Orthomorpha subsericata Golovatch, 1997

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 : 30-31

Orthomorpha subsericata Golovatch, 1997

Figs 3 C & D, 5 & 6.

Orthomorpha subsericata Golovatch, 1997: 35 . Orthomorpha subsericata: Enghoff, 2005: 98 .

Material examined: Holotype male, paratype female ( ZMUC), Thailand, Hua Hin, West coast of Siam Gulf, 6–7 September 1981, leg. R. Nielsen. Additional records: 3 males, 2 females, 1 juvenile ( CUMZ), Thailand, Prachuap Khiri Khan Province, Mueang Prachuap Khiri Khan District, Kholong Wan, 8 August 2009. leg. I. Siraipram. 12 males, 9 females, 1 juvenile ( CUMZ), same Province, Bang Saphan Distinct, Proud Thai Beach Resort, 11°21´7˝N, 99°34´2˝E, 8 October 2008, leg. N. Likhitrakarn and members of Animal Systematics Research Unit.

Diagnosis: Differs from congeners in the shining metaterga, coupled with the black-and-red live colour pattern, and the tip of the solenophore like a single, slightly undulate, elongate lobe.

Description: Length 16.5–17.8 mm (male), 18.5–22.3 mm (female), width of midbody pro- and metazona 1.4–1.9 and 2.3–2.8 mm (male), 1.9–2.2 and 2.7–3.2 mm (female), respectively. Live coloration ( Fig. 5 A) blackish, head and antennae black, paraterga and epiproct contrastingly red, legs brownish; coloration in alcohol faded to dark brown, pale pinkish or pale brown, respectively, after one year of preservation.

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

Vertigial part sparsely setose. Head in width <collum <segments 3 and 4 <2=5–16 (male), body gradually tapering thereafter. Collum with 3rd row of setae not borne on knobs; paraterga like small, caudally nearly pointed, subrectangular, declined flaps ( Figs 5 B & C).

Tegument smooth and shining ( Figs 5 B–H), prozona and surface below paraterga finely shagreened, that below paraterga often delicately rugulose as well; metaterga smooth and shining, only at places finely striolate/rugulose. Metaterga with two transverse rows of setae not borne on knobs, pattern traceable 2+ 2 in front of and 2(3)+2(3) behind sulcus, most of setae being abraded. Axial line usually traceable on metaterga. Paraterga very strongly developed ( Figs 5 B–H), set high, but remaining below dorsum even in male, usually subhorizontal, caudal tip almost completely to fully pointed. Paraterga 2 with three, all subsequent poreless paraterga with two evident, but less strongly developed incisions laterally ( Fig. 5 B). Paraterga 2–16 with anterior edge slightly convex and then straight, directed more laterally on segments 17 and 18, spiniform and directed caudad on segment 19. All postcollum paraterga at least slightly surpassing rear contour, caudal edge evidently concave, narrowly bordered, unfringed, lacking lobe ( Fig. 5 D). Stricture between pro- and metazona deep, narrow, roughly beaded/ribbed down to slightly below paraterga ( Figs 5 B, D, E–H). Transverse sulcus incomplete on metatergum 4, evident, fully developed and reaching bases of paraterga on segments 5–18, slightly arcuate and clearly beaded ( Figs 5 B–H). Pleurosternal carinae well-developed as distinct caudal tooth on segments 2–7 (male) ( Fig. 5 C), as indistinct tooth on segment 8, traceable as arcuate swelling until segment 13 (male) or present as caudal tooth on segments 2–4, nearly absent from segment 5 (female), entirely absent thereafter. Epiproct ( Figs 5 F & G) with smaller apical and slightly larger preapical papillae. Sterna shining, sparsely setose, lobe between male coxae 4 single, but medially notched ( Figs 5 I & J). Ridge in front of gonopod aperture lower, not as prominent as in O. enghoffi sp. n. Legs shorter, about 1.2 (male) or 1.0 times (female) as long as midbody height.

Gonopods ( Figs 3 C & D, 6) with tip of solenophore like a single, slightly undulate, elongate lobe.

Remarks. This species has hitherto been known only from the male holotype and a female paratype ( Golovatch, 1997). The above refined redescription is given to provide additional information viz-a-viz the other congeners, being based both on type and a considerably more abundant fresh material. This species was found at dawn in the soil off a strand when the animals came up to the surface.

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 5. Orthomorpha subsericata Golovatch, 1997, male from Kholong Wan. 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.