Caucaseuma variabile Antić & Makarov, 2016, sp. nov.

Caucaseuma variabile sp. nov.

Figs 38–42

Diagnosis. Differs from the other Caucaseuma species by the special features of anterior shields and posterior processes of the gonopods, as well as in the presence of 28 body segments in adults (including telson).

Etymology. To emphasize the presence of a variable posterior lever of the anterior gonopods.

Material studied (total: 10 males, 7 females). Holotype. RUSSIA: male, North Ossetia, S of Alagir, 700 m asl, Acer, Fagus etc., forest, litter, 17 Oct. 1987, S. Golovatch leg. (ZMUM ρ3284).

Paratypes (total: 4 males, 4 females). All from RUSSIA, North Ossetia, near Alagir: 3 females, same data as holotype (ZMUM ρ3285); 1 male, Fagus litter, 1700 m asl, 21 Aug. 1983, O.A. Gvozdeva leg. (ZMUM ρ3286); 1 male, Fagus, 1800 m, 27 Aug.1983, O.A. Gvozdeva leg. (ZMUM ρ3287); 1 male, Pinus, 1800 m asl, 26 Aug. 1983, O.A. Gvozdeva leg. (IZB); 1 male, 1 female, 1700 m asl, Fagus, 13 Aug.1984, O.A. Gvozdeva leg. (ZMUM ρ3288).

Other material (total: 5 males, 3 females). RUSSIA: 1 male, Krasnodar Province, Sochi, Khosta, Taxus & Buxus grove, Apr. 2006, Y. Chumachenko leg. (ZMUM ρ3289); 2 males, 1 female, same data, except: Mar. 2006 (ZMUM ρ3290); 1 male, 1 female, Stavropol Province, Stavropol Botanical Garden, 10 Apr. 2014, R. Zuev leg. (ZMUM ρ3291).

GEORGIA: 1 male, 1 female, Mtskheta-Mtianeti, Step’antsminda: church Tsminda Sameba towards Ortsveri glacier, long, ungrazed alpine meadow, 7 Oct. 2012, F. Walther leg. (IZB).

Type locality. RUSSIA: North Ossetia, near Alagir.

Description. Body with 28 segments (including telson) in adults.

MEASUREMENTS. Males 8–11 mm long, vertical diameter of the largest pleurotergite 0.75–0.80 mm. Females 10–11 mm long, vertical diameter of the largest pleurotergite 0.90–0.95 mm.

COLORATION (Fig. 38). Dorsal and lateral sides greyish, remaining parts pale yellowish. Some specimens almost completely greyish.

HEAD. Without frontal depression in males. Labrum with three medial teeth and 5+5 labral and 3+3 supralabral setae. Promentum triangular, without setae. Lingual plates with 6+6 setae. Stipites with 1+1 long apical setae; 4+4 marginal setae; 13+13 medial and basal setae. Antennae 1.50 mm long in holotype. Length of antennomeres (in mm): I (0.04), II (0.13), III (0.40), IV (0.2), V (0.41), VI (0.17), VII (0.13) and VIII (0.02). Length/breadth ratios of antennomeres I–VII: I (0.8), II (1.6), III (4.9), IV (2.2), V (3.7), VI (1.6) and VII (1.6). Antennomeres II, IV, V, VI and VII with one, three, one, four and one sensillum, respectively. Number of ocelli 16–20, arranged in 5–6 rows in males; 16–19 in 5–6 rows in females.

COLLUM. Narrower than head, with six macrochaetae.

BODY SEGMENTS (Figs 38, 39). Lateral keels like lateral swellings, better developed in males. Macrochaetae relatively long and trichoid. CIX (pleurotergite 15) ~ 0.6; MIX (pleurotergite 15) ~ 1.4; PIX (pleurotergite 15) ~ 0.4; MA (pleurotergite 15) ~ 123˚.

TELSON. Epiproct with a pair of spinnerets and 3+3 setae (1+1 paramedian, 2+2 marginal). Hypoproct with 1+1 apical setae. Paraprocts with 3+3 marginal setae.

WALKING LEGS. In both sexes, leg-pairs 1 and 2 with tarsal combs; prefemora with several long and robust setae; femora and postfemora with a group of several long and robust setae.

MALE SEXUAL CHARACTERS (Fig. 40). Leg-pairs 3–7 enlarged. Leg-pairs 3 and 4 each with a basal external protrusion on prefemur. Leg-pairs 5–7 without any peculiarities. Leg-pairs 10 and 11 with coxal glands; without other peculiarities.

ANTERIOR GONOPODS (Figs 41 A–C, 42). Anteriorly, sternal plate (sp) [= v sensu Strasser (1970): 201, figs 1 and 2] with a medial, triangular, hairy, tapering, sternal sac (ss) [= s sensu Strasser (1970): 201, figs 1 and 2]. Anterior coxal processes (cp) [= sc sensu Strasser (1970): 201, figs 1 and 2] shield-like, wide, partially fused, divided distally. Mesal edges folded inside and forming a posterior projection (ppr). At lateral to mesal edges, a more or less subtriangular thickening (st) present, curved posteriorly. In distal view this thickening forming a Ushaped rift with mesal edges. Anterior coxal processes fused with posterior coxal processes (pp) [= te sensu Strasser (1970): 201, 202, figs 2 and 3]. Posterior coxal processes (pp) starting with a subtriangular anterior horn (ah) [= z sensu Strasser (1970): 201, 202, figs 1–3] which fits in the depression lateral to the subtriangular thickening of the anterior coxal process. Anterior horn connected to a lever (lv) by a denticulated lamella (dl). Levers curved mesad in posterior view, divided distally into two fingers: a lateral, exterior finger (ef) bare or with only a few spines, and a mesal, inner finger (if) covered by numerous spinules. Posteriorly at mesal edges of levers, a longitudinal thickening present, connected distally to mesal, inner part of lever (ilv) and forming together an opening (o) with a possible function in sperm transfer. Posteriorly, levers covered by groups of numerous setae (rs). Between and inside anterior and posterior coxal processes, two lobes visible which possibly represent remnants of coxal vesicles (cv) [= w sensu Strasser (1970): 202, fig 3]. At base of posterior coxal processes, telopodital (t) remnants can be seen, yet only in the form of a small pigmented mass.

POSTERIOR GONOPODS (Figs 41 D, 42C–E). Similar to other Caucaseuma.

Distribution. Russia, Georgia (Fig. 168, blue circle).

Notes. This species shows a remarkably wide, but disjunct distribution and, according to the structure and length of the distal fingers of the posterior levers of the anterior gonopods, can be divided into three populations. One occurs near Khosta, Sochi, and is characterized by the presence of short and thick lateral and mesal fingers of the posterior lever which form short pincers. The second population occurs south of Alagir and near Ortsveri glacier and is characterized by the presence of somewhat longer lateral and mesal fingers of the posterior levers which fail to form pincers, but placed almost at 90˚ to each other. The third population inhabits the botanical garden in Stavropol and is characterized by the presence of long and slender lateral and mesal fingers which do form long pincers.

Bearing in mind that all seven species of the genus Caucaseuma differ clearly from each other (including C. variabile sp. nov.) and that all, except C. variabile sp. nov., show narrower distributions, on the one side, and that the Caucasian Anthroleucosomatidae (with more analyzed males) fail to show either intra- or interpopulation variability (except C. variabile sp. nov. and Paranotosoma cordatum gen. et sp. nov.), on the other hand, it may be that we are dealing with a taxon in a stage of allo- or parapatric speciation. Of course, future research will show whether we were right or wrong.