Iraniulus tricornis Vagalinski, 2021

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

Iraniulus tricornis Vagalinski sp. nov.

Figs 9 , 10 , 11

Material examined

(all from Georgia, Svanetia): Holotype: ♂ (unbroken) (ZMUM), Khumpreri River (left affluent of Enguri), near Dizi, 1.5-2 km before the influx, ca. 1000 m a.s.l., leaf litter, 14.IX.1986, A. Ryvkin leg. Paratypes: 6 ♂♂ (ZMUM) (one in 4 pieces, gonopods prepared for SEM, leg pair 2 and penis dissected; another in head and 2 pieces, gonopods in situ, the rest unbroken), 1 ♂ (NMNHS) (in 2 pieces with dissected gonopods), 1 ♂ (NHMD) (unbroken), 1 ♂ (IBER) (in 2 pieces, gonopods dissected, one flagellum prepared for SEM), 3 ♀♀ (ZMUM) (unbroken), 1 ♀ (NMNHS) 1 ♀ (NHMD), 1 ♀ (IBER) (all unbroken), 2 juv. (unbroken), same collecting data as for holotype ; 3 ♂♂ (one in head to ring 3, ring 4-6, pleurotergum 7, and rest of body, gonopods and leg pair 2 dissected; the others unbroken), 2 adult ♀♀ (one in head to ring 3 and rest of body, vulvae dissected; the others unbroken), 5 juv. ♀♀ (unbroken) (all in ZMUM), ca. 50 km west of Mestia , west of Dizi, ca. 800 m a.s.l., by a waterfall, in leaf litter, 19.IX.1986, A. Ryvkin leg. ; 2 ♂♂ (one in head to ring 6 and rest of body, gonopods dissected; the other unbroken), 3 juv. (unbroken) (all in ZMUM), Mestia , 1500 m, Betula and Rhododendron on moraine, litter and under stones, 5-16.IX.1986 , SIG leg.; 1 ♂ (in head to ring 6 and rest of body), 2 ♀♀, 1 juv. ♂, 2 juv. ♀♀ (all in ZMUM), same locality as for holotype, 9.IX.1986, A. Ryvkin leg. ; 6 ♂♂ (one in 3 pieces, gonopods dissected, the others unbroken), 8 ♀♀ (two in 2 pieces, the rest unbroken), 1 juv. ♂, 4 juv. ♀♀ (all in ZMUM), Mestia , 1500 m a.s.l., litter and under stones, 22.X.1979 , SIG leg.

Diagnosis.

A species of Iraniulus differing from its only known congener, I. fagorum , by a smaller body: males <20 mm long and ca. 1 mm high, females <25 mm long and ca. 1.5 mm high, vs. males> 25 mm long and higher than 1.7 mm, females> 30 mm long and ca. 2.5 mm high in I. fagorum ), by having a proportionately shorter and stouter opisthomere, and by details of the solenomere: turned somewhat caudad, with a proportionately smaller basocaudal process, and with an apical part bearing three sharply pointed branches of equal size, vs. the same directed completely distad in I. fagorum , with a larger basocaudal process, and with an apical part ending in two short, rounded branches of equal size on the mesal side and one slender sigmoid branch on the lateral side.

Name.

Meaning three-horned in Latin, referring to the apical part of the solenomere which consists of three pointed branches. Adjective.

Description.

Measurements: holotype ♂ in S IX, 43+2+T, L = 16 mm, H = 1.05 mm; paratype ♂♂ in S VII-X, 38-43+2-3+T, L = 11-13 mm, H = 0.85-1.1 mm; paratype ♀♀ in S VII-X, 38-45+1-2+T, H = 1.2-1.6 mm, L = 14-21 mm.

Colouration: (after> 30 years in alcohol) (Fig. 9 ): mostly brown-beige; head with the usual colour pattern; antennae light brown, collum brownish, margins dark brown; prozonae dorsally with a broad, dark brown, transverse stripe next to suture, and with irregular dark brown spots just before ozopores; metazonae ochre-brown; dorsum with a continuous, blackish, axial line; legs light brown; telson brown-grey, caudal parts of paraprocts lighter.

External structures: Eye patches in adults consisting of 20-38 ommatidia arranged in hardly traceable vertical rows. Vertigial, supralabral, and labral setae: two, four, and 17-20, respectively. Antennae 1.5-1.6 × as long as head in males and ca. 1.4 × in females; antennomere 2> 5 ≥ 3 ~ 4> 6. Gnathochilarium with promentum separating both lamellae linguales in their basal 1/3-2/5, each with three setae in a longitudinal row. Collum mostly smooth, with only 2-3 short striae near posterolateral corners.

Body rings slightly vaulted. Prozonae with very short, shallow, longitudinal striae in posterior parts. Metazonae moderately deeply striated, n Schub = 7 or 8 in males and 9 or 10 in females; metazonal setae from 2/5 (in more anterior rings) to 1/2 (in more posterior rings) of metazonal length. Ozopores placed right on pro-metazonal suture in first several rings, gradually taking a more posterior position to ~ 1.5 their diameter in caudalmost rings; sutures sinuous in front of ozopores in some rings. Tarsus of mid-body legs slightly shorter than tibia and ca. 3 × as long as apical claw.

Telson (Fig. 9B ): Epiproct very long, straight, ending in a fine, tapering, hyaline tip surpassing the longest paraproctal setae in both sexes; with several long setae. Hypoproct broadly rounded in both sexes, somewhat protruding behind rear margin of paraprocts in males, tightly fitting under their ventral side in females; without setae. Paraprocts covered with sparse long setae, but without distinct rows of shorter setae along caudal margins.

Male sexual characters: Mandibular stipites (in Fig. 9A ) moderately expanded, forming a broadly rounded antero-ventral corner. Leg pair 1 compact and set parallel to hooks turned slightly mesad. Walking legs with crested adhesive pads, both tibial and prefemoral ones reduced towards telson, but still discernible in caudalmost legs; femora without modifications. Pleurotergum 7 ventrally forming relatively small shovel-like lobes (Fig. 10A ) originating mostly from metazona, directed largely ventrad. Penis (Fig. 10B ) stout, compact, nearly as broad as long, without differentiated apical lobes, but with broad and rounded terminal lamellae directed ventrad.

Gonopods (Fig. 11 ): Promere (Fig. 11B, p in Fig. 11A ) as high as opisthomere, broadest at base, somewhat narrowed distad; mesal and lateral margins gently sigmoid; apex laterally broadly rounded, mesally bearing a horn-like apicomesal process bent caudolaterad; caudal surface with a very strongly developed median ridge, a somewhat less strongly protruding lateral ridge running all the way to the top, and a relatively deep and broad median groove; a small, rounded, distomesal lobe directed mesad; flagellum somewhat longer than height of promere. Opisthomere (Fig. 11A, C-E ) relatively thick and stout; anterior process fine and tapering, bent mesocaudad; apical outgrowth of basoposterior process well-developed, protruding at nearly 90° to CBO; a faint lobe distolaterally; mesal side with a large membranous lobe, probably gonocoxal gland, at the base of seminal channel, and a deep and narrow anteromesal sinus just frontally to the membranous lobe; with a group of spiniform filaments in distal section of flagellum channel; solenomere consisting of a tapering basomesal process bent caudad and terminating both flagellum and seminal channels, a fine basocaudal process directed meso-caudad, and an apical part ending with three more or less equally sized and shaped pointed branches.

Female sexual characters: Leg pairs 1 and 2 somewhat thicker and shorter than following legs. Vulva (Fig. 10C ) roughly cylindrical, strongly transversely compressed; bursa with a well-pronounced, slightly obtuse, postero-apical margin; opening small, positioned at the very top of bursa; operculum subequal to bursa, both bursa and operculum apically bearing large hyaline protrusions; setation scattered over vulval surface. Receptaculum seminis consisting of a narrow, finger-shaped, central tube, and a very narrow, long, somewhat folded, posterior tube leading to an ovoid posterior ampulla.

General distribution.

SWGC.

Figures

Figure 9. Iraniulus tricornis sp. nov. (ZMUM) A ♂ holotype, head and body rings 1 - 4, lateral, slightly dorsal view B ♂ paratype from near Dizi, Georgia (ZMUM), telson, lateral view. Not to scale.

Figure 10. Iraniulus tricornis sp. nov., ♂ (A, B) and ♀ (C) paratypes from near Dizi, Georgia (ZMUM) A right flange of pleurotergum 7, ventro-lateral view B penis, caudal view C left vulva, caudo-lateral view. Scale bars: 0.2 mm (A, B), 0.1 mm (C). Abbreviations: ct central tube, op operculum, pa posterior ampulla, pt posterior tube.

Figure 11. Iraniulus tricornis sp. nov., gonopods of ♂ paratype from near Dizi (ZMUM) A left gonopods, mesal view B left promere, caudal view C right opisthomere, mesal, slightly oral view D left opisthomere, lateral view E right opisthomere, mesal view. Scale bars: 0.2 mm (A), 0.1 mm (B-E). Abbreviations: amp apicomesal process, ao apical outgrowth of basoposterior process, ap anterior process, aps apical part of solenomere, cps basocaudal process of solenomere, dml distomesal process, f flagellum, fc flagellum channel, g (supposed) gonocoxal gland, lp lateral lobe, lr lateral ridge, mg median groove, mps basomesal process of solenomere, mr median ridge, s solenomere, sc seminal channel, sf spiniform filaments, si anteromesal sinus.