Leucogeorgia oculata, Antić & Reip, 2020

Antić, Dragan Ž. & Reip, Hans S., 2020, The millipede genus Leucogeorgia Verhoeff, 1930 in the Caucasus, with descriptions of eleven new species, erection of a new monotypic genus and notes on the tribe Leucogeorgiini (Diplopoda: Julida: Julidae), European Journal of Taxonomy 713, pp. 1-106 : 47-52

Leucogeorgia oculata sp. nov.

urn:lsid:zoobank.org:act:4F63C54D-B233-4BE1-A448-E2BAA27764F5

Figs 29–31 , 56–57

Archileucogeorgia sp. – Ghilarov 1972: 38.

Diagnosis

This species belongs to the group of Leucogeorgia spp. without modified mouthparts, but it clearly differs from all other congeners by the pigmented body, the presence of ommatidia and the absence of metazonal setae (vs absence of both pigmentation and ommatidia and the presence of metazonal setae in all other congeners).

Etymology

From the Latin ʻ oculatus ʼ (= ʻhaving eyesʼ), reflecting the presence of ommatidia. Adjective.

Material examined

Holotype

RUSSIA – Adygea, Caucasian Biosphere Nature Reserve • ♂; Lagonaki Plateau, Lunnaya glade , in soil 0–15 cm; 43.94° N, 39.88° E; 8 Sep. 2012; Y. Chumachenko leg.; ZMUM.

Paratypes

RUSSIA – Adygea, Caucasian Biosphere Nature Reserve • 3 ♂♂, 4 ♀♀, 1 juv.; same collection data as for holotype; ZMUM .

Other material

RUSSIA – Adygea, Caucasian Biosphere Nature Reserve • 4 ♂♂; Lagonaki Plateau ; 44.03° N, 39.96° E; 2015; Y. Chumachenko leg.; ZMUM • 30 ♂♂, 7, ♀♀, 4 juvs; Lagonaki Plateau, Instruktorskaya cleft , subalpine meadow, in soil 0–10 cm deep; 11 Sep. 2013; Y. Chumachenko; ZMUM • 5 ♂♂, 5 ♀♀; same collection data as for preceding; IZB • 5 ♂♂, 5 ♀♀; same collection data as for preceding; SMNG • 1 ♂, 4 ♀♀, 3 juvs; Pasture Abago , litter; 43.93° N, 40.23° E; 1800 m a.s.l.; 6 Jun. 2009; Y. Chumachenko leg.; ZMUM .

Description

SIZE AND NUMBER OF BODY RINGS. Holotype male 9 mm long, vertical diameter of largest body ring 0.8 mm, body with 35 podous rings + 3 apodous rings + telson. Paratype males 7–10 mm long, vertical diameter of largest body ring 0.7–0.8 mm, body with 28–37 podous rings + 2–5 apodous rings + telson. Paratype females 8–11.5 mm long, vertical diameter of largest body ring 0.8–1 mm, body with 32–39 podous rings + 2–4 apodous rings + telson. Largest male 11 mm long, vertical diameter of largest body ring 0.8 mm, body with 38 podous rings + 2 apodous rings + telson. Largest female 13 mm long, vertical diameter of largest body ring 1.1 mm, body with 44 podous rings + 2 apodous rings + telson.

COLOUR ( Figs 29–30 ). Variable, from pale yellowish to dark grey.

HEAD ( Fig. 29 B–C). Males and females with 8–12 and 8–13 ommatidia per roundish eye field, respectively. Labrum with three teeth, four supralabral setae and 16 labral setae (paratype male). Gnathochilarium (paratype male) with rhomboid promentum; lamellae linguales with 3+3 setae in one row, stipites with 3+3 long distolateral setae and 4+5 short medial setae each. Antennae short, 0.7 mm long in holotype male, their length ca 90% of vertical diameter of largest body ring. Lengths of antennomeres I–VIII (in mm): 0.06 (I), 0.15 (II), 0.13 (III), 0.11 (IV), 0.12 (V), 0.08 (VI), 0.03 (VII) and 0.02 (VIII). Length/width ratio of antennomeres I–VII: 0.8 (I), 2 (II), 1.6 (III), 1.4 (IV), 1.2 (V), 0.9 (VI) and 0.5 (VII). Antennomeres V and VI each with a terminal corolla of large sensilla basiconica bacilliformia; antennomere VII with a terminal corolla of small sensilla basiconica bacilliformia.

BODY RINGS ( Fig. 29E ). Entire metazonal area with longitudinal striations. Metazonal setae absent.

TELSON ( Fig. 29 F–G). Epiproct variable in length, from short to long, blunt, sloping slightly downwards and covered with dorsal and lateral setae. Paraprocts rounded, with 3+3 setae. Hypoproct without any modifications.

LEGS IN MALES. First pair of legs modified, hook-shaped ( Fig. 31 D–E), with three podomeres; coxae each with one seta; prefemora each with 4–5 setae; femora, postfemora and tibiotarsi coalesced; femur with two setae; postfemur with one seta. Tibiotarsal part with a small distal lobe (tarsal remnant). Tip slightly tuberculated. Postfemoral and tibial ventral pads poorly developed on anterior legs, then gradually disappearing towards posterior legs.

VENTRAL MARGIN OF MALE BODY RING 7 ( Fig. 29D ). Poorly developed, low.

PENES ( Fig. 31C ). Short, apically with two small subtriangular lobes.

GONOPODS ( Fig. 31 A–B). Promere (p) long and slender, with a flagellum (f); apical part spatulate, with poorly denticulated margins. Mesomere (m) with a robust and denticulate mesomeral claw (mc); mesomeral lamella (ml) with a smooth and slightly concave distal margin and a posterior rise, posterior part finely fimbriate. Opisthomere (o) bipartite. Anterior branch of o with a solenomere (s) with a long tip significantly exceeding posterior part of lamella, and a well-developed and fimbriate velum (v). Posterior branch of o in form of a shield-like protective lamella (pl). Mesomere and opisthomere connected basally with an accessory membrane (am).

Distribution

Known only from Lagonaki Plateau and Pasture Abago, Caucasian Biosphere Nature Reserve, Russia ( Fig. 57 , red triangles).

Remarks

This is probably an endogean subalpine species. It is the only member of the genus characterized by the presence of both a pigmented body and ommatidia, and the absence of metazonal setae. Ghilarov (1972) recorded this species as “ Archileucogeorgia sp.” (det. J. Gulička) from Pasture Abago as well.

Figures

Fig. 29. Leucogeorgia oculata sp. nov., from Lagonaki Plateau (ZMUM). A. Holotype ♂, habitus, lateral view. B. Holotype, anterior part of body, lateral view. C. Paratype ♀, head, anterior view. D. Non-type ♂, body ring 7, lateral view. E. Holotype, midbody rings, lateral view. F. Holotype, telson, lateral view. G. Non-type ♂, telson, lateral view. Scale bars: A, E = 1 mm; B–D, F = 0.5 mm.

Fig. 30. Leucogeorgia oculata sp. nov., specimens from Lagonaki Plateau, habitus, lateral views. A. Largest paratype ♀ (ZMUM). B. Smallest paratype ♀ (ZMUM). C–F. Non-type ♂♂ (IZB). Scale bars: 1 mm.

Fig. 31. Leucogeorgia oculata sp. nov., paratype ♂ from Lagonaki Plateau (ZMUM). A. Left gonopods, lateral view. B. Left gonopods, mesal view. C. Penes, posterior view. D. Leg-pair 1, anterior view. E. Left leg 1, lateral view. Abbreviations: am = accessory membrane; f = flagellum; m = mesomere; mc = mesomeral claw; ml = mesomeral lamella; o = opisthomere; p = promere; pl = protective lamella; s = solenomere; v = velum. Scale bar: 0.2 mm.

Fig. 56. General distribution of the Caucasian leucogeorgiinines. The white dashed line hypothetically indicates the boundary between the northwestern and southeastern groups of species of the genus Leucogeorgia Verhoeff, 1930.

Fig. 57. Distribution of the northwestern group of the genus Leucogeorgia Verhoeff, 1930.