Orthomorpha alutaria, Likhitrakarn, Natdanai, Golovatch, Sergei I. & Panha, Somsak, 2010

Likhitrakarn, Natdanai, Golovatch, Sergei I. & Panha, Somsak, 2010, The millipede genus Orthomorpha Bollman, 1893 in Thailand. 1. Revision of the sericata - group, with descriptions of four new species (Diplopoda, Polydesmida, Paradoxosomatidae), Zootaxa 2361, pp. 23-45 : 32

Orthomorpha alutaria sp. n.

Figs 3 E & F, 7 & 8.

Material examined: Holotype male ( CUMZ), Thailand, Lop Buri Province, Khok Samrong District, Khao Wong Phrachan Temple, 14°58´0˝N, 100°41´49˝E, 8 August 2008, leg. S. Panha and members of Animal Systematics Research Unit. Paratypes: 14 males, 3 females ( CUMZ), 2 males, 1 female ( ZMUC), 2 males, 1 female ( ZMUM), same data as holotype. 1 male, Thailand, Uthai Thani Province, Lan Sak District, Thep Mueang Thong Temple, 15°24´59˝N, 99°35´37˝E, 7 June 2008, leg. C. Sutcharit. 1 female ( CUMZ), same Province, Thap Than District, Khao Patawe Temple, 15°28´31˝N, 99°45´28˝E, 13 June 2006, leg. S. Panha and members of Animal Systematics Research Unit. 1 female, same Province, Ban Rai District, Tham Khao Wong Temple, 15° 1´59.82˝N, 99°27´18.42˝E, 8 July 2009, leg. C. Sutcharit.

Name: To emphasize the smooth, leathery tegument both of prozona and metaterga.

Diagnosis: Differs from congeners in the dull, microgranulate tegument, primarily the vertex and metaterga, combined with the evident frontal incision on the paraterga and the lower setigerous knobs on the metaterga, albeit these are not as strongly developed as those in O. enghoffi sp. n., and in the irregularly axeshaped tip of the solenophore (much as in O. enghoffi sp. n.).

Description: Length 22–27 mm (male), 23–27 mm (female), width of midbody pro- and metazona 1.9– 2.1 and 3.2–3.9 mm (male), 2.3–2.6 and 3.3–4.0 mm (female), respectively in most specimens. One paratype (male from Thep Muang Thong) 22 mm long, 1.6 and 2.8 mm wide on pro- and metazona, respectively. Holotype 26 mm long, 2.1 and 3.3 mm wide on pro- and metazona, respectively. Live coloration ( Fig. 7 A) blackish-brown, head and antennae blackish as well, paraterga and epiproct contrastingly pale orange, legs brownish; coloration in alcohol ( Figs 7 B–J) blackish-brown, head and antennae dark brown, paraterga and epiproct contrastingly yellow, legs and venter light grey-brown.

Main characters as in O. enghoffi sp. n., except as follows.

Vertigial part sparsely setose. Collum with 3rd row of setae not borne on knobs; paraterga small, caudally narrowly rounded, obtusangular, declined flaps ( Fig. 7 C).

Tegument smooth and dull, prozona and metaterga delicately leathery ( Figs 7 A–J), only hind edge of metaterga in places microgranulate to rugulose; surface below paraterga finely microgranulate and in places often rugulose as well. Metaterga with two transverse rows of setae, pattern traceable as 2+ 2 in anterior row without knobs and 2(3)+2(3) in posterior row, borne on tiny knobs at rear edge of metaterga. Tergal setae much shorter, about as long as 1/6–1/4 of metazonum, usually retained only in anterior row. Paraterga welldeveloped ( Figs 7 B–H), usually slightly upturned to subhorizontal, paraterga 3–7 lying about level to, others usually only slightly below dorsum (male), or all paraterga lying below dorsum (female). Anterior edge of paraterga 2 and 3 strongly convex and bordered, of paraterga 4–8 slightly convex. Lateral edge of paraterga 2 with 2–3 incisions in anterior half ( Fig. 7 B). Lateral edge of paraterga 3 and 4 with slightly less evident incisions ( Fig. 7 B). Lateral incisions on paraterga 5–16 stronger than those in O. subsericata , but usually less strong than in O. enghoffi sp. n. Caudal edge of paraterga usually slightly fringed or with small notches, sometimes with traces of a midway lobule ( Fig. 7 D). Posterior edge of poreless paraterga more concave. All paraterga behind collum at least very slightly surpassing tergal contour. Ozopores evident, lateral. Transverse sulcus barely traceable, incomplete on segments 4 and 18, complete on metaterga 5–17, superficial, lineshaped, reaching bases of paraterga, finely, and only at places, beaded at bottom ( Figs 7 B & D). Pleurosternal carinae traceable only as small, caudal, sharp tooth on segments 2–7 ( Fig. 7 C), as faint tubercle on segment 8 (male), or as faint caudal tubercle only on segments 2–8 (female). Tip of epiproct often more broadly emarginate than in O. enghoffi sp. n. ( Figs 7 F & G). Ridge in front of gonopod aperture lower, not as prominent as in O. enghoffi sp. n. Sternal lamina between male coxae 4 as pair of low, bilobate cones ( Figs 7 I & J). Legs a bit shorter than in O. enghoffi sp. n., about 1.4 (male) or 1.2 times (female) as long as midbody height; male legs 1 and 2 with incomplete tarsal brushes.

Gonopods ( Figs 3 E & F, 8) much like in O. enghoffi sp. n., but tip slightly more axe-shaped.

Figures

FIGURE 3. Orthomorpha enghoffi sp. n., holotype (A & B), O. subsericata Golovatch, 1997, male from Kholong Wan (C & D), and O. alutaria sp. n., male paratype from Khao Wong Phrachan Temple (E & F). A – F: right gonopod, mesal, lateral, mesal, lateral, mesal and lateral views, respectively. Scale bar: 0.5 mm.

FIGURE 7. Orthomorpha alutaria sp. n., female paratype from Tham Khao Wong Temple (A) and male paratype from Khao Wong Phrachan Temple (B – J). A: habitus, live coloration. B & C: anterior part of body, dorsal and lateral views, respectively. D & E: segments 10 and 11, dorsal and lateral views, respectively. F – H: posterior part of body, dorsal, ventral and lateral views, respectively. I & J: sternal lamina between coxae 4, subcaudal and sublateral views, respectively.