Acantheis kazantsevae Fomichev, Omelko & Marusik, 2024, sp. nov.

Overview & Synopsis

Acantheis kazantsevae sp. nov.Figs 1–32Types. INDONESIA: Sumatra Island:Aceh Prov.: holotype ♂ (ISEA, 001.9097), Ketambe Vil. [03°41′N, 97°39′E], 400–500 m, under stones in pristine forest, 1988 (precise date unknown), unknown collector. Paratype: 1♀ (ISEA, 001.9098), with same data as for holotype.Etymology. The specific name is a matronym in honor of Yulia G. Kazantseva (Novosibirsk, Russia), talented psychiatrist and friend of the senior author.Diagnosis. The new species differs from all other species of Acantheis by having a twisted tegular apophysis with two arms: a large boomerang-shaped anterior one (AT) and a posterior one (PT) (vs. tegular apophysis not twisted), embolus with long pointed arm (AE) (Figs 16–17, 20–21) (vs. AE absent) and epigyne with short anchor-shaped septal base (SB) (Figs 22, 25) (vs. high, square, trapezoidal or elliptical SB).Description. Male (Figs 1–2, 5–7, 10). Total length 4.25. Carapace: 2.1 long, 1.8 wide. Opisthosoma: 2.1 long, 1.4 wide. Carapace yellow-gray with yellow median band. Clypeus brown-gray. Chelicerae, labium, endites, sternum, and coxae yellow. Palps and legs dirty-yellow. Abdomen yellow-gray, with yellow median band dorsally. Venter of opisthosoma yellow. Spinnerets yellow-gray. Cephalic part with a tuft of long, light setae between PME.Eye sizes and interdistances: AME 0.14, ALE 0.09, PME 0.23, PLE 0.23; AME–AME 0.07, AME–ALE 0.13, PME–PME 0.09, PME–PLE 0.1, AME–PME 0.09, ALE–PLE 0.11. Clypeus height at AME 0.20, at ALE 0.39. Chelicerae with 3 promarginal and 5 retromarginal teeth. Femur I/carapace length ratio 1.57.For palp and leg measurements see Table 1. For palp and leg spination see Table 2.Male palp as shown in Figs 11–21. Femur 5.3 times longer than wide. Patella 2.0 times longer than wide. Tibia ca. 2.2 longer than wide, with 3 very long spines, longest ca. 0.9 of tibia length. Retrolateral tibial apophysis (RTA) shorter than tibia diameter, with rounded anterior part, with 2 small spines. Ventral tibial apophysis (VTA) larger than RTA. Cymbium spineless, ca. 2.4 times longer than wide. Cymbial tip about 0.42 of cymbial length, slightly shorter than bulb. Subtegulum (St) large, oval. Tegulum ca. 1.2 times longer than wide. Tegulum (T) with prolateral extension (TE). Spermophor (Sf) encircling the entire tegulum. Posterior arm of tegular apophysis (PT) ear-shaped, with a deep cavity (TC) at base of anterior arm (AT). AT large, boomerang-shaped.Apical part of AT retrolaterad and basal part with large, ventral extension (VE). Basal part of AT bulged and apical one with distinct ridges ventrally. Conductor (C) membranous, elliptical. Basal part of embolus (E) with ventrad bulge (VB) and proximad spur (ES). Embolic arm (AE) almost straight, longer than embolic tip (ET), protruding from retrolateral side of embolus. Embolic tip straight, about 0.7 of embolic arm length.Female (Figs 3–4, 8–9). Total length 5.35. Carapace: 2.45 long, 2.0 wide. Opisthosoma: 2.8 long, 1.95 wide. Carapace and clypeus as in male. Chelicerae, endites and labium yellow brown. Sternum and coxae as in male. Palps, legs, opisthosoma and spinnerets as in male. Cephalic part with a tuft of long light setae between PME. Eye sizes and interdistances:AME 0.16, ALE 0.11, PME 0.29, PLE 0.23; AME–AME 0.1, AME–ALE 0.17, PME–PME 0.11, PME–PLE 0.14, AME–PME 0.1, ALE–PLE 0.14. Clypeus height at AME 0.19, at ALE 0.39. Chelicerae with 3 promarginal and 5 retromarginal teeth. Femur I/carapace length ratio 1.27. Femur I with one row of flexible ventral spines equipped with locking mechanism (Figs 23–24).For palp and legs measurements see Table 3. For palp and legs spination see Table 4.Epigyne and internal genitalia as shown in Figs 22, 25–30. Epigynal plate 1.6 times wider than long. Septal base (SB) anchor-shaped. Septal stem (SS) 1.5 times shorter than septal base width. Lateral teeth (LT) distinct, almost parallel in posterior view. Receptacles (Re) circular, subdivided into 2 chambers: flattened chamber I (ReI) and elliptical chamber II (ReII). Copulatory ducts (CD) very short, tightly pressed to ReI.Distribution. Known from the type locality only (Figs 31–32).