Leptoiulus hebeiensis Mikhaljova, 2025

Leptoiulus hebeiensis Mikhaljova sp. nov.

Figs 1–13 View FIGURES 1–6 View FIGURES 7–13

Material examined. Holotype: male ( ZMUM), China, Hebei Province, Xiaowutai Mt. , 40.025° N, 115.303° E, 19.09.2005, leg. Y. M. Marusik GoogleMaps ; Paratypes: 4 males, 1 female, 1 juvenile ( FSCB) , 1 male, 2 females, 2 juveniles ( ZMUM), same data as for the holotype .

Diagnosis. Differs from congeners mainly by the gonopod opisthomere with the phylacum pressed to its adjacent part along the entire length, by the absence of a basal outgrowth on the gonopod promere, and by the presence of the telopodite remnant of the promere.

Description. Male. Length 18–19 mm, midbody vertical diameter 0.8–0.9 mm, with 49(–2) (holotype), 48(–2) and 49(–3) (3 of the paratypes; remaining paratypes are broken) rings, excluding telson. Coloration (in alcohol) dark brown; venter including basal parts of legs brown. Distal parts of legs dark brown. No pronounced colour pattern. Only head, collum and 1–2 subsequent rings of the usual julid type (according to Enghoff 1982) but weakly appearing. Eye patches black. Antennae brown.

Head smooth, 2 epicranial setae, 4 supralabral setae; about 30 labral setae in one of the paratypes. Eye patches subtrapezoidal, composed of not less 40 ommatidia (40–42 ommatidia in one of the paratypes). Antennae mediumsized, rather slender and clavate, reaching the middle of the body ring 3 when folded back. Antennomeres 5, 6 and 7 with incomplete distodorsal corolla of sensilla basiconica; sensilla basiconica of the antennomere 7 minute ( Fig. 5 View FIGURES 1–6 ). Mandibular stipites without modification. Collum smooth, laterally with barely noticeable striae of different lengths at the posterior margin which are not reaching anterior margin, dorsally with barely noticeable short longitudinal striae at posterior margin. A transverse row of very sparse thin setae at hind edge of collum. Gnathochilarium distally with 2 setae on frontal-outer edge of each stipites, with one seta closer to medial portion and with low papillate swelling at the frontal part as well as with a small group of short setae (gs) approximately in the middle of the stipites ( Fig. 2 View FIGURES 1–6 ). Each lamella lingualis (ll) with 5 setae arranged longitudinally; length of setae increasing towards apex of lamellae linguales.

Body rings circular. Prozona smooth. Metazona with regular longitudinal striae not reaching hind margin (7–8 striae in an approximate square with sides equal to metazonital length of a dorsal side of midbody ring). Transverse row of sparse, thin setae at hind edge of metazonites, setae gradually growing longer and denser toward telson. Ozopores small set off behind from suture dividing pro- and metazona. Caudal dorsal projection of telson short, round in cross-section and supplied with a tiny claw-shaped process directed caudad. Preanal ring setose; anal valves and subanal scale densely setose.

Legs slender, moderately long. Claw at base with a long (longer than claw) setiform accessory claw ventrally ( Fig. 3 View FIGURES 1–6 ). Very delicately serrated ventral sole pads on postfemur and tibia, starting from legs 2. Ventral pads gradually decreasing towards telson. Leg pair 1 unciform, with sparse and low papillae apically; ventrally 2-segmented telopodites with low, knob-shaped protrusions (p) carrying strong setae ( Fig. 1 View FIGURES 1–6 ). Each coxa of leg pair 1 with a disto-mesal seta. Leg pair 2 slightly reduced in size compared to other legs, penes subrectangular, apically double.

Gonopod promere and mesomere closely attached to each other ( Fig. 8 View FIGURES 7–13 ). Coxosternal region poorly developed. Promere flattened, caudally papillate, with rounded apical part and flagellum (f) and remnant of a telopodite (t) ( Fig. 4 View FIGURES 1–6 ). Flagellum slender, whip-shaped, covered with cuticular spikes in its distal part ( Fig. 6 View FIGURES 1–6 ). Mesomere (m) somewhat expanded distally, distal portion frontally with a spoon-shaped excavation (se) covered with papillae ( Figs 7, 8, 11, 13 View FIGURES 7–13 ). Opisthomere slender, with somewhat bifurcated apically phylacum (ph) pressed to the adjacent part of the opisthomere along the entire length, as well as a claw-shaped velum (v) in front of an apical process, interior parabasal spine (s) ( Figs 7, 9, 12 View FIGURES 7–13 ).

Female. Length 22–25 mm, midbody vertical diameter 1.3–1.5 mm, with 49(–2), 50(–2) (2 of the paratypes; remaining paratype is broken) rings, excluding telson. Vulva as in Fig. 10 View FIGURES 7–13 . Operculum apically with excavation; posterior median bursal sclerite with strong setae, median cleft deep.

Etymology. The specific epithet name refers to the type locality, Hebei Province, adjective.

Remarks. Leptoiulus hebeiensis sp. nov. is similar to L. tigirek Mikhaljova, Nefediev, Nefedieva & Dyachkov, 2015 known from the Altai in the general configuration of gonopods, but differs from it mainly by the gonopod phylacum (ph) pressed to the adjacent part of the opisthomere along the entire length (vs. the apical part of phylacum not pressed against the adjacent part of the opisthomere in L. tigirek ), by the presence of the telopodite remnant on the gonopod promere (gonopod promere lacking telopodite remnant in L. tigirek ), by the rounded apical part of the gonopod promere (vs. apical part of the gonopod promere narrowed, almost triangular in L. tigirek ), by a smaller body size: length 18–19 mm, midbody vertical diameter 0.8–0.9 mm in male, 22–25 mm and 1.3–1.5 mm relatively in female (vs. in L. tigirek : length 20–28 mm [males with a body length 24–25 mm are more common], vertical diameter 1.1–1.3 mm in male, length 18–36 mm [females with body length 31–33 mm are more common], vertical diameter 1.4–2.2 mm in female).