Omobrachyiulus armatus Vagalinski, 2021

Vagalinski, Boyan & Golovatch, Sergei I., 2021, The millipede tribe Brachyiulini in the Caucasus (Diplopoda, Julida, Julidae), ZooKeys 1058, pp. 1-127 : 1

Omobrachyiulus armatus Vagalinski sp. nov.

Figs 18 , 19 , 20

Material examined

(all from Georgia). Holotype: ♂ (unbroken) (ZMUM), Manglisi , Quercus forest, 12.XI.1984, E. Kvavadze leg. Paratypes: 2 ♂♂ (ZMUM) (one in head to ring 2, ring 3 to ring 6, pleurotergum 7, and rest of body; right antenna, leg pair 2, penis, legs 6, 7, and mid-body leg dissected, opisthomeres and left promere prepared for SEM; the other unbroken with removed hypoproct), 3 ♀♀ (ZMUM), same collecting data as for holotype ; 1 ♂ (ZMUM) (partly broken in anterior section), 2 ♀♀ (ZMUM) (one unbroken, the other in 3 pieces), AR Ajara, E of Khulo , decidous forest near spring, rock, litter, 10.X.1981 , SIG leg.; 2 ♂♂ (ZMUM) (one in three pieces, with dissected gonopods, the other with a missing posterior body half), 1 ♂ (NHMD) (unbroken), 1 ♂ (NMNHS) (in two pieces), 1 ♀ (NMNHS) (unbroken), Kutaisi District, Sataplia Nature Reserve , forest litter and under stones, 25.X.1981 , SIG leg.; 1 ♂ (ZMUM) (in three pieces, with dissected gonopods), 1 ♂ (IBER) (unbroken), 5 ♀♀ (ZMUM) (unbroken), 7 juv. (ZMUM) (two unbroken, the rest in 2 or more fragments), AR Ajara, Khulo , 900 m, forest of Quercus , Abies , Alnus , litter, 11.X.1981 , SIG leg.; 2 ♂♂, 3 ♀♀ (SMNG), Georgia , Samtskhe-Javakheti, 17.IX.2011 , Bakuriani, Tskhratskaro Pass , 41.7067°N, 43.5058°E, 2080 m a.s.l., 17.IX.2011, F. Walther leg.

Diagnosis.

A species of Omobrachyiulus most similar to O. hortensis by the promere significantly outreaching the opisthomere, the latter possessing a massive lobe-like basoposterior process forming two distinct corners, a basal and a distal one, and having a micro-spiculate mesal side, and a unipartite solenomere with a slender rod-like ending. Differs from O. hortensis mainly by the broad, unipartite, collar-shaped, apical outgrowth of the basoposterior process dentate at margin, that same outgrowth being clearly tripartite in the latter species, consisting of a mesal lamellar, a median fan-like, and a lateral spiniform part.

Name.

Meaning armed in Latin, referring to the overall appearance of the male including the opisthomere bearing various spines and denticles, the large tapering mandibular stipites, and the prominent dentate hypoproct. Adjective.

Description.

Measurements: holotype ♂ in S IX, 45+1+T, L = 17 mm, H = 1.4 mm; paratype ♂♂ in S IX, 44-46+1+T, L = 16-20 mm, H = 1.35-1.55 mm; paratype ♀♀ in S IX, 44-46+1+T, L = 17.5-22 mm, H = 1.7-1.9 mm.

Colouration (most specimens considerably faded in ethanol) (Fig. 18 ): Head light brown with the usual dark band between eye patches, distal part of male mandibular stipites saturated dark brown, contrasting to the much lighter proximal part; body mostly light brown, lighter ventrally; prozonae dorsally with dark grey to blackish transverse stripes; each metazona with a blurred dark brown band encircling entire ring; dorsum with a black axial line.

External structures: Eye patches in adults consisting of 30-35 ommatidia, usually arranged in easily countable vertical rows. Vertigial, supralabral, and labral setae: two, four, and 19-23, respectively. Antennae (in Fig. 18B ) ca. 1.6-1.7 × as long as head in males and 1.1-1.4 × in females; antennomere 2> 3 = 4 = 5> 6. Gnathochilarium with an elongated promentum, the latter separating both lamellae linguales> halfway; four setae in a longitudinal row on each lamella. Collum completely smooth.

Body rings barely vaulted. Prozonae with short and very shallow longitudinal striae spread across whole surface. Metazonae moderately deeply striated, n Schub = 7 or 8 in males and 9 or 10 in females; metazonal setae rather sparse, 2/3 (in middle to caudal parts of body)-3/4 (in frontal part of body) of metazonal length. Ozopores set tightly behind pro-metazonal suture in more anterior rings, gradually moved further backwards, to nearly equal to their diameter behind the suture in caudalmost rings; sutures straight to gently sinuous in front of ozopores. Tarsus of a mid-body leg slightly shorter than to equal to tibia, and nearly 3 × as long as apical claw.

Telson (Fig. 18C ): Epiproct moderately long, stout, shorter than, or barely reaching, the level of longest paraproctal setae, ending bluntly, without a distinct, or with a poorly defined, hyaline tip; with several long setae dorsolaterally. Hypoproct (Fig. 19A ) in males very broad, subrectangular, its margin with three large median teeth and two lower protuberances laterally on each side, the latter being sometimes serrate; in females broadly rounded, tightly adhering under paraprocts; ventral surface sparsely setose. Paraprocts moderately densely setose, without distinct row of shorter setae along caudal margins.

Male sexual characters: Mandibular stipites (in Fig. 18B ) strongly expanded, forming an acute anterior corner. Leg pair 1 compact rounded hooks, slightly turned against one another. Leg pair 2 and sometimes 3 slightly thicker than following pairs, adhesive pads rather weakly developed, becoming better developed towards mid-body, postfemoral ones disappearing in caudal third of body, tibial ones present until last leg pairs; femora from leg pair 5 to mid-body legs distally with a small shallow pit (arrow in Fig. 19B ). Pleurotergum 7 considerably enlarged, ventrally forming large and rounded lobes (Fig. 19C ) originating mostly from metazona, protruding caudoventrad behind gonopods. Penis (Fig. 19D ) very short, slightly broader than long, compressed anterocaudally, with very short apical lobes ending in rounded terminal lamellae directed distad.

Gonopods (Figs 19E, F , 20 ): In situ considerably protruding from gonopodal sinus. Promere (Fig. 20B, p in 20A) considerably higher than opisthomere, slender; mesal margin mostly straight, lateral margin parallel to mesal one in proximal section, distally steeply slanting towards a blunt apex; caudal surface with a short, well-pronounced, median ridge, and a broad and rather shallow median groove; with a distinct, deep, distal groove, and a smooth, rounded, distomesal lobe directed caudad; flagellum slightly longer than height of promere. Opisthomere (Figs 19E, F , 20A, C-E ) compact and robust; basoposterior process represented by a massive lobe with a micro-spiculate mesal surface, distally forming a very broad apical outgrowth bent anteriad, tightly adhering to caudal and partly to mesal side of solenomere, with several teeth/horns at margin; anterior process shaped as a lamellar ridge with a slightly serrate anterior margin; mesomeroidal lobe broad and rounded, moderately developed; a rounded hump-like lobe on lateral side; mesal side with a large lobe (presumably gonocoxal gland) leading to the seminal channel, and a large anteromesal sinus frontally to the gland; solenomere unipartite, mostly straight, relatively broad, apically with a fine digitiform process; a group of very long, erect, spiniform filaments in proximal section of flagellum channel.

Female sexual characters: Leg pairs 1 and 2 shorter, leg pair 2 also thicker, than following legs. Vulva (Fig. 19G ) mostly symmetrical (lateral valve somewhat more oblique than mesal one), rather elongate, slightly compressed on sides; bursa with an obtuse postero-apical margin; operculum shorter than bursa, both ending up with well-developed hyaline protrusions; setation denser on bursa than on operculum. Receptaculum seminis consisting of a long and mostly straight central tube with a somewhat enlarged bottom part, and a long and thin posterior tube forming several spiral twists on its way to an ovoid posterior ampulla.

General distribution.

LECA-COLC.

Figures

Figure 18. Omobrachyiulus armatus sp. nov., ♂ holotype A habitus B head and body-rings 1 - 3 C telson, lateral views. Not to scale.

Figure 19. Omobrachyiulus armatus sp. nov., ♂ (A-F) and ♀ (G) paratypes from near Khulo, AR Ajara, Georgia (ZMUM) A hypoproct, ventral view B leg 6 (coxa not shown) C right flange of pleurotergum 7, ventro-lateral view D penis, caudal view E right opisthomere, caudo-mesal view F same, latero-oral view G left vulva, caudal, slightly mesal view. Scale bars: 0.2 mm (C, G), 0.1 mm (A, B, E, F) 0.6 mm (D). Abbreviations: ao apical outgrowth of basoposterior process, ap anterior process, bpp basoposterior process, ct central tube, ml mesomeroidal lobe, pa posterior ampulla, pt posterior tube, s solenomere, sf spiniform filaments.

Figure 20. Omobrachyiulus armatus sp. nov., gonopods of ♂ paratype from near Manglisi, Georgia (ZMUM) A left gonopods, mesal view B left promere, caudal view C right opisthomere, mesal view D left opisthomere, lateral view E distal part of right opisthomere, mesal view. Scale bars: 0.1 mm. Abbreviations: ao apical outgrowth of basoposterior process, ap anterior process, bpp basoposterior process, dg distal groove, f flagellum, fc flagellum channel, g (supposed) gonocoxal gland, lp lateral lobe, mg median groove, ml mesomeroidal lobe, mr median ridge, s solenomere, sc seminal channel, sf spiniform filaments, si anteromesal sinus.