongly produced ( Fig. 38 ). Sternum ( Figs 38, 41 ): slightly convex, but less so than in D. deelemanae . Eyes ( Figs 38, 40, 42 ). AME: 0.10, PME: 0.06, ALE: 0.075, PLE: 0.065, AME–AME: 0.03, AME–ALE: 0.035, PME–PME: 0.03, PME–PLE: 0.07, ALE–PLE: 0.01; outline of tapeta clearly visible in secondary eyes. Legs ( Fig 38 ): I: 4.75, II: 4.04, III: 2.10, IV: 2.53; anterior femurs with three dorsolateral macrosetae distally, 2 prodorsal, 1 retrodorsal. Abdomen ( Figs 38, 39 ): length 1.45, width 0.76; apex rounded; post-genital mound not developed. Palpal organ ( Figs 13–16 , 43–45 ): palpal femur 0.29× carapace length; patella without macroseta, tibia c. 2× as long as wide; embolus gently tapering to blunt tip, embolic apophysis spoon-shaped distally, stem longer and more strap-like than D. mandibularis ; conductor, embolus and apophysis all more elongate than in D. mandibularis ; bulbus width: length = 1:1.8. Colour in alcohol: almost entirely pale creamy white and semi translucent in parts; PME with black around margins; faint trace of inverted arrow-head on sternum ( Fig. 41 ); dorsal abdomen with traces of dark pigment posteriorly.

Female (holotype). Carapace: length 1.25 (range 1.00–1.25), width 1.02, height 0.63; in lateral view rather similar to male with caput poorly differentiated from posterior ( Fig. 46 ), rather broad posteriorly in dorsal view, caput region short ( Fig. 48 ); some other females are more similar in carapace shape to other species. Chelicerae: promargin with two definite teeth plus large intermediate where rows meet ( Figs 9, 10 , intermediate arrowed), retromargin with one large and 4 small teeth grouped distally ( Fig. 10 ). Labium: rounded ( Fig. 8 ), mounded on anterior face. Maxillae with serrula ( Fig. 8 ). Sternum: convex, but less pronounced than in D. deelemanae . Eyes ( Figs 46, 48 ): AME: 0.11, PME: 0.09, ALE: 0.09, PLE: 0.08, AME–AME: 0.035, AME– ALE: 0.05, PME–PME: 0.03, PME–PLE: 0.06, ALE–PLE: 0.015; no reflective tapeta present in type, but visible in all secondary eyes of several recently collected females from New Guinea and Queensland; lateral eyes are close in all specimens, but eye position varies both vertically and horizontally. Legs ( Fig. 46 ): I: 4.75, II: 4.20, III: 2.22, IV: 2.78; distal macrosetae missing, no indication of any prolateral macrosetal bases. Abdomen ( Figs 46, 47 ): length 2.53, width 1.39; apically rather more constricted than D. raveni , and many New Guinea specimens are narrower still; post genital mound well developed as a rounded bulge, but less distinct in some other specimens. Epigyne ( Figs 50, 51 ): posterior margin broadly indented, copulatory openings hidden in ventral view; in posterior view the internal margins of the lateral plates converge towards the copulatory openings. Internal genitalia ( Fig. 52 ): copulatory ducts pass spermathecae medially, entering posteromedially into lower lobe of spermatheca; spermatheca head globular-ovate. Colour in alcohol: carapace creamy-white, eye region and chelicerae with olive markings, sternum with dark mark. Legs cream with olive-brown annulations, incomplete on femora. Abdomen dorsum pale except for brown patch anterior to anal tubercle and remains of paired markings towards anterior; brown lateral patches; ventrally with olive-brown over post-genital mound, outlined with white lines. The New Guinea females consistently have a slightly different carapace pattern with more brown or black on the caput ( Fig. 49 ) and the brown bar anterior to the spinnerets on the dorsal abdomen becomes black laterally, persisting as black spots in nearly every specimen. The Queensland females are either bleached or in poor condition, but appear to more closely match the holotype colour pattern.

Specimens of doubtful identity. The female specimens examined from Kalimantan have rather shorter copulatory ducts ( Fig. 53 ), no male is available from this area.

Distribution. Dolichognatha incanescens occurs from Sri Lanka to north-eastern Australia.

Figures

FIGURES 1 – 7. Dolichognatha incanescens female (RBIN). 1 – 4, spinnerets. 1, spinneret field, left side. 2, ALS. 3. PMS. 4, PLS (right side, image reversed). 5 – 7, legs. 5, dorsal tarsus, left leg IV. 6, tarsal organ, left leg 1. 7, tarsal claws, left leg I.

FIGURES 8 – 12. Dolichognatha incanescens female (RBIN). 8 – 11, mouthparts. 8, labium, maxillae and chelicerae. 9, right chelicera, anterior view, showing promarginal teeth; large intermediate tooth arrowed. 10, right chelicera, posteroventral, showing retromarginal teeth; large intermediate tooth arrowed. 11, right chelicera, lateral. 12, tarsal claw, left palpus.

FIGURES 13 – 16. Dolichognatha incanescens male (QM S 74356), left palpal organ (partially expanded). 13, retroventral. 14, retrolateral. 15, tarsal organ and arc of macrosetae. 16, cymbial basal process and paracymbium.

FIGURES 38 – 45. Dolichognatha incanescens male (RMNH. ARA. 11302). 38, lateral habitus; prominent cymbial basal process arrowed. 39, dorsal abdomen. 40, carapace, dorsal. 41, sternum and endites, ventral. 42, carapace and chelicerae, frontal. 43, 44, male palpal organ, ventral, retrolateral. 45, male palpal organ, expanded (RBIN); embolic lamina arrowed. Scale lines 0.5 mm for somatic parts, 0.1 mm for genitalia.

FIGURES 46 – 53. Dolichognatha incanescens female. 46 – 48, (holotype). 46, lateral habitus. 47, abdomen, dorsal. 48, carapace, dorsal. 49, female (RBIN), carapace, dorsal. 50 – 52, female epigynum (holotype). 50, ventral. 51, posterior. 52, dorsal (internal genitalia). 53, D. incanescens? (RMNH ex Kalimantan), internal genitalia. Scale lines 0.5 mm for somatic parts, 0.1 mm for genitalia.