Nepalmatoiulus acutidentatus, Mikhaljova, 2020

Mikhaljova, Elena V., 2020, New data on the fauna of China, part II: the millipede genus Nepalmatoiulus Mauriès, 1983 (Diplopoda, Julidae) in continental China and Taiwan, with descriptions of seven new species, Zootaxa 4852 (1), pp. 101-124 : 114-116

Nepalmatoiulus acutidentatus , new species

Figs 52–61

Material examined. Holotype: male ( ZMUM), China, Yunnan Province, NE Weixi City, 4.4 km ESE Rilidi , 27°18´15´´ N, 99°24´0´´ E, H = 3655 m, 10 June 2015, leg. I. Belousov, I. Kabak, G. Davidian ; Paratype: 1 female ( ZMUM), same locality as in holotype, 10 June 2015, leg. I. Belousov, I. Kabak, G. Davidian.

Diagnosis. Differs from congeners mainly by the straight pointed gonopod mesomeral process with subapical mesal subtriangle outgrowth and the absence of velar process coupled with a short and broad solenomere covered with relatively long setae. Particularly similar to Nepalmatoiulus deqenensis sp. nov., but differs from it mainly by the longer body, uniform dark gray body coloration without light broad longitudinal dorsal strip, a more pointed and straight gonopod mesomeral process, more broad solenomere and distally expanded anterior gonopods.

Description. Male. Length about 30 mm, midbody vertical diameter 1.7–1.9 mm, with 51 (–1) segments, excluding telson. Coloration (in alcohol) uniform dark gray. Anterior and ventral parts of head light brown. Antennae dark brown, legs brown, eyes black. Head smooth and sparsely setose. 2 epicranial setae, 4 supralabral setae; not less than 14 labral setae. Eye patches almost oval, composed of about 50 ocelli. Antennae medium-sized, rather slender and clavate. Gnathochilarium with no less than 10 nonapical stipital setae. Mandibular stipite with subrectangular rounded smooth lobe; apical portion of the lobe with well demarcated border; 5–7 setae on each lamella linguales. Collum laterally with several distinct long lower striae extending from posterior 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 segments circular. Prozona smooth. Metazona with dense, regular, longitudinal striae reaching hind margin (17–18 striae in an approximate square with sides equal to metazonital length of a dorsal side of midbody ring). Limbus straight, smooth (of Type 1 in Enghoff 1987). The metazonite gradually growing narrower toward venter. A transverse row of thin setae at hind edge of metazonites, setae gradually growing denser toward telson. Ozopores small, lying immediately behind suture dividing pro- and metazona. Caudal dorsal projection of telson long, covered with setae and carrying at tip a claw-shaped small process directed caudad. Preanal ring setose, anal valves, and subanal scale 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 relatively long (longer than claw) setiform accessory claw ventrally but without accessory claw dorsally. Leg pair 1 forming hook, the distal segment not touching basal segments (“Open hook” type in Enghoff 1987); postfemur with slightly scaly-rugose ventral surface, tip indistinctly wrinkly; coxa with one seta, distal segment with very small tarsal remnant and without seta ( Fig. 52 ). Coxa 2 with one mesapical oral seta, a gland opening positioned in central and axial position according to Enghoff 1987 ( Fig. 53 ). Penis relatively short, about 1.3 longer than wide ( Fig. 56 ). Ventral margin of body segment VII with lobes similar to figure 32 in Enghoff 1987. Gonopods slightly protruding. Anterior gonopod flattened, with subparallel margins, distally somewhat expanded, apically rounded, in posterior view subapically excavated for accommodation of mesomeral process, distal margins of the excavation papillate (especially mesal margins), rugose margin of apical excavation produced into short blunt caudad protrusion (a), subcentrally with knoblike flattened rudimentary telopodite ( Figs 54–55 ). Flagellum slender, relatively short, covered with cuticular spikes in the distal part; the basal part of the flagellum is probably without protrusions (failed to see the protrusions of the flagellum). Opisthomere with pointed mesomeral process and strong subapical mesal subtriangle outgrowth ( Figs 58, 60–61 ). Membranous velum with arcuate smooth margin, without a notch near the mesomeral process. Solenomere short, broad, covered with relatively long setae ( Fig. 59 ). Margin of accessory membrane slightly undulated. A flap arising from posterior margin of the solenomeral furrow with distinct pointed process (f).

Female. Length about 34 mm, midbody vertical diameter about 2.0 mm, with 50 (–1) segments, excluding telson. Gnathochilarium without nonapical stipital setae. Vulva with operculum higher than bursa ( Fig. 57 ). Apical hyaline lobes of bursa not long.

Etymology. The specific epithet refers to the pointed dentiform gonopod mesomeral process.

Figures

FIGURES 52–57. Nepalmatoiulus acutidentatus sp. nov., male holotype, female paratype. 52, leg 1; 53, coxae 2, front view; 54, promere, caudal view; 55, distal part of promere; 56, penis; 57, vulva, caudal view; a, protrusion. Scales: 20 μm (Figs 52, 55–56), 100 μm (Figs 53–54, 57).

FIGURES 58–61. Nepalmatoiulus acutidentatus sp. nov., male holotype. 58, opisthomere, mesal view; 59, solenomere; 60, distal part of mesomeral process; 61, apex of mesomeral process; f, process of a flap arising from posterior margin of the solenomeral furrow. Scales: 10 μm (Figs 59, 61), 20 μm (Fig. 60), 100 μm (Fig. 58).