Nepalmatoiulus lancangensis, Mikhaljova, 2024

Mikhaljova, Elena V., 2024, New species and new records of millipedes of the genera Nepalmatoiulus Mauriès, 1983 and Anaulaciulus Pocock, 1895 (Diplopoda, Julida, Julidae) from mainland China, Zootaxa 5447 (4), pp. 496-512 : 502-505

Nepalmatoiulus lancangensis sp. nov.

Figs 21–30

Material examined. Holotype: male ( ZMUM), China, Yunnan Province, SW Lanping, Qijing & Lancang div., 3.5 km ESE Tuowudi village , 26°21'23" N, 99°14'26" E, H = 3330 m, 23.05. 2018, leg. I. Belousov, I. Kabak.

Diagnosis. Differs from Chinese congeners mainly by the combination of: a strong, dentiform apically papillate mesomeral process devoid of outgrowth; presense of a notch of velum margin near mesomeral process; male coxa 2 with one mesapical oral seta anteriorly and two ones posteriorly. To a certain degree similar to Nepalmatoiulus weixi Mikhaljova, 2020a and Nepalmatoiulus jianchuanensis sp.nov. but differs from them by specific characters (see Remarks below).

Description. Male. Length in alcohol about 32.0 mm, midbody vertical diameter about 2.2 mm, with 52(- 1) rings, excluding telson. Coloration in alcohol gray with broad longitudinal slightly lighter dorsal stripe and filamentary longitudinal dark brown stripes laterally. Axial suture dark brown. Venter including basal parts of legs beige. Distal parts of legs marbled brown. Antennae brown, eyes black.

Head smooth, group of setae on each lateral side (below of antenna), 2 epicranial setae, 4 supralabral setae; at least 28 labral setae. Eye patches almost oval, composed of about 50 ommatidia. Antennae medium-sized, rather slender and clavate. Antennomeres 5 and 6 with incomplete distodorsal corolla of sensilla basiconica. Mandibular stipites with subtriangular smooth lobes. Gnathochilarium with not less than 12 nonapical stipital setae; lamellae linguales each with 7–8 setae arranged longitudinally. Collum laterally with distinct striae of different length at posterior margin not reaching to anterior margin, dorsally with distinct short striae at posterior margin. A transverse row of very sparse thin setae at hind edge of collum.

Body rings circular. Metazona with dense, regular, longitudinal striae reaching hind margin (16–18 striae in an approximate square with sides equal to metazonital length of a dorsal side of a midbody ring). Limbus straight, smooth (of Type 1 in Enghoff 1987). A transverse row of sparse, thin setae at hind edge of metazonites, setae gradually growing denser and longer toward telson. Ozopores small, lying behind suture between pro- and metazona without touching it. Caudal dorsal projection of telson straight and long, covered with setae and carrying at tip a claw-shaped process curved dorsally. Preanal ring and subanal scale setose, anal valves densely setose.

Legs relatively short and slender. Very delicately serrate ventral pads present on postfemur and tibia, starting from legs 2. Claw of all legs at base with a long (longer than claw) setiform accessory claw ventrally. Leg pair 1 forming hook, the distal podomere not coming into close contact with the basal podomeres (“open hook” type in Enghoff 1987); postfemur with inflated scaly-rugose ventral surface, tip indistinctly wrinkled, coxa with one seta, distal podomere without seta, with low seta tarsal remnant ( Fig. 24 ). Coxa 2 with one long mesapical oral seta anteriorly ( Fig. 22 ) and shorter two ones posteriorly ( Fig. 21 ), gland opening positioned in apical and axial position sensu Enghoff (1987). Penis subrectangular, about 1.8 times longer than wide ( Fig. 23 ).

Gonopods slightly protruding. Anterior gonopod flattened, with parallel margins, apically obliquely rounded, in posterior view apically excavated for accommodation of mesomeral process, distal margins of the excavation papillate, rudimentary telopodite with seta and small protrusion ( Fig. 25 ). Flagellum slender, of medium length, caudally covered with cuticular conical spikes ( Figs 29–30 ). Opisthomere with strong, dentiform mesomeral process slightly arched forward, its apex covered with papillae ( Figs 26–27 ). Margin of velum smooth, arcuate, with a notch near the mesomeral process. Solenomere twisted to the mesal side. It relatively short and broad, with dense long thin spines basally, spinose arteriorly ( Fig. 28 ).

Etymology. The specific epithet refers to the type locality, Lancang. Adjective.

Remarks. It is possible to assume that the twist of the solenomere on the mesial side occurred due to mechanical pressure during collection of the material (not during preparation because the holotype that came to me was intact and undestroyed but already had a twisted solenomere). However, this circumstance is not decisive and has no diagnostic significance, therefore it does not affect the independence of the new species in any way; the independence of the new species is not in doubt, taking into account the main distinctive characters.

Nepalmatoiulus lancangensis sp. nov. differs from N. weixi and N. jianchuanensis sp. nov. mainly by the larger body length (about 32.0 mm) and midbody vertical diameter (about 2.2 mm) (vs. length—about 26.0–27.0 mm, midbody vertical diameter—about 1.0 mm in N. weixi ; length—about 22.0 mm, midbody vertical diameter—about 1.9 mm in N. jianchuanensis sp. nov.), by the gray body coloration (vs. marbled brown in N. weixi and brown-gray in N. jianchuanensis sp.nov.), by the solenomere shifted forward with a twist to the mesal side (vs. the solenomere not twisted mesally, and a notch between velum and solenomere broad, ovale in N. weixi and narrow ovale in N. jianchuanensis sp.nov.), by the presense of a velum noch near apex of the mesomeral process (vs. the absence of a notch in N. jianchuanensis sp. nov.), by the subtriangular lobes of the mandibular stipites (vs. ovale ones in N. jianchuanensis sp. nov.), by the male coxa 2 with two mesapical oral setae posteriorly (vs. one mesapical oral seta posteriorly in N. jianchuanensis sp. nov.).

Figures

FIGURES 21–24. Nepalmatoiulus lancangensis sp. nov., male holotype (ZMUM). 21. Coxa 2, posterior view. 22. Coxae 2, anterior view. 23. Penis, posterior view. 24. Leg pair 1, anterior view. Scales: 20 μm (Fig. 23), 100 μm (Fig. 24).

FIGURES 25–30. Nepalmatoiulus lancangensis sp. nov., male holotype (ZMUM). 25. Right promere, posterior view. 26. Opisthomere, mesal view. 27. Opisthomere, mesal view (slightly turned forward). 28. Solenomere. 29. Flagellum apex. 30. Part of flagellum. Scales: 2 μm (Fig. 30), 10 μm (Fig. 29), 20 μm (Fig. 20), 100 μm (Figs 25, 26, 27).