Omobrachyiulus lazanyiae 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 lazanyiae Vagalinski sp. nov.

Figs 28 , 29 , 30

Material examined

(SMNG). Holotype: ♂ (in two pieces, gonopods, leg 6 and a mid-body leg dissected), Georgia, AR Abkhazia, Gulripsh Distr., 6 km E of Tsebelda, right bank of Jampali River, Cave Nizhnyaya Shakuranskaya , 8-9.XI.1987, N. Myuge leg. Paratype: 1 ♂ (in head, collum, rings 2-3, ring 4, rings 7-8, and rest of body; leg pair 1, leg 7, a mid-body leg, right flange of ring 7, and hypoproct dissected; opisthomeres and one promere prepared for SEM), same collecting data as for holotype .

Diagnosis.

A species of Omobrachyiulus most similar to O. implicitus and O. fasciatus sp. nov. by the overall shape of the promere, the weakly developed basoposterior process and mesomeroidal lobe of the opisthomere, and the broad, collar- or scarf-shaped, apical outgrowth of the basoposterior process, having a characteristic, wrinkled, lamellar part, partially covering the mesal side of the solenomere. Differs from those two species mainly by the solenomere which is apically slender (not clavate as in O. fasciatus sp. nov.), divided in two parallel, tightly contiguous (not strongly diverging as in O. implicitus ) branches, subapically on mesal side bearing a minute lobe with several denticles, protruding perpendicular to the main axis of the solenomere.

Name.

Honours the friend and long-term collaborator of the first author, Eszter Lazányi, a diplopodologist from the Hungarian Natural History Museum, Budapest, Hungary, whose scientific contributions mostly focus on the tribe Brachyiulini as well.

Description.

Measurements: holotype ♂ in S IX, 41+2+T, L = 12 mm, H = 0.95 mm; paratype ♂ in S IX, 42+1+T, L = 12.5 mm, H = 0.9 mm.

Colouration (strongly faded from the ethanol conservation) (Fig. 28A ): mostly brownish beige; head and collum with the usual pattern; prozonae dorsally with two dark transverse stripes, one in frontal section and the other next to pro-metazonal suture, the former broader; a dark washed spot in front of ozopores; metazonae uniformly light brown-beige; dorsum with a blackish axial line.

External structures: Eye patches in adults consisting of 20-30 ommatidia arranged in unclear vertical rows. Vertigial, supralabral, and labral setae: two, four (one ♂ with five), and 16, respectively. Antennae (in Fig. 28A ) 1.1-1.2 × as long as head in males; antennomere 2> 3 ≥ 4 = 5. Gnathochilarium with a very small promentum separating both lamellae linguales over ca. 1/4 of their length, each latter with four setae in a longitudinal row. Collum completely smooth, with just one or two faint longitudinal grooves near posterolateral corners.

Body rings not vaulted. Prozonae with very short, shallow, scattered, longitudinal striae in posterior parts. Metazonae moderately deeply striated, n Schub = 7 or 8; metazonal setae from 1/2 (in frontal and mid-body rings) to 2/3 (in caudalmost rings) of metazonal length. Ozopores set tightly behind pro-metazonal suture in more anterior rings, moved slightly backwards, to ca. half their diameter behind the suture in more posterior rings, sutures being gently sinuous in front of ozopores. Tarsus of mid-body legs ca. 1.3 × as long as tibia and ca. 3 × as long as apical claw.

Telson (Fig. 28B ): Epiproct rather long (approximately reaching the level of longest paraproctal setae), straight, ending bluntly without distinct hyaline tip; bearing several long setae. Hypoproct (Fig. 29A ) rounded subtrapezoidal, ventrally with two distal paramedian setae; slightly protruding past caudal margin of paraprocts. Paraprocts sparsely setose.

Male sexual characters: Mandibular stipites (in Fig. 28A ) rather weakly expanded, forming a narrowly rounded anterior corner. Leg pair 1 (Fig. 29B ) markedly slender, slightly converging hooks with minute pointed tarsal remnants in the paratype (black arrow), the latter being absent in the holotype. Leg pair 2 somewhat shorter than following pairs. Adhesive pads as in O. fasciatus sp. nov. Ventral protrusions of pleurotergum 7 (Fig. 29C ) similar to those in O. fasciatus sp. nov., but insignificantly widening distally.

Gonopods (Figs 29D , 30 ): Promere (Fig. 30A ) rather stout, subequal to opisthomere, broadest at base, insignificantly tapering towards a broadly rounded apex; caudal surface with a pronounced median ridge, a deep and broad median groove, a small, but deep distal groove near lateral margin, and a rather weakly pronounced distolateral lobe. Opisthomere (Figs 29D , 30B-E ) relatively slender; basoposterior process similar to that in O. fasciatus sp. nov., but with a broader apical outgrowth surrounding the proximal part of solenomere from all sides except frontally, and having a less strongly developed lamellar part; a (presumably) anterior process present as a small slender leaf running tightly contiguous with the basal part of solenomere; mesomeroidal lobe moderately pronounced, without an apicolateral part; mesal side mostly as in O. fasciatus sp. nov., but with somewhat shorter spiniform filaments at flagellum channel; basal section of seminal channel densely micro-spiculate; solenomere slender, gently sigmoid, directed distad; apex divided into two parallel, tightly contiguous branches, the mesal one bearing a minute lobe protruding meso-caudad, with several denticles at margin.

Female sexual characters: unknown.

General distribution.

SWGC.

The Opisthomere roseni group

Characterisation. Both gonopod pairs subequal in height. Promere showing a distinct, deep, distal groove. Opisthomere more or less robust and compact, with a strongly pronounced mesomeroidal lobe, a basoposterior process with a moderately pronounced proximal part in the shape of a lamellar ridge or lobe, ending with an apical outgrowth with a shield-like median part and a more or less pronounced lamellar mesal part turned anteriad, a well-differentiated, freely protruding anterior process of various size and shape, a moderately to very deep anteromesal sinus, a flagellum channel overgrown with rather long and erect spiniform filaments, and a stout, tubular, unipartite solenomere, this being broadened apically and turned more or less anteriad. Vulva with operculum subequal in height to bursa.

Included species.

O. roseni (Verhoeff, 1921)

O. faxifer Vagalinski, sp. nov.

O. zuevi Vagalinski, sp. nov.

Figures

Figure 28. Omobrachyiulus lazanyiae sp. nov., ♂ holotype A head and body rings 1 - 3, lateral, slightly dorsal view B telson, lateral view. Not to scale.

Figure 29. Omobrachyiulus lazanyiae sp. nov., ♂ paratype (SMNG) A hypoproct (basal corners broken off), ventral view B right leg 1, mesal view C right flange of pleurotergum 7, ventro-lateral view D right opisthomere, mesal, somewhat oral view. Scale bars: 0.2 mm (D), 0.1 mm (A-C). Abbreviations: ao apical outgrowth of basoposterior process, aol lamellar part of basoposterior process' apical outgrowth, fc flagellum channel, g (supposed) gonocoxal gland, ml mesomeroidal lobe, s solenomere, sc seminal channel, sf spiniform filaments, sl mesal lobe of solenomere.

Figure 30. Omobrachyiulus lazanyiae sp. nov., gonopods of ♂ paratype (SMNG) A right promere (flagellum broken off), caudal view B right opisthomere, mesal view C left opisthomere, latero-oral view D apical part of right opisthomere, mesal view E distal part of left opisthomere, latero-oral view. Scale bars: 0.1 mm (A-C), 0.05 mm (E), 0.02 mm (D). Abbreviations: ao apical outgrowth of basoposterior process, aol lamellar part of basoposterior process' apical outgrowth, bpp basoposterior process, dg distal groove, fc flagellum channel, g (supposed) gonocoxal gland, mg median groove, ml mesomeroidal lobe, mr median ridge, s solenomere, sc seminal channel, sf spiniform filaments, si anteromesal sinus, sl mesal lobe of solenomere.