Leucogeorgia rediviva Golovatch, 1983

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 : 20-25

Leucogeorgia rediviva Golovatch, 1983

Figs 11–13 , 56–57

Leucogeorgia rediviva Golovatch, 1983: 48 .

Diagnosis

This species belongs to the group of Leucogeorgia spp. with modified mouthparts and with teeth on the mesomeral claw (vs absence of teeth in L. longipes ). Leucogeorgia rediviva differs from L. mystax sp. nov., L. profunda sp. nov. and L. turbanovi sp. nov. by having a mesomeral claw that does not directly continue with the margin of the lamella, but is with a clear connection to the mesal side (vs a mesomeral claw that continues directly with the margin of the lamella, both parts being fully coalesced in L. mystax sp. nov., L. profunda sp. nov. and L. turbanovi sp. nov.). Leucogeorgia rediviva differs from L. caudata sp. nov. by having a more slender mesomeral claw and by the absence of a very long and sharp process on the epiproct, with a hyaline tip (vs a more robust mesomeral claw and the presence of a long and sharp process with a hyaline tip in L. caudata sp. nov.). Leucogeorgia rediviva differs from the superficially most similar L. redivivoides sp. nov. by having a somewhat more smooth and high central part of the mesomeral lamella, in the form of a lobe (vs the mesomeral lamella flattened, slightly denticulate in the central part in L. redivivoides sp. nov.), a lanceolate hypoproct (vs a subrhomboid hypoproct in L. redivivoides sp. nov.), a well-developed, rounded, ventral margin of male body ring 7 (vs ventral margin of male body ring 7 low, more squarish, with a right posterior angle in L. redivivoides sp. nov.) and a somewhat more elongate body with 38–47 podous rings in males (vs body more stocky, with 28–35 podous rings in males of L. redivivoides sp. nov.).

Material examined

ABKHAZIA – Gudauty District • 1 ♂; Gumishkhinsky karst Massif, Novyi Afon, Novoafonskaya (= New Athos) Cave , hall Apsny ; 43.09° N, 40.81° E; 20 May 2016; S.A. Kapralov leg.; ZMUM • 1 ♂; Gumishkhinsky karst Massif, Gumishkha Mountain , near Khabyu village, Khabyu Cave ; 43.20°N, 40.79°E;1990; V.Kiselev leg.; SMNG • 2♂♂; Bzyb Mt Ridge , Khipstinsky karst Massif, Khipsta Mountain , Snezhnaya Cave , depth - 780 m; 43.26° N, 40.72° E; 21 Feb. 1983; E. Laionas leg.; ZMUM • 1 ♂; same locality as for preceding; 7 Jun. 1985; A. Kritsky leg.; ZMUM • 1 ♂; same locality as for preceding; 5 Feb. 2015; S. Kebez and O. Lebedeva leg.; IZB • 1 ♂; same locality as for preceding, depth - 1300 m, between Iks and Penelopa halls; 13 Aug. 2017; A.S. Tyagunova leg.; ZMUM • 1 ♂; same locality as for preceding, depth - 1330 m, Tronnyi Hall; 15 Aug. 2017; A.S. Tyagunova leg.; ZMUM .

Redescription

SIZE AND NUMBER OF BODY RINGS. Males 26–35 mm long, vertical diameter of largest body ring 2–2.3 mm, body with 38–47 podous rings + 0–2 apodous rings + telson. Male from Novoafonskaya Cave 33 mm long, vertical diameter of largest body ring 2.1 mm, body with 40 podous rings + 0 apodous ring + telson.

COLOUR ( Fig. 11 ). In alcohol from pale yellow to dark brown.

HEAD ( Figs 11 B–C, 12C, E). Without ommatidia. Frontal setae absent. Labrum either without labral teeth or with three very small, reduced labral teeth; 3+2–3+3 supralabral and 30–32 labral setae. Male from Novoafonskaya Cave with three small labral teeth; with 3+3 supralabral and 30 labral setae. Gnathochilarium with a triangular promentum; lamellae linguales with 1+1 long distal setae and 3+4 long proximal setae in male from Khabyu Cave; stipites with 3+3 long distolateral setae; no other setae. Antennae 3.8 mm long (in male from Novoafonskaya Cave), their length ca 180% of vertical diameter of largest body ring. Lengths of antennomeres I–VIII (in mm): 0.19 (I), 0.76 (II), 0.86 (III), 0.73 (IV), 0.68 (V), 0.37 (VI), 0.16 (VII) and 0.05 (VIII). Length/width ratio of antennomeres I–VII: 0.8 (I), 3.4 (II), 3.7 (III), 3 (IV), 2.8 (V), 1.5 (VI) and 0.9 (VII). Lengths of antennae in other males 180–190% of vertical diameter of largest body rings. 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. 11F ). Ventral and ventrolateral sides of metazonal area with longitudinal striations. Dorsal side with poorly visible striations. Length of midbody setae ca 6% of vertical diameter of rings.

TELSON ( Fig. 11E , G–H). Epiproct variable, with a short to somewhat longer, blunt or somewhat acuminate preanal process. Paraprocts rounded, setose. Hypoproct lanceolate, with seven long setae in male from Novoafonskaya Cave.

LEGS IN MALES. First pair of legs modified, hook-shaped ( Fig. 12 A–B), with three complete podomeres; coxa with one seta; prefemur with 5–6 setae; femur, postfemur and tibiotarsus coalesced; femur with 3–5 setae; postfemur with one seta; tibiotarsus with a small distal lobe (tarsal remnant). Tip tuberculated. Postfemoral and tibial ventral pads poorly developed on pregonopodal legs, then gradually disappearing on postgonopodal legs.

VENTRAL MARGIN OF BODY RING 7 ( Fig. 11D ). Well-developed, rounded in lateral view.

PENES ( Fig. 12F ). Elongate, with two subtriangular apical lobes.

GONOPODS ( Figs 12D , 13 ). Promere (p) long and slender, with a flagellum (f); apical part spatulate, with denticulate margins; basal half with two developed ridges. Mesomere (m) with a well-developed denticulate mesomeral claw (mc); mesomeral lamella (ml) high, convex in central part, distal margin smooth, posterior part finely fimbriate. Opisthomere (o) bipartite.Anterior branch of o with a solenomere (s) with a medium-sized tip, 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).

Type locality

Verkhne-Esherskaya Cave (= Sobachya = Dzaglis), 43.08° N, 40.91° E, near Verkhnyaya Eshera village, Sukhum District, Abkhazia.

Distribution

Known only from four caves in the Gudauty and Sukhum districts in Abkhazia ( Fig. 57 , violet square).

Remarks

Given that the holotype of L. rediviva appears to have been lost (S. Golovatch pers. comm.), while the female paratype is still available in the ZMUM collection, our identification of this species is based solely on the original description of Golovatch (1983). We have assigned to L. rediviva only males from three caves, viz., Snezhnaya, Novoafonskaya and Khabyu, of which the Novoafonskaya Cave is the closest (just a few kilometers away) to the type locality. The characters of the males from these caves generally coincide with Golovatch’s (1983) description, albeit with some small exceptions. Both males from Novoafonskaya and Khabyu caves are characterized by the presence of three small, reduced labral teeth, while L. rediviva was characterized by Golovatch (1983) by the absence of labral teeth, a character shared with other congeners with modified mouthparts. Modified mouthparts, including the absence of labral teeth, are well-known not only in Leucogeorgia , but also in some species of Typhloiulus Latzel, 1884 and Trogloiulus Manfredi, 1931 . Recently, one of us (DA) examined specimens of Typhloiulus with modified mouthparts from a cave in Italy, where intrapopulation variability was observed in the structure of the labrum, which may be toothless or with three teeth developed to varying degrees, but never developed as in the congeners with normal mouthparts. Thus, we do not consider the presence of three reduced labral teeth in some specimens to be an important feature. Males from the Snezhnaya Cave possess a somewhat longer and more robust process on the epiproct (see Fig. 11 G–H). Yet, this process can be variable in some species as well, even within the same population (see below and Antić et al. 2018b: 261, fig. 1e–g), and in this case we do not allot it too much importance either.

The Novoafonskaya Cave is the type locality of L. caudata sp. nov., also with modified mouthparts, where the two species are living at least sympatrically. The presence of two species of Leucogeorgia with modified mouthparts in the same cave is not rare, since there are a few more examples where two species are sympatric or even syntopic in the same cave (see below).

In the Snezhnaya Cave, several specimens were observed underwater. Some of them were almost motionless and seemed to ‘graze’ the sediment, while others were poorly mobile and attached to the bottom, despite a strong water current (I. Turbanov pers. comm.).

Figures

Fig. 11. Leucogeorgia rediviva Golovatch, 1983 (A–G: ♂ from Novoafonskaya Cave (ZMUM); H: ♂ from Snezhnaya Cave (ZMUM)). A. Habitus, lateral view. B. Head, lateral view. C. Head, anterior view. D. Body ring 7, lateral view. E. Telson, posterior view. F. Midbody rings, lateral view. G. Telson, lateral view. H. Telson, lateral view. Arrows indicate three reduced labral teeth on C, or metazonal setae on F. Scale bars: 1 mm.

Fig. 12. Leucogeorgia rediviva Golovatch, 1983, ♂ from Khabyu Cave (SMNG). A. Leg-pair 1, anterior view. B. Left leg 1, lateral view. C. Head, ventral view. D. Left gonopods, mesal view. E. Detail of labrum, ventral view. F. Penes, posterior 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 bars: A–B, D–E = 0.1 mm; C, F = 0.2 mm.

Fig. 13. Leucogeorgia rediviva Golovatch, 1983, gonopods. A. ♂ from Khabyu Cave, right gonopods, mesal view (SMNG). B. ♂ from Novoafonskaya Cave, left gonopods, lateral view (ZMUM). C. ♂ from Novoafonskaya Cave, right gonopods, mesal view (ZMUM). D. ♂ from Snezhnaya Cave, left gonopods, lateral view (ZMUM). E. ♂ from Snezhnaya Cave, right gonopods, mesal view (ZMUM). Scale bars: 0.3 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.