Leucogeorgia mystax, 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 : 63-67

Leucogeorgia mystax sp. nov.

urn:lsid:zoobank.org:act:9AE0998A-E021-4120-B1CA-DC5A021D20D0

Figs 39–41 , 56–57

Diagnosis

This species belongs to the group of Leucogeorgia spp. with modified mouthparts and teeth on the mesomeral claw (vs teeth absent in L. longipes ). Leucogeorgia mystax sp. nov. clearly differs from all congeners by its highly modified mouthparts, viz., two rounded labral lobes with a deep incision in between, and by having a unique gnathochilarium with a distolateral bundle of long setae on the stipites and distal (anterior) rows of long setae on both stipites and lamellae linguales (vs such structures absent in all other congeners).

Etymology

From the Latin ʻ mystax ʼ (= ʻmoustacheʼ), reflecting the presence of long setae laterally on the gnathochilarium, resembling moustaches. Noun in apposition.

Material examined

Holotype

ABKHAZIA – Gagry District • ♂; Gagra Mt Ridge, Arabika karst Massif , Lastochkino Krylo area , Nytshka Cave , depth - 7 m; 43.45° N, 40.31° E; 27 Aug. 2014; I.S. Turbanov leg.; ZMUM.

Paratypes

ABKHAZIA – Gagry District • 1 ♀; same collection data as for holotype; ZMUM • 1 ♀; same collection data as for holotype; IZB .

Description

SIZE AND NUMBER OF BODY RINGS. Holotype male 15 mm long, vertical diameter of largest body ring 1 mm, body with 29 podous rings + 1 apodous ring + telson. Paratype females 15–16 mm long, vertical diameter of largest body ring 1.1–1.2 mm, body with 30 podous rings + 0–1 apodous ring + telson.

COLOUR ( Fig. 39 ). Yellowish white in alcohol.

HEAD ( Figs 39 B–D, 40A–G). Without ommatidia. Frontal setae absent. Labrum without labral teeth, but with two rounded lobes with a deep incision in between; each lobe with ca 7–8 long labral setae. Gnathochilarium (holotype male) with rhomboid promentum; lamellae linguales each with two irregular, transverse, distal rows of 9+11 long setae and one longitudinal row of 4+6 shorter setae; stipites with two irregular, transverse, distal rows of 9–10 long setae and a distolateral bundle of long setae. Antennae long, 1.8 mm long in holotype male, their length 180% of vertical diameter of largest body ring. Lengths of antennomeres I–VIII (in mm): 0.09 (I), 0.39 (II), 0.40 (III), 0.26 (IV), 0.32 (V), 0.23 (VI), 0.07 (VII) and 0.04 (VIII). Length/width ratio of antennomeres I–VII: 0.8 (I), 3 (II), 3.3 (III), 2 (IV), 2.1 (V), 1.6 (VI) and 0.6 (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. 39E ). Ventral side of metazonal area with longitudinal striations. Dorsal side of metazonal area smooth. Metazonal setae abraded from midbody rings. Length of body ring 7 setae ca 6% of vertical diameter of ring.

TELSON ( Fig. 39 F–G). Epiproct with a very short and blunt caudal process, covered with dorsal and lateral setae. Paraprocts rounded, setose, mesal edges slightly bulging. Hypoproct lanceolate, most probably with two apical setae. Setae on telson mainly abraded.

LEGS IN MALES. First pair of legs modified, hook-shaped ( Figs 40 H–I, 41C), with three podomeres; coxa with one seta; prefemur with four setae; femora, postfemora and tibiotarsi coalesced; femur with two setae; postfemur with one seta. Tibiotarsal part with a small distal lobe. Tip slightly tuberculate. Postfemoral and tibial ventral pads developed on pregonopodal legs, then gradually disappearing on postgonopodal legs.

VENTRAL MARGIN OF MALE BODY RING 7 ( Fig. 39H ). Strongly developed, rounded in lateral view.

PENES ( Fig. 41D ). Short, apically with two small subtriangular lobes.

GONOPODS ( Figs 40J , 41 A–B). Promere (p) long and slender, slightly curved anteriad, with a flagellum (f); apical part spatulate, with denticulate margins; basal half with two developed ridges. Mesomere (m) with a robust and denticulate mesomeral claw (mc), mesomeral lamella (ml) with a serrate posterodistal margin, posterior part smooth. Opisthomere (o) bipartite. Anterior branch of o with a solenomere (s), with a medium-sized tip, and a well-developed velum (v), fimbriate at anterior margin. 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 its type locality ( Fig. 57 , red square).

Remarks

This species, with the most bizarre mouthpart modifications, lives in syntopy with L. turbanovi sp. nov., also with modified mouthparts.

Figures

Fig. 39. Leucogeorgia mystax sp. nov., types from Nytshka Cave. A. Paratype ♀, habitus, lateral view (ZMUM). B. Paratype ♀♀, head, lateral view (ZMUM). C. Paratype ♀, head, anterolateral view (IZB). D. Paratype ♀, head, anterior view (IZB). E. Paratype ♀, midbody rings, lateral view (ZMUM). F. Holotype ♂, telson, lateral view (ZMUM). G. Paratype ♀, telson, ventral view (IZB). H. Holotype, body ring 7, lateral view. Scale bars: A = 1 mm; B–H = 0.5 mm.

Fig. 40. Leucogeorgia mystax sp. nov., holotype ♂ from Nytshka Cave (ZMUM). A. Head, dorsal view. B. Head, anterior view. C. Head, anterolateral view. D. Head, ventral view. E. Lamellae linguales, ventral view. F. Left stipe, ventral view. G. Left stipe, lateral view. H. Leg-pair 1, anterior view. I. Left leg 1, lateral view. J. Left gonopods, mesal 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 = 0.2 mm; B–G, J = 0.1 mm; H–I = 0.05 mm.

Fig. 41. Leucogeorgia mystax sp. nov., holotype ♂ from Nytshka Cave (ZMUM). A. Right gonopods, mesal view. B. Right gonopods, lateral view. C. Leg-pair 1, anterior view. D. Penes, posterior view. 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.