Nepalmatoiulus alternus, 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 : 381-385

Nepalmatoiulus alternus sp. nov.

Figs 1–14 , 39

Material examined. Holotype: male ( 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, 1female (dissected) ( ZMUM) , 1 male (dissected) ( FSCB), same data as for holotype .

Diagnosis. Differs from congeners mainly by the relatively flattened apical part of the opisthomere mesomeral process with a longitudinal frontal, distinct broad excavation (ex in Figs 11, 14 ), by the relatively broad, somewhat flattened subapical outgrowth (d in Figs 11–12, 14 ) of the mesomeral process and the absence of the velar process coupled with the apically broadly rounded, slightly obtuse promere and penis as hourglass figure. Particularly similar to Nepalmatoiulus lanpingensis Mikhaljova and Nepalmatoiulus simultaneus sp. nov., but differs from these species by certain characters (see Discussion below).

Description. Male. Length in alcohol 31.0–34.0 mm, midbody vertical diameter 2.3– 2.7 mm, with 57(–1) (in a male holotype), 55(–1), 52(–1) rings, excluding telson. Coloration in alcohol dark grey; sometimes posterior body half with hardly lighter dorso-anterior metazonital portions. This portions not visible in dried specimen. Venter (including basal parts of legs) black-brown.Anterior several rings (7–8) of the usual julid type pattern. Legs dorsally and antennae dark brown. Occiput and forehead marbled brown, ventral parts of head light brown. Eyes black.

Head smooth and sparsely irregularly setose (in the form of blurred individual groups of setae), 2 epicranial setae, 4 supralabral setae; not less than 18 labral setae in one of the paratypes. Eye patches almost oval, composed of about 50 ommatidia (47–48 ommatidia in one of the paratypes). Antennae medium-sized, rather slender and clavate. Gnathochilarium with no less than 14 nonapical stipital setae; lamellae linguales each with not less than 6 setae; mandibular stipites each with a 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 collum striae gradually decreasing toward dorsum. A transverse row of sparse setae at hind edge of collum. Body rings circular. Prozona generally smooth, but with barely noticeable, very shallow obliquely located striae. Metazona with dense, regular, longitudinal striae reaching hind margin (18 or 19 striae in an approximate square with sides equal to metazonital length of a dorsal side of midbody ring). The metazonite gradually growing somewhat narrower towards 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; 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. 2 ). Claw of all legs at base with a long (somewhat longer than claw) setiform accessory claw ventrally ( Fig. 4 , the setiform accessory claw is bent in this Figure). Leg pair 1 forming hook, the 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 without tarsal remnant ( Fig. 1 ). Coxa 2 with one mesapical oral seta, a gland opening positioned in central and axial position ( Fig. 3 ) according to Enghoff 1987. Penis as hourglass figure, about 1.8 longer than wide ( Fig. 6 ). 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 broadly rounded, slightly obtuse, in posterior 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 7–10 ). In addition, apex of anterior gonopod variable even within same male paratype: lateral angle (la) of top of right promere ( Fig. 10 ) more elongated than that of left promere ( Fig. 9 ). Flagellum slender, short, caudally covered with cuticular spikes in distal part. Opisthomere hook-shaped mesomeral process apically with longitudinal frontal broad excavation (ex); mesal margin of excavation with small knobs (k); subapical mesomeral outgrowth (d) somewhat flattened, apically poorly papillate ( Figs 11–12, 14 ). Membranous velum with strongly sloped smooth margin. Margin of accessory membrane serrate. Solenomere spinose, basally with blade (bb), then tapering into slender apical part spinose anteriorly ( Figs 11, 13 ).

Female. Length in alcohol about 31.0 mm, midbody vertical diameter 2.4 mm, with 48(–1) rings, excluding telson. Vulva as in Fig. 5 .

Etymology. The specific epithet refers to the alternation of Nepalmatoiulus species. 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 1–5. Nepalmatoiulus alternus sp. nov., male (Figs 1–4, FSCB) and female (Fig. 5, ZMUM) paratypes. 1. Leg pair 1, anterior view. 2. Leg 2, anterior view (mesapical oral seta broken off). 3. Coxae 2, anterior view. 4. Claw 2, anterior view. 5. Left vulva, caudal view. Scales: 10 μm (Fig. 4), 20 μm (Fig. 1), 100 μm (Figs 2–3, 5).

FIGURES 6–10. Nepalmatoiulus alternus sp. nov., male paratype (FSCB). 6. Penis, caudal view. 7. Left promere, caudal view. 8. Right promere, caudal view. 9. Distal part of left promere, caudal view. 10. Distal part of right promere, caudal view. Abbreviations: a, protrusion; la, lateral angle. Scales: 20 μm (Figs 6, 9–10), 100 μm (Figs 7–8).

FIGURES 11–14. Nepalmatoiulus alternus sp. nov., male paratype (FSCB). 11. Opisthomere, mesal view. 12. Anterior part of opisthomere, mesal view. 13. Solenomere. 14. Opisthomere, anteromesal view. Abbreviations: bb, basal blade of solenomere; d, outgrowth of mesomeral process; ex, excavation; k, knobs. Scales: 10 μm (Figs 12–13), 100 μm (Fig. 11), 0.5 mm (Fig. 14).