Caucaseuma strasseri Antić sp. nov.

urn:lsid:zoobank.org:act: 07997368-20D0-4C1A-A0E2-872B0054D969

Figs 1–6, 7H

Diagnosis

Caucaseuma strasseri Antić sp. nov. is the only species in the genus characterized by the presence of anterior triangular processes on the angiocoxites of the anterior gonopods.

Etymology

The new species is named after the late Carlo Strasser (1903–1981), a well-known and always inspiring diplopodologist, who made an immeasurable contribution to the knowledge of European millipedes. At the same time, Strasser described the first cave chordeumatidan taxon from the Caucasus, Caucaseuma lohmanderi . A noun in the genitive case.

Material examined (7 ♂♂, 4 ♀♀, 30 juvs)

Holotype RUSSIA • ♂; Western Caucasus, Krasnodar Province, Greater Sochi, near Lazarevskoye, Kirovskaya (= Tigrovaya) Cave; 2 May–12 Aug. 1996; A.G. Koval leg.; Barber pitfall traps; ZMUM.

Paratypes RUSSIA • 1 ♂ (used for SEM); same collection data as for holotype; NHMW MY10260 • 4 ♂♂ (2 without posterior body rings); same collection data as for holotype; ZMUM • 1 ♂ (without posterior body rings); same collection data as for holotype; IZB • 1 ♀; same collection data as for holotype; ZMUM .

Other material

RUSSIA • 2 ♀♀ (without posterior body rings); same collection data as for holotype; IZB • 1 ♀ (without posterior body rings); same collection data as for holotype; ZMUM • 30 juvs (12 without posterior body rings); same collection data as for holotype; IZB .

Description

SIZE AND NUMBER OF BODY RINGS. Body in adults with 30 rings (including telson). Holotype male 20 mm long, vertical diameter of largest ring 1.35 mm. Paratype males 16.5–17 mm long, vertical diameter of largest ring 1.3 mm. Paratype female 18.5 mm long, vertical diameter of largest ring 1.6 mm.

COLORATION (Fig. 2). After more than two decades in ethanol yellowish. Ommatidia brownish (Fig. 2B– C).

HEAD (Figs 2B–C, 3A–E). Setose, frontal side convex in both sexes. Labrum with three medial teeth and 4+4 or 6+6 labral and 2+2 supralabral setae (Fig. 3B). Promentum triangular, without setae. Lingual plates with 6+7 setae arranged in irregular row. Stipites with ca 30 setae each. Antennae 3.1 mm long in holotype male. Length of antennomeres (in mm): I (0.11), II (0.30), III (0.88), IV (0.43), V (0.85), VI (0.30), VII (0.22) and VIII (0.04). Length/breadth ratios of antennomeres I–VII: I (1), II (2), III (7), IV (3), V (6), VI (2) and VII (2). Antennomeres II, IV, V, VI and VII with one, three, one, four and one sensillum trichoideum, respectively (Figs 2B, 3A). Antennomeres V and VI distally with sensilla basiconica (Fig. 3D–E). Lateral to antennal sockets a group of papillae-like outgrowths present (Fig. 3C). Number of ommatidia: 20–25 (mainly 23) in 6 rows in both sexes, arranged in irregular subtriangle (Figs 2C, 3C).

COLLUM. Narrower than head, with six macrochaetae, as all body rings. Anterior edge semi-circular, posterior margin gently concave.

BODY RINGS (Figs 2A–B, D–E, 3G–H). Lateral keels well-developed. Macrochaetae long and trichoid (Fig. 4E–F). CIX (ring 15) ~ 0.7; MIX (ring 15) ~ 1.2; PIX (ring 15) = 0.6; MA (ring 15) ~ 105°. Prozonites with hexagonal tiles. Metazonites with scale-like structures.

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

LEG- PAIRS 1 AND 2 (Figs 3F, 4A–B). In both sexes, femora, postfemora and tibiae with long and robust setae; tarsi with comb of setae.

MALE SEXUAL CHARACTERS (Figs 2B, 4). Leg-pair 2 with genital openings on coxae (Fig. 4B). Leg-pairs 3–7 enlarged. Leg-pairs 3 and 4 each with a basal external protrusion on prefemur (Fig. 4C–D). Legpairs 5 and 6 without peculiarities (Fig. 4E–F). Leg-pair 7 with ventral side of coxae densely setose, with a shallow excavation posteriorly; ventral side of prefemora densely tuberculated; tarsi elongated (Fig. 4G). Leg-pairs 10 and 11 with coxal sacks; no other peculiarities (Fig. 4H–I).

ANTERIOR GONOPODS (Figs 5A–C, 6A–F, 7H). Gonopodal sternum (S) well-developed, wide, with anterior triangular, long sternal process (Sp) covered with hair-like outgrowths. Anterior parts (aA) of angiocoxites shield-like, medially completely fused, only with anterior furrow, almost fully rounded in anterior view; subdistally with a pair of notches and short, lateral, bone-like processes (bp); distally with medial structure mushroom-shaped in anterior view with lateral margins curved posteriad; posteriorly, at site of fusion of anterior parts of angiocoxites, with a posterior projection (pp), denticulate distally, and extending between posterior parts of angiocoxites. A pair of characteristic anterior triangular (tp) processes present on angiocoxites. Posterior parts (pA) of angiocoxites in form of elongate levers in posterior view, with distal parts curved anteriad; anteriorly with additional lamellar and setose projections. Between posterior parts of angiocoxites coxal vesicles (Cv) visible.

POSTERIOR GONOPODS (Figs 5E, 6G–I). Gonopodal sternum (S) well-developed, wide, with a deep pit laterally. Coxites (Cx) divided, each with a small telopodite (T) posteriorly and coxal vesicle (Cv) and angiocoxite (A) anteriorly. A pair of flagelliform processes originating from base of angiocoxite.

Remarks

This species is known only from a cave and shows certain troglobiomorphic features such as reduced body and ommatidia pigmentation, elongated antennae and walking legs, as well as a larger and more robust body compared to epigean congeners.

Distribution

Caucaseuma strasseri Antić sp. nov. is known so far only from its type locality, Kirovskaya (= Tigrovaya) Cave (Fig. 1). This cave is the type locality of two more cave animals, viz., the troglobiontic isopod Pseudobuddelundiella ljovuschkini Borutzky,1967 and the stygobitic copepod Speocyclops psezuapsensis Borutzky, 1965 (Turbanov et al. 2016a).