Acantheis kazantsevae, Fomichev & Omelko & Marusik, 2024

Acantheis kazantsevae sp. nov.

Figs 1–32 View FIGURES 1–4 View FIGURES 5–10 View FIGURES 11–19 View FIGURES 20–24 View FIGURES 25–30 View FIGURES 31–32

Types. 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 GoogleMaps .

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 View FIGURES 11–19 , 20–21 View FIGURES 20–24 ) ( vs. AE absent) and epigyne with short anchor-shaped septal base ( SB) ( Figs 22 View FIGURES 20–24 , 25 View FIGURES 25–30 ) ( vs. high, square, trapezoidal or elliptical SB).

Description. Male ( Figs 1–2 View FIGURES 1–4 , 5–7, 10 View FIGURES 5–10 ). 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 View TABLE 1 . For palp and leg spination see Table 2.

Male palp as shown in Figs 11–21 View FIGURES 11–19 View FIGURES 20–24 . 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 View FIGURES 1–4 , 8–9 View FIGURES 5–10 ). 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 View FIGURES 20–24 ).

For palp and legs measurements see Table 3 View TABLE 3 . For palp and legs spination see Table 4.

Epigyne and internal genitalia as shown in Figs 22 View FIGURES 20–24 , 25–30 View FIGURES 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 View FIGURES 31–32 ).