Bifurcia dersuuzalai Fomichev et Omelko, 2021

Fomichev, A. A. & Omelko, M. M., 2021, A new species of the genus Bifurcia (Aranei: Linyphiidae) from Primorsky krai, Russa, Far Eastern Entomologist 435, pp. 20-24 : 21-24

Bifurcia dersuuzalai Fomichev et Omelko , sp. n.

http://zoobank.org/NomenclaturalActs/ 574437BE-9193-4703-B33B-F636484BECBF

Figs 1–13

TYPE MATERIAL. Holotype – ♀ ( ISEA 001.8672 ), Russia: Primorsky krai, SikhoteAlin Mts, Alekseevsky Mt. Range, Olkhovaya Mt. , 43°20.432’N, 133°39.441’E, scree,

1460–1600 m, 3.VII 2019, leg. A.A. Fomichev. Paratype: ♂ ( ISEA 001.8673 ), together with the holotype .

view; 3 – dorsal view. Scale = 1 mm.

DESCRIPTION. Female (holotype). Total length 3.68. Carapace: 1.65 long, 1.25 wide.

Carapace, maxillae and all limbs yellow. Sternum and labium yellow grey. Abdomen dorsally dirty white in the anterior part, grey in the posterior part, bearing four light transverse stripes. Venter of the abdomen grey. Spinnerets grey. Stridulatory ridges (Sr) well visible.

Chelicera with 3 teeth on promargin. Measurements of legs: I: 3.05, 0.5, 3.1, 3.03, 1.63

(11.31). II: 2.88, 0.5, 2.8, 2.78, 1.48 (10.44). III: 2.4, 0.45, 2.05, 3.08, 1.03 (9.01). IV: 3.03,

0.43, –, –, – (?). Leg spination: I: Fe p1; Pa d1; Ti d2 p2 r2 v4; Mt d2 p2 r1 v1. II: Pa d1; Ti

d2 p2 r2 v4; Mt d2 p1 r1. III: Pa d1; Ti d2 p2 r2 v1; Mt d1 p1 r1. IV: Fe 0; Pa 0; metatarsus and tarsus are lost. Epigyne as in Figs 10–13 . Scape very long, as long as postgastral part of abdomen, twisted on one full turn; distal part of the scape twice as thick as proximal part

(Ps); posterior projection long, bent dorsally, its length is 1/3 of the length of expanded distal part of the scape; lateral pockets (Lp) deep; posterior median plate (Pm) ellipsoidal.

lateral view; 6 – anterior view. Abbreviations: Sr – stridulatory ridges. Scale = 0.2 mm.

Male (paratype, non-molted specimen). Total length 3.35. Carapace: 1.45 long, 1.25 wide.

Carapace and maxillae yellow. Chelicerae light brown. Sternum and labium brown grey. Palps and legs dirty yellow. Abdomen cream-grey, darker ventrally, dorsally bears three longitudinal rows of white spots. Spinnerets yellow-grey. Stridulatory ridges (Sr) well visible. Chelicera with 3 teeth on promargin. Measurements of legs: I: 2.48, 0.43, 2.4, 2.3, 1.43 (9.04). II: 2.33,

0.43, 2.15, 2.08, 1.25 (8.24). III: 1.88, 0.38, 1.55, 1.55, 0.9 (6.26). IV: 2.38, 0.4, 2.1, 2.05,

1.13 (8.06). Leg spination: I: Fe p1; Pa d1; Ti d2 p2 r2 v5; Mt d1 p1 r2. II: Pa d1; Ti d2 p2 r2

v4; Mt d1 p1 r1. III: Pa d1; Ti d2 p1 r1; Mt d1 p1 r1. IV: Pa d1; Ti d2 p1 r2; Mt d1 p1 r1.

Male palp as in Figs 7–9 . Paracymbium wide, 3.5 times wider than tibia; dorsal outgrowth (Do)

massive, hooked; finger-like anterior extension (Fl) nearly straight, bent dorsally; ventral outgrowth (Vo) bent retrolaterally. Embolic division underdeveloped in non-molted specimen.

DIAGNOSIS. The new species is closely related to B. maritima and B. oligerae , which are also known from the Russian Far East. All three species have scape longer than high with expanded distal part (Ds). Female of B. dersuuzalai sp. n. can be distinguished from both sibling species by the distal part of the scape almost as long as high vs. longer than high

(length/height ratio 0.8 in the new species and 2.0– 2.9 in sibling species). Besides, the new species can be separated from B. oligerae and B. maritima by the posterior projection of the scape (Pp) located almost at right angle (see dotted lines at Fig.11 ) to the expanded distal part of the scape (vs. posterior projection and expanded distal part being stretched in a straight line) (cf. Fig 11 and figs 11, 14 in Marusik et al., 2016). The male of the new species differs from all congeners with the exception of B. maritima by the hook-shaped dorsal outgrowth

(Do) of the paracymbium (Pa) (vs. straight). The male of B. dersuuzalai sp. n. can be separated from that of B. maritima by the finger-like anterior extension of the paracymbium (Fl) shifted ventrally (vs. located midway between dorsal and ventral (Vo) outgrowths of the paracymbium)

(cf. Fig. 8 and fig. 1 in Tanasevitch, 2010).

DISTRIBUTION. Known only from the type locality.

lateral view; 8 – retrolateral view; 9, 12 – ventral view; 10 – dorsal view; 11 – lateral view;

13 – posterior view. Scale = 0.2 mm. Abbreviations: Do – dorsal outgrowth of the paracymbium, Ds – expanded distal part of the scape, Fl – finger-like anterior extension of paracymbium, Lp – lateral pockets, Pa – paracymbium, Pm – posterior median plate, Pp – posterior projection, Ps – proximal part of the scape, Vo – ventral outgrowth of the paracymbium.

COMMENTS. The female was selected as the holotype primarily because it is more clearly differentiated from its congeners. Another reason is that the male specimen is nonmolted, with underdeveloped sclerites of the palp.

ETYMOLOGY. The specific name is a patronym in honour of Dersu Uzala (1849– 1908),

an indigenous tribesman of the Russian Far East (a member of the Nanai people), hunter,

guide and participant of expeditions of Vladimir K. Arsenyev, a prominent Russian traveler.

We wish to thank Mikhail M. Omelko senior (Gornotaezhnoe, Russia) for his help in organizing the expedition, during which the material treated here was collected. We are grateful to Yuri M. Marusik (Magadan, Russia) for commenting on the draft of the manuscript. English of the final draft was kindly checked and corrected by Victor Fet

(Huntington, USA). The research was carried out as a part of the Program for the Support of

Scientific and Pedagogical Staff of the Altai State University, the project “Biodiversity of dominant predatory arthropods of the Great Caucasus: spiders ( Arachnida: Aranei) and centipedes (Myriapoda: Chilopoda)”.

Figures

Figs 1–3. Habitus of Bifurcia dersuuzalai sp. n., male (1, 3) and female (2). 1–2 – lateral

Figs 4–6. Cephalic part of Bifurcia dersuuzalai sp. n., male (5–6) and female (4). 4–5 –

Figs 7–13. Male palp (7–9) and epigyne (10–13) of Bifurcia dersuuzalai sp. n. 7 – pro-