Nesiergus halophilus Benoit 1978

Guadanucci, José Paulo L. & Gallon, Richard C., 2008, A revision of the spider genera Chaetopelma Ausserer 1871 and Nesiergus Simon 1903 (Araneae, Theraphosidae, Ischnocolinae), Zootaxa 1753, pp. 34-48 : 44-46

Nesiergus halophilus Benoit 1978

Figures 29–34

Nesiergus insulanus: Hirst 1911: 383 (Ψ). Misidentification.

Nesiergus halophilus Benoit 1978: 412 , figs. 4a–e (D♂Ψ); Smith 1990: 133, figs. 861–877 (♂Ψ); Schmidt 1993: 57, figs. 31–32 (♂Ψ).

Material examined. Type material: Holotype Ψ ( MRAC 145439) from Frégate, Seychelles, 10.VIII.1972; Paratypes 1ɗ ( MRAC 143293), 2Ψ 1 imm. ( MRAC 143297) from Frégate, Seychelles, 10.VIII.1972; Paratypes 3Ψ, 3 imms. ( MRAC 143272) from Laraie Bay, Curieuse, Seychelles, 3 and 17.VIII.1972. All examined.

Additional material examined: 1Ψ, ( BMNH 10.5.1.4), from the Seychelles, Percy Sladen Trust Expedition leg.

Diagnosis: Males differ from those of N. gardineri by the presence of a distinct embolic keel ( Figs. 30– 32 ), by the prolateral branch of the tibial apophysis being wide and rounded ( Figs. 33 ) and by metatarsus IV being curved laterally. Females differ from those of N. gardineri by spermathecal morphology ( Fig. 34 ).

Note: very likely to be a junior synonym of N. insulanus ; however the species should remain valid pending examination of additional material.

Description: Female (holotype). Total length 13.6. Carapace length 5.2, width 3.7. Eye tubercle: length 0.8, width 1.0; anterior row procurved, posterior row slightly recurved, clypeus absent. Labium length 0.7, width 1.0. Sternum length 2.2, width 2.2. Chelicerae with 8 teeth of similar size on promargin. Labium as long as wide with ca.50 cuspules. Maxillae with ca. 60 cuspules. Sternum rounded. Fovea transverse. Palp: femur 2.6/ patella 1.8/ tibia 1.6/ tarsus 1.7/ total 7.7. Legs I: femur 3.8/ patella 2.5/ tibia 2.7/ metatarsus 2.2/ tarsus 1.6/ total 12.8. II: 3.2/ 2.2/ 2.1/ 2.0/ 1.3/ 10.8. III: 2.8/ 1.7/ 1.6/ 2.2/ 1.5/ 9.8. IV: 4.2/ 2.2/ 3.2/ 3.6/ 1.9/ 15.1. Spines. Palpal and leg femora with medial row of thick setae. Palp: tibia (v) 0–0–ap1. Legs I: metatarsus (v) 0–0–ap 1. II: metatarsus (v) 0–0–ap 1. III: patella (p) 1, tibia (r) 1–1–0, (p) 0–2–0, (v) 2–0–ap2, metatarsus (r) 0–1–1, (p) 0–2–1, (v) 2–0ap 3. IV: tibia (r) 1–1–0, (v) 2–0–ap3, metatarsus (r) 0–1–1, (p) 0–1–1, (v) 1–3–ap3. Spermathecae comprising two receptacula, each longer than wide and broader than in N. insulanus ( Fig. 34 ). Metatarsal scopulae extent (ventral surfaces only): I–II along entire length; III on slightly less than distal half; IV on distal third. Tarsal scopulae (ventral surfaces only): I–II undivided; III–IV divided by longitudinal band of thick setae.

Male (paratype MRAC 143.293). Total length 17.0. Carapace length 7.2, width 5.2. Eye tubercle length 0.9, width 1.1; anterior row procurved, posterior row slightly recurved, clypeus absent. Labium length 0.7, width 1.1. Sternum length 2.9, width 2.6. Chelicerae with 10–12 teeth of similar size on promargin. Labium as long as wide with ca. 50 cuspules. Maxillae with ca. 60 cuspules. Sternum rounded. Fovea transverse. Palp: femur 3.6/ patella 2.3/ tibia 2.7/ cymbium 1.4/ total 10.0. Legs I: femur 5.6/ patella 3.8/ tibia 5.1/ metatarsus 4.6/ tarsus 3.0/ total 22.1. II: 5.1/ 3.3/ 4.1/ 4.7/ 3.0/ 20.2. III: 4.9/ 2.6/ 3.3/ 5.1/ 2.7/ 18.6. IV: 6.3/ 2.9/ 5.1/ 5.4/ 3.1/ 22.8. Spines. Palpal and leg femora with medial row of thick setae. Palp without spines. Legs I: femur (d) 0–0–2, tibia (p) 0–1–1, (v) 0–1–0, metatarsus (v) ap 1. II: femur (d) 0–1–1, patella (p) 1, tibia (p) 0–1–1, (v) 1– 0–ap2, metatarsus (v) 1–0–ap 2. III: femur (d) 0–2–2, patella (p) 1, (r) 1, tibia (p) 1–1–0, (r) 1–1–0, (v) 2–2– ap3, metatarsus (p) 0–1–1, (r) 0–1–1, (v) 4–2–ap 3. IV: femur (d) 0–2–2, (r) 1, tibia (p) 1–1–0, (r) 1–1–0, (v) 3–3–ap3, metatarsus (p) 1–1–1, (r) 1–1–1, (v) 3–3–ap3. Palpal bulb with tapering embolus, slightly spiralled, bearing keel along embolus ( Figs. 30–32 ). Tibial apophysis comprising two branches, strongly fused basally ( Fig. 33 ). Prolateral branch short, wide, apically rounded, with adjacent strong, short spine. Retrolateral branch long, thin, with apical row of 5–6 short spines, and short curved spine on inner side. Metatarsus I straight, bends externally to tibial apophysis. Metatarsi I–IV laterally curved. Metatarsal scopulae extent (ventral surfaces only): I along entire length; II on distal three-quarters; III on distal half; IV on distal quarter. Tarsal scopulae (ventral surfaces only): I–II undivided; III–IV divided by longitudinal band of thick setae.

Distribution: Known from Frégate, Silhouette, Récif and Curieuse, Seychelles.

Ecology: Spiders inhabit sandy beaches where they construct vertical burrows in the sand, beneath rocks and coral fragments. The burrows were situated just above the mean spring tide level, at the upper limit of the crab-hole zone ( Benoit 1978). Males are mature in August.

Figures

FIGURES 29 – 34. Nesiergus halophilus (Benoit 1978) (holotype female MRAC 145439; paratype male MRAC 143.293). 29. Habitus, dorsal view, male. 30 – 32. Palpal bulb, prolateral view (30), retrolateral view (31), dorsal view (32). 33. Male tibial apophysis, ventral-prolateral view. 34. Spermathecae, dorsal view. Scale = 1 mm.