Spinaxytes sutchariti Srisonchai, Enghoff & Panha

Srisonchai, Ruttapon, Enghoff, Henrik, Likhitrakarn, Natdanai & Panha, Somsak, 2018, A revision of dragon millipedes IV: the new genus Spinaxytes, with the description of nine new species (Diplopoda, Polydesmida, Paradoxosomatidae), ZooKeys 797, pp. 19-69: 19

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Spinaxytes sutchariti Srisonchai, Enghoff & Panha

sp. n.

Spinaxytes sutchariti Srisonchai, Enghoff & Panha  sp. n. Figs 4P, Q; 5G; 24; 25

Material examined.

Holotype. ♂, THAILAND, Krabi Province, Muang Krabi District, Tham Na Mee (Na Mee Cave), 8°08'12"N, 98°48'23"E, ca. 70 m a.s.l., 31 Aug. 2015, C. Sutcharit leg. (CUMZ-pxDGT00217). Paratypes. 7 ♂♂, 4 ♀♀, same data as for holotype (CUMZ-pxDGT00218).


The name honours associate professor Dr. Chirasak Sutcharit, malacologist of ASRU (CUMZ), collector of this new species and numerous other dragon millipedes.


Male femora without modification, sternal lobe between male coxae 4 incompletely bilobed. Similar in these respects to S. palmata  sp. n., but differs by having: a large and round lamina lateralis; tip of lamina medialis terminating in two spines; distal part of solenomere circular in tranverse section.


SIZE. Length 20-25 mm (male), 23-27 mm (female); width of midbody metazona 1.5-1.8 mm (male), 1.9-2.2 mm (female). Width of collum = 2 = 3 = 4 < head = 5-16, thereafter body gradually tapering towards telson.

Colour (Figure 24 A–C). Specimens in life with body black; paraterga brownish white; head, antennae (except whitish distal part of antennomeres 7 and 8), collum, prozona, metaterga and epiproct black; surface below paraterga black/brownish black; sterna brown; legs brown/blackish brown; a few basal podomeres whitish brown.

Antennae. Reaching to body ring 8 or 9 (male) and 6 (female) when stretched dorsally.

Collum. With three transverse rows of setiferous tubercles, 4+4 tubercles in anterior row, 1+1 tubercles in intermediate row and 2+2 tubercles in posterior row; with one inconspicuous setiferous notch at lateral margin; paraterga spiniform, quite short, tip sharp, elevated at ca. 15°-20° in both male and female, directed caudolaterad.

Tegument. Quite dull; collum and metaterga (posterior part) coarsely microgranulate; metaterga (anterior part) and surface below paraterga smooth.

Metaterga. With two transverse rows of setiferous tubercles and setiferous spines; metaterga 2-19 with 2+2 tubercles in anterior row and 2+2 spines in posterior row; lateral spines of posterior row bigger and longer than mesal ones, subequal in size and length on all body rings.

Paraterga. Long; directed dorsolaterad on body rings 2-16, elevated at ca. 45°-50° (male) 40°-50° (female), directed dorsocaudad on ring 17, directed increasingly caudad on body rings 18 and 19. Ozopore visible in lateral view.

Telson. Epiproct quite long; tip subtruncate; lateral setiferous tubercles conspicuous; apical tubercles inconspicuous. Hypoproct subtrapeziform (in some specimens subtriangular); caudal margin round (in some specimens angular), with inconspicuous setiferous tubercles.

Sterna (Figure 4P). Sternal lobe between male coxae 4 incompletely bilobed; tips sharp, in situ directed laterad; posterior surface bearing 2 pores.

Legs (Figure 4Q). Male femora without modification.

Gonopods (Figs 5G, 25). Coxa subequal in length to femur. Prefemoral part ca. 2/3 as long as femur. Femur not enlarged distally. Postfemoral part narrow. Mesal sulcus and lateral sulcus wide. Solenophore bigger and longer than postfemoral part: lamina lateralis oval, large, long, tip round: lamina medialis long and slender; base enlarged, slightly attenuated near the tip; tip curving down, with two sharp spines (one smaller, one bigger). Solenomere curving up, circular in transverse section, tip directed anteriad.

Distribution and habitat

(Figure 24D). S. sutchariti  sp. n. is known only from the type locality, and we regard it as endemic to Thailand. The new species can be found in the same area as Gigaxytes gigas  , but we assume that they live in different microhabitats: G. gigas  was collected from the ground in leaf litter, whereas the new species was found on humid rock walls.


We found variation in the hypoproct: in some specimens subtrapeziform, in others subtriangular; caudal margin in some individuals round, in others angular. Parasitic mite larvae, probably of the genus Leptus  Latreille, 1796, were found attached to the anterior body part of some female specimens. Larvae of ? Leptus  have previously been found on species of Desmoxytes  ( D. cervina  ) and Nagaxytes  ( N. acantherpestes  (Golovatch & Enghoff, 1994)) ( Srisonchai et al. 2018a, 2018b, see also Southcott 1992).