Nepalmatoiulus simultaneus, Mikhaljova, 2023

Mikhaljova, Elena V., 2023, Descriptions of the new species of the genus Nepalmatoiulus Mauriès, 1983 from China, with notes on the closely coexisting species (Diplopoda, Julida, Julidae), Zootaxa 5297 (3), pp. 380-392 : 385-387

Nepalmatoiulus simultaneus sp. nov.

Figs 15–26 , 39

Material examined. Holotype: male (dissected) ( ZMUM), China, Yunnan Province, Laojunshan E slope of Laotzyunshan Mt. , 26°52´58´´ N, 99°37´44´´ E, H = 4075 m, crooked Rhododendron forest, wet litter + numerous streams, sifter, 05.06.2014, leg. I. Belousov, I. Kabak. Paratypes: 1male (dissected) ( FSCB) , 3 females (one of them dissected) ( ZMUM), same data as for holotype .

Diagnosis. Differs from congeners mainly by the presence of the strongly papillate cone-shaped subapical outgrowth (d in Figs 20 , 23 ) of the posterior gonopod mesomeral process and the absence of the velar process coupled with the apically obliquely rounded anterior gonopod and subrectangular penis. Particularly similar to Nepalmatoiulus lanpingensis and Nepalmatoiulus alternus sp. nov., but differs from these species by certain characters (see Discussion below).

Description. Male. Length in alcohol 27.0–30.0 mm, midbody vertical diameter 2.0– 2.2 mm, with 56(–1) (in a male holotype), 48(–1) rings, excluding telson. Coloration in alcohol from dark brown-grey to brown-gray with broad light longitudinal dorsal strip formed by lighter dorso-anterior metazonital portions. Venter (including basal parts of legs) brown. Legs dorsally and antennae dark brown. Occiput, forehead and collum from black brown to dark brown, ventral parts of head light brown. Eyes black.

Head smooth and sparsely setose, 2 epicranial setae, 4 supralabral setae; not less than 12 labral setae in the paratype. Eye patches almost oval, composed of not less than 43 ommatidia.Antennae medium-sized, rather slender and clavate. Gnathochilarium with no less than 8 nonapical stipital setae; lamellae linguales each with not less than 6 (in the paratype) setae; mandibular stipites each with subtriangular rounded smooth lobe; apical portion of the lobe without well demarcated border.

Collum laterally with several distinct longer lower striae at posterior margin, not reaching to anterior margin, dorsally with short striae at posterior margin only. Length of the collum striae gradually decreasing toward dorsum. A transverse row of sparse setae at hind edge of collum. Body rings circular.Anterior body half with smooth prozona. Prozona of posterior body half generally smooth, but with barely noticeable, very shallow obliquely located striae. Metazona with dense, regular, longitudinal striae reaching hind margin (16 or 17 striae in an approximate square with sides equal to metazonital length of a dorsal side of midbody ring). Metazonite gradually growing somewhat narrower toward body venter. Limbus straight, smooth (of Type 1 in Enghoff 1987). A transverse row of thin setae at hind edge of metazonites, setae gradually growing longer and denser toward telson. Ozopores small, lying immediately behind suture dividing pro- and metazona. Caudal dorsal projection of telson straight and long, covered with setae and carrying at tip a claw-shaped process curved dorsally. Preanal ring setose; anal valves densely setose distally; subanal scale densely setose only in posterior half.

Legs relatively short and slender. Very delicately serrate ventral pads on postfemur and tibia, starting from legs 2 ( Fig. 17 ). The ventral pads gradually decrease towards telson; tibia of most hind legs with ventral pads on distal part only. Claw of all legs at base with a long (somewhat longer than claw) setiform accessory claw ventrally ( Fig. 18 ). Leg pair 1 forming hook, distal segment not in close contact with the basal segments (“Open hook” type in Enghoff 1987). Leg pair 1: postfemur with slightly scaly-rugose ventral surface; tip ventrally slightly rugosity; coxa with one seta; distal segment laterally with small seta, without tarsal remnant ( Fig. 15 ). Coxa 2 with one mesapical oral seta, a gland opening positioned in central and axial position ( Fig. 17 ) according to Enghoff 1987. Penis subrectangular, about 2.2 longer than wide ( Fig. 16 ). Ventral margin of body ring VII with lobes similar to figure 32 in Enghoff 1987.

Gonopods slightly protruding. Anterior gonopod flattened, with subparallel margins, distally slightly expanded, apically relatively obliquely rounded, in caudal view subapically excavated for accommodation of mesomeral process, distal margins of the excavation papillate (especially mesal margin), rugose margin of apical excavation somewhat produced into low short blunt caudad protrusion (a), subcentrally with knoblike flattened rudimentary telopodite ( Figs 21–22, 24–25 ). In addition, anterior gonopod apex shows some variation. Thus, male paratype has a more rounded anterior gonopod apex and a more extensive papillary field ( Figs 21, 24 ) than that of male holotype ( Figs 22, 25 ). Flagellum slender, short, caudally covered with cuticular spikes in the distal part. Opisthomere with apically hook-shaped mesomeral process and subapical, cone-shaped, apically strongly papillate outgrowth (d) ( Figs 20 , 23 ). Membranous velum with not very sloped smooth margin. Margin of accessory membrane (m) serrate ( Figs 23, 26 ). Long and slender solenomere spinose anteriorly.

Female. Length in alcohol 30.0–35.0 mm, midbody vertical diameter 3.2– 3.5 mm, with 58(–1), 51(–1), 47(–1) rings, excluding telson. Vulva as in Fig. 19 .

Etymology. The species epithet refers to the simultaneous finding of specimens of N. simultaneus sp. nov. and N. alternus sp. nov. Adjective.

Figures

FIGURE 39. Size relations of coexisting Nepalmatoiulus alternus sp. nov. (continuous lines, square - ♁, diamond - ♀) and Nepalmatoiulus simultaneus sp. nov. (stippled lines, heart - ♁, oval - ♀). H, midbody vertical diameter (mm), p.s., number of podous rings.

FIGURES 15–20. Nepalmatoiulus simultaneus sp. nov., male (Figs 15–18, 20, FSCB) and female (Fig. 19, ZMUM) paratypes. 15. Leg pair 1, anterior view. 16. Penis, caudal view. 17. Leg pair 2, anterior view. 18. Claw 2, anterior view. 19. Left vulva, lateral view. 20. Opisthomere, anteromesal view. Abbreviation: d, outgrowth of mesomeral process. Scales: 10 μm (Fig. 18), 20 μm (Figs 15–16), 100 μm (Figs 17, 19), 0.5 mm (Fig. 20).

FIGURES 21–26. Nepalmatoiulus simultaneus sp. nov., male holotype (ZMUM) and male paratype (FSCB). 21. Left promere of male-paratype, caudal view. 22. Left promere of male-holotype, caudal view. 23. Opisthomere, mesal view. 24. Distal part of left promere of male-paratype, caudal view. 25. Distal part of left promere of male-holotype, caudal view. 26. Velum, solenomere and accessory membrane. Abbreviations: a, protrusion; d, outgrowth of mesomeral process; m, accessory membrane. Scales: 10 μm (Fig. 24), 20 μm (Figs 25–26), 100 μm (Figs 21–23).