Knoflachia kurilensis sp. nov.

Figs 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12

Etymology.

Named after the type locality, Kuril Islands.

Material.

Holotype ♂ and allotype ♀ (ZMMU) and paratypes 144♂ 1 (♂) 77♀ (ZMMU & ZISP) with label "[KU-123] KUNASHIR Isl., CW part, S shore of Lagunnoye Lake, 44°03′05″N, 145°45′E, sweeping along road, mostly alder bushes, 24.09.1997 Yu. M. Marusik ".

Diagnosis.

Same as for the genus. Well differs from other Theridiidae occurring in East Asia by colouration (Fig. 1), epigyne with septum (Fig. 9D) and male palp with strongly enlarged tibia covering half of the bulb (Fig. 9A-C).

Description.

Male (holotype). Total length 2.4. Carapace 1.38 long, 1.08 wide; abdomen 1.45 long, 1.35 wide. Prosoma, including legs orange-reddish, legs I as dark as carapace, sternum, mouthparts, and legs II-IV lighter. Abdomen uniformly dark dorsally, venter with lighter booklung covers and area near petiolus. Palp and leg lengths as per Table 1.

Palp - see genus description.

Small male. Total length 2.13. Carapace 1.0 long, leg I 4.26 (1.38. 0.5, 1.0, 0.88, 0.5). Pattern as in holotype.

Variations. Total length varies from 1.9 to 2.5. At least one male has leg colouration like in females.

Female (allotype). Total length 2.75. Carapace 1.08 long, 1.0 wide. Carapace, sternum, mouth parts as in male. Legs I-II with dark tibiae, metatarsi and tarsi, legs III-IV with dark metatarsi and tarsi. Palps with dark tibiae and tarsi. Palp and leg lengths as per Table 2.

Variations - Total length varies from 2.25 to 2.85, colour of abdomen in alcohol from almost black to grey.

Natural history.

All specimens were collected in one day by sweeping bushes. The great number of specimens collected in a few hours most likely indicates that they may form colonies, like Anelosimus . Some specimens look like penultimate. The presence of only one subadult specimen indicates that the species is monovoltine.

Distribution.

Known from the single locality in Kunashir Island (Fig. 12).

Male polymorphism.

Males vary in size and relative length of the first leg (cf. Fig. 1C and 1D). Larger males have a relatively longer femur I (femur I/carapace length ratio ca. 1.45 in large male and 1.33 in small). Larger males have a distinct tibial and metatarsal macrosetae on legs I and II (setae standing on tegumental stump-like outgrowth Figs 2A, B, 5A). Size polymorphism is known in several groups of Theridiidae (e.g., Parasteatoda tepidariorum (C.L. Koch, 1841), Steatoda triangulosa (Walckenaer, 1802) [Nentwig et al. 2023]). Large-size polymorphism was documented in Enoplognatha monstrabilis Marusik & Logunov, 2002 (see Marusik and Logunov 2002), a species with similarly modified setae on leg I and occurring in Siberia. The carapace of the largest male is 1.7 times longer than in the smallest one. The same type of modified setae is documented in the New World Anelosimus studiosus (Hentz, 1850) (see Agnarsson 2004) and in the East Mediterranean Enoplognatha parathoracica Levy & Amitai, 1981 and E. quadripunctata Simon, 1884 (see Huseynov and Marusik 2008).