Colchiobrachyiulus montanus Vagalinski, 2021

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

Colchiobrachyiulus montanus Vagalinski sp. nov.

Figs 4 , 5

Material examined

(all from Russia, Karachay-Cherkess Republic, Teberda Biosphere Nature Reserve). Holotype: ♂ (ZMUM) (unbroken), Mount Mussa-Achitara in Dombai , 2700-2800 m, alpine meadow, under stones, 29.VII.1986, SIG leg . Paratypes: 1 ♂ (ZMUM) (head to ring 6 and rest of body, gonopods prepared for SEM), 2 ♀♀ (ZMUM) (one unbroken, the other with head to ring 3 and rest of body, left vulva dissected), same collecting data as for holotype ; 1 ♂ (ZMUM) (head to ring 2 (head damaged, gnathochilarium separated), rings 3 to 6, and rest of body (half-broken in the middle, gonopods dissected)), 2 ♀♀ (ZMUM) (one unbroken, the other broken into two pieces), Alibek Canyon near Dombai, 2000-2100 m, sparse Betula stand, litter, under stones, 25.VIII.1986, SIG leg .; 1 ♂ (NMNHS) (head to ring 3, ring 4 to ring 6, pleurotergum 7, and rest of body, penis and gonopods dissected), 1 subad. ♂ (NMNHS) (in 2 pieces), Arkhyz part, VI-VII.1988, A.P. Zolotarev leg.

Diagnosis.

A species of Colchiobrachiulus differing from its single known congener, C. dioscoriadis comb. nov., by its smaller size (males <20 mm in length and 1.3 mm in height, mature females <25 mm in length and 2 mm in height, vs.> 30 mm in length and 2 mm in height for both sexes in C. dioscoriadis comb. nov.), by a shorter epiproct, and by gonopodal details, more specifically by the more narrow apex of the promere and its distomesal process being subequal to the apex, vs. that same process significantly outreaching the apex in C. dioscoriadis comb. nov.; by the apical outgrowth of the opisthomere’s basoposterior process being relatively more narrow, with longer branches at margin; and by the solenomere being uni- rather than bipartite in its distal section.

Name.

Emphasising the high-mountainous occurrence of this species. Adjective.

Description.

Measurements: holotype ♂ in S XI, 43+1+T, L = 16 mm, H = 1.2 mm; paratype ♂♂ in S X, 42-45+1+T, H = 1.15-1.2 mm; paratype ♀♀ in S X-XI, 42-45+1+T, L = 18-22 mm, H = 1.5-1.85 mm.

Colouration (after> 30 years of preservation in alcohol) (Fig. 4 ): Apparently heavily faded, mostly brown; head and collum (Fig. 4B ) with a usual colour pattern; antennae brownish; prozonae dark brown above ozopore level, each with several uneven light spots dorsally, the largest one right above ozopore; metazonae lighter brown-beige; dorsum with a blackish axial line; legs brown; pre-anal ring dark brown, contrasting to the lighter previous ring, paraprocts proximally dark brown, distally lighter.

External structures: Eye patches in adults consisting of 35-40 ommatidia arranged in easily countable vertical rows. Vertigial, supralabral, and labral setae: two, four, and 18-22, respectively. Antennae 1.4-1.5 × as long as head in males and 1.1-1.2 × in females; antennomere 2> 3> 4 ~ 5> 6. Promentum of gnathochilarium separating lamellae linguales in their proximal 2/5 or so, each of the latter with three or four setae in a longitudinal row. Collum mostly smooth, with just two or three shallow grooves at posterolateral corners.

Body rings slightly vaulted. Prozonae with very short and shallow, mostly parallel, longitudinal striae. Metazonae not very deeply, but densely striate, n Schub = 10 or 11; setae apparently mostly abraded, ca. 1/2-2/3 of metazonal length. Ozopores relatively large, placed right in pro-metazonal suture in more anterior body rings, and ca. 1 × their diameter in more posterior ones; sutures not sinuous in front of ozopores. Tarsus of mid-body legs ca. 1.2 × as long as tibia and 3 × as long as apical claw.

Telson (Fig. 4C ): Epiproct moderately long in males, almost reaching the level of the longest paraproctal setae, considerably shorter and stouter in females, ending with a short and blunt hyaline tip turned slightly dorsad. Hypoproct roundly trapezoid, barely protruding behind rear contour of paraprocts in males, broadly rounded in females, completely concealed under paraprocts in females. Paraprocts densely covered with relatively long setae; without distinct rows of shorter setae along caudal margins.

Male sexual characters: Mandibular stipites considerably expanded, protruding mostly ventrad, forming no distinct corner. Leg pair 1 compact, rounded, parallel hooks. Walking legs with crested adhesive pads, both tibial and postfemoral ones gradually reduced posteriad, but still visible until caudalmost pairs. Pleurotergum 7 ventrally forming elongated, narrowly rounded lobes (Fig. 5A ) originating from the zone around pro-metazonal suture, protruding mostly ventro-mesad behind gonopods. Penis (Fig. 5B ) short and stout, with broad and rounded apical lobes ending up in short and blunt terminal lamellae directed distad.

Gonopods (5C, D-H): Promere (Fig. 5D, p in Fig. 5C ) considerably higher than opisthomere, slender, gradually tapering towards a narrowly rounded apex; mesal margin distally bearing a long and fine process with a pointed tip turned mesad; caudal surface with a short and very weakly pronounced median ridge, a broad and shallow median groove, and a deep and narrow distomesal groove, the latter in situ enveloping the lateral side of solenomeral apex, ending up in an even narrower channel running through distomesal process; flagellum thin, slightly longer than height of promere, with a micro-dentate apical part. Opisthomere (Fig. 5C, E-H ) relatively slender; basoposterior process shaped as a broad and flattened lobe running parallel to CBO, mostly fused to it, ending in a multibranched, coral-like, papillose, freely protruding, apical outgrowth; anterior process well-developed, long and tapering, twisted at> 90° around solenomere, partly enveloping the lateral and posterior sides of the latter, both being subequal in height; mesal side with a small lobe (presumably gonocoxal gland), and a rather shallow anteromesal sinus frontal to the gland; two sparse rows of very long, erect, spiniform filaments running along basomedial section of flagellum channel; solenomere very fine and slender, unipartite, sigmoid, without specialised structures apically.

Female sexual characters: Leg pairs 1 (significantly) and 2 (slightly) shorter and thicker than following legs. Vulva (Fig. 5I ) rather elongated, subcylindrical, mostly symmetrical (lateral valve somewhat broader than mesal one), with an obtuse postero-apical margin; operculum as high as bursa; both bursa and operculum apically with rather large hyaline protrusions; setation moderately dense throughout. Receptaculum seminis composed of a relatively narrow and moderately long, digitiform, central tube, and a very thin posterior tube, the latter somewhat bent on its way to a medium-sized, ovoid, posterior ampulla.

General distribution.

NWGC.

Remarks.

Apart from body size and gonopodal structural details, C. montanus sp. nov. differs from C. dioscoriadis comb. nov. also by the shape of the vulval receptaculum (cf. fig. 182 in Vagalinski and Lazányi 2018).

Two of the four paratype females have chunks of tar-like substance attached to the vulvae, like those observed in C. dioscoriadis comb. nov.

Figures

Figure 4. Colchiobrachyiulus montanus sp. nov., ♂ holotype A habitus B head and body rings 1 - 3 C telson, lateral views. Not to scale.

Figure 5. Colchiobrachyiulus montanus sp. nov., paratypes (ZMUM) A-C ♂ from near Arkhyz, Russia A left flange of pleurotergum 7, ventro-lateral view B penis, caudal view C right gonopods, oral view D-H ♂ from Mount Mussa-Achitara, Russia D right promere, caudal view E distal part of left opisthomere, mesal-oral view F right opisthomere, caudal view G apical part of left opisthomere, with the flagellum remained in its channel, oral view H branches of apical outgrowth of basoposterior process I ♀ from Mount Mussa-Achitara, Russia left vulva, caudal view. Scale bars: 0.2 mm (A-C, I), 0.1 mm (D, F), 0.05 mm (E, G), 0.01 mm (H). Abbreviations: ap anterior process, ao apical outgrowth, bpp basoposterior process, ct central tube, dmg distomesal groove, dmp distomesal process, f flagellum, fc flagellum channel, hp hyaline protrusions, mg median groove, mr median ridge, p promere, pa posterior ampulla, pt posterior tube, s solenomere, sf spiniform filaments.