Eratigena laksao, Bolzern, Angelo & Jäger, Peter, 2015

Bolzern, Angelo & Jäger, Peter, 2015, Unexpected occurrence of the genus Eratigena in Laos with description of a new species (Araneae: Agelenidae), Zootaxa 3920 (3), pp. 431-442 : 435-438

Eratigena laksao sp. n.

( Figs 1–21 )

Paratype ♂: Laos, Bolikhamsay Prov., Lak Sao, Tham Man Kone, N 18°13’16.1”, E 104°48’45.9”, 501 m, inside cave, at day, by hand, 27.XI.2012, P. Jäger (SMF; GenBank accession number LK996041 ).

Additional material. Same data as holotype, 1 subadult female. Same data as paratype, 2 juveniles.

Etymology. The specific name is a noun in apposition taken from the type locality and can be translated as “kilometre 20”, referring to the distance of the town from the Vietnamese border.

Diagnosis. Male E. laksao sp. n. resemble those of E. vomeroi , E. inermis , and E. sicana (Brignoli, 1976) in having distinctly annulated legs ( Figs 1–4 ; all other species pale, completely darkened or only basally annulated legs). They differ from those and all other species in having a median apophysis lacking a distinct distal sclerite ( Figs 14–14 , 19–20 ), and an RTA with bristles ( Figs 14–18, 21 ).

Male. Measurements: Male (holotype larger than paratype; only carapace and abdomen measured for both): carapace length 3.98–4.60, width 2.92–3.49, abdomen length 3.94–4.73, width 1.83–2.93, sternum length 2.13, width 1.98. Leg I (femur: 8.94, patella: 1.63, tibia: 8.81, metatarsus: 10.90, tarsus: 6.20), II (7.11, 1.63, 6.59, 8.44, 4.14), III (7.23, 1.50, 6.02, 8.56, 3.40), IV (9.12, 1.66, 7.83, 12.80, 4.92). Pedipalp (1.96, 0.86, 1.04, 2.26), bulb 1.15. Eyes: PME 0.238, PLE 0.293, AME 0.249, ALE 0.279. Eye distances: PME–PME 0.5 x PME, PME–AME 0.5 x PME, PME–PLE <0.5 x PME, PME–ALE 1 x PME, AME–AME << 0.5 x AME, AME–ALE << 0.5 x AME. CLY1 2 x AME, CLY2 0.5– 1 x ALE.

Male palp ( Figs 14–21 ): Patellar apophysis absent; RTA with two branches, ventral one (vRTA) moderately protruding, bulbous, dorsal one (dRTA) originating dorsolaterally of ventral one, strongly sclerotized (black) and protruding, thorn-like, pointed; dorsolaterally of RTA with distinct field of long and thick bristles (Br); ventral ridge absent. Cymbium sharply pointed. Filiform embolus (E) about 1.5 times longer than cymbium width, originating at 10–11 o’clock position, distal tip at 4–5 o’clock position. Conductor (C) T-shaped with distal portion moderately elongated, shorter than wide, distally rounded, lateral margin folded along ¾ of conductor length. Terminal end moderately elongated, simply rounded. Connection of tegulum and conductor membranous; massive membranous ridge (R) present. Median apophysis (MA) originating at 6 o’clock position, only moderately protruding, as wide as long, membranous, distal sclerite absent.

Other important characters ( Figs 1–13 ): Cheliceral promargin with four teeth, retromargin with seven subequally sized teeth (most proximal tooth smaller). Colulus trapezoidal plate with distal margin moderately Wshaped. PLS with distal segment longer than basal segment. Tarsal trichobothria on cymbium absent. Series of tarsal trichobothria increasing in length towards tip. Leg spination: male palp (2–0–0–0, 2–0–0, 1–1–0–0 or 2–2–0–0), leg femora (2+–3–3–0, 2–1–2–0 or 3–3–4–0, 4–4–4–0, 2–1–2–0 or 3–3–3–0), patellae (all 2–0–0), tibiae (2–2–2–3 or 2–2–2–1+1p+1, 1–2–1–2 or 2–2–2–1p+1, 2–2–2–1+1p+1, 2–2–2–2 or 2–2–2–3), metatarsi (0–1–0–3p+1 or 0–2–0–3p+1, 0–2–0–3p+1 or 0–3–2–3p+1, 0–3–2–3p+1 or 0–3–3–3p+1, 0–3–2–1+1p+1+1p+1 or 0–4–4–1+1p+1+1p+1), tarsi (0, 0 or 0–2–2–0, 0–1–2–0, 0–1–2–1 or 0–1–3–1).

Colouration ( Figs 1–9 ): Carapace with two longitudinal symmetrical dark bands, margins broadly darkened, between margin and bands irregularly bright spots, median from eyes to posterior end of carapace distinct white band (white hairs), head region laterally with two distinct, longitudinally curved dark bands. Chelicerae frontally with distinct dark patches. Sternum with distinct pale median band, bordered by darkened bands. Opisthosoma dark, brownish, with reddish pale median band, anteriorly bordered by white bands, posteriorly with white dots (indistinct chevrons). Legs annulated. Colulus darkened. ALS moderately, PLS distinctly darkened (lateral segment of PLS moderately less darkened than basal one).

Female. Unknown.

Distribution. Reported from two caves in Bolikhamsay Province, Laos.

Figures

FIGURES 1 – 4. Eratigena laksao sp. n., male paratype habitus of living specimen (1 lateral view; 2 anterior view; 3 dorsal view; 4 same specimen as subadult, dorsal view).

FIGURES 5 – 13. Eratigena laksao sp. n., male holotype. 5. Carapace, dorsal view. 6. Abdomen, dorsal view. 7. Carapace and chelicerae, anterior view. 8. Sternum, ventral view. 9. Spinnerets, ventral view. 10. Chelicerae, posteroventral view. 11. Mouthpart, ventral view. 12. Coxa with trochanter and basal femora, ventral view. 13. Claws of leg 1, lateral view.

FIGURES 14 – 15. Eratigena laksao sp. n. 14. Left palp in ventral view (male holotype). 15. Same, retrolateral view. Abbreviations: Br = bristles; C = conductor; dRTA = dorsal branch of RTA; E = embolus; MA = median apophysis; R = membranous ridge; RTA = retrolateral tibial apophysis; vRTA = ventral branch of RTA.

FIGURES 16 – 21. Eratigena laksao sp. n., male holotype. 16. Left palp, prolateral view. 17. Same, ventral view. 18. Same, retrolateral view. 19. Bulb of left palp, ventral view. 20. Same, retrolateral view. 21. Palpal tibia, dorsal view.