Cryptocorypha enghoffi, Likhitrakarn, Natdanai, I. Golovatch, Sergei, Srisonchai, Ruttapon, Chirasak Sutcharit, & Panha, Somsak, 2019

Likhitrakarn, Natdanai, I. Golovatch, Sergei, Srisonchai, Ruttapon, Chirasak Sutcharit, & Panha, Somsak, 2019, A new species of the millipede genus Cryptocorypha Attems, 1907, from northern Thailand (Polydesmida, Pyrgodesmidae), ZooKeys 833, pp. 121-132 : 121

Cryptocorypha enghoffi sp. n. Figs 1, 2, 3, 4

Holotype.

♂ (CUMZ), Thailand, Chiang Mai Province, Doi Saket District, Huai Hong Khrai Royal Development Study Centre, 445 m a.s.l., 18°52'47"N, 99°13'22"E, 06/05/2015, leg. N. Likhitrakarn. Paratypes. 2 ♂, 3 ♀, 1 subadult (19 segments), 1 juvenile (18 segments) (CUMZ), 1 ♂, 1 ♀ (ZMUM), same locality, together with holotype. 1 ♂, 1 ♀, 2 subadult (19 segments) (CUMZ), 1 ♂, 1 ♀ (ZMUC), 1 ♂, 1 ♀ (NHMW), 1 ♂, 1 ♀ (NHML), same locality, 09/06/2016, leg. N. Likhitrakarn.

Name.

Honours Henrik Enghoff, a globally renowned specialist in Diplopoda and one of the pioneers of diplopodological research in Thailand.

Diagnosis.

Differs from other species of the genus by the presence of 20 body segments in both sexes, coupled with an evident apicodorsal trichostele on the last tibia of both sexes (Fig. 4F) and in the gonopod structure being particularly complex, similar to that of C. perplexa Golovatch & VandenSpiegel, 2015, but differs clearly in the shapes and armament of all four main outgrowths of the telopodite (Fig. 4 A–D).

Description.

Length ca. 12.1 mm, width of midbody segments 2.95 and 1.55 mm on pro- and metazonae, respectively (holotype). Length of adults ca. 11.5-12.8 mm (♂ paratypes) and 14.5-15.2 mm (♀ paratypes), width of midbody pro- and metazonae 0.8-1.2 and 2.2-2.6 mm (♂ paratypes) or 1.2-1.8 and 2.8-3.4 mm (♀ paratypes), respectively.

Coloration of live animals uniformly reddish to purplish red (Fig. 1A, B), antennae, legs, and venter mainly lighter, yellowish to reddish (Fig. 1A); coloration in alcohol, after three years of preservation, faded to reddish (Fig. 1 C–E) or light brown, antennae and legs light red to light brown, while venter yellowish to nearly pallid (Fig. 1D, E).

Body robust, with 20 segments (♂, ♀). Pro- to metazonum width ratio close to 1:2. In width, head << collum <segment 3 = 4 <2 <5 <6-14(15) (♂, ♀), thereafter body rapidly tapering towards telson (Figs 1C, D, 3G, H). Head subovoid (Fig. 2B, C, E), slightly transverse, densely setose in clypeolabral region, micropapillate; epicranial suture superficial. Interantennal isthmus approximately twice as large as either diameter of antennal socket or antennomere 1 (Fig. 2B, E).

Antennae short and clavate (Figs 1A, D, 2B, C, E, G), in situ reaching body segment 3 (♂, ♀) when stretched laterally or ventrolaterally; in length, antennomere 1 <2 <4 <7 <3 <5 <6; antennomeres 5-7 each with a more or less compact apicodorsal group of bacilliform sensilla (Fig. 2 G–K).

Collum flabellate (Figs 1A, C, 2 A–E), completely covering the head from above, anterior margin regularly rounded, with 11 equal, long and evident radii (Figs 1C, 2A); middle and caudal parts with two transverse, arched, rather faint rows of low bosses (Figs 1C, 2A, C, D). Paraterga set at approximately upper 1/3 (♂, ♀) of body height, subhorizontal to faintly declivous (♂, ♀) (Figs 1E, 2C). Dorsum moderately convex, its outline smoothly extending onto paraterga (Fig. 2C).

Tegument encrusted with a microspiculate cerotegument, dull, beset with microvilli (Figs 2A, C, D, F, 3A, C–G, I, J). Prozonae and strictures between pro- and metazonae very delicately microgranulate, also beset with microvilli (Fig. 3F), conforming to the pattern observed in C. ornata and several other genera and species of Pyrgodesmidae (cf. Akkari and Enghoff 2011). Metaterga with three transverse rows of non-differentiated tuberculations and distinct rows of usually transversely oblong, polygonal to rounded, low bosses (Figs 2A, 3A, J), except for collum and segments 2-4 showing two transverse rows of such tuberculations (Fig. 2A, D), each of the latter typically surmounted by minute, setigerous, spherical knobs (Fig. 3D). Paraterga areolate-rugose, beset with microvilli arranged in a polygonal alveolate pattern (Fig. 3E; see also Akkari and Enghoff 2011 for comparison). Tergal setae mostly abraded, retained ones inconspicuous and very short.

Postcollum paraterga very broad, thin and slightly, but clearly lobulate laterally (Figs 1A, C, 2A, B, 3A, B, D, G, H, J), with three lobulations in all poreless segments, four lobulations in all pore-bearing ones, all also delimited by very long, rather evident radii both dorsally and ventrally; anterior marginals absent, but two caudal marginals evident.

Pore formula normal: 5, 7, 9, 10, 12, 13, 15-19, ozopores being very small, round, discernible dorsally at base of 3rd lobulation (Figs 2A, F, 3A, D, E, G, J).

Limbus microspiculate, each caudal crenulation being very finely and sharply spinulose (Fig. 3F).

Epiproct readily visible from above, not hidden under 19th segment (Figs 1A, 3G, J), with four strong setae on top (Fig. 3K).

Hypoproct subtriangular, caudal edge with 1+1 strong and widely separated setae on evident knobs (Fig. 3K).

Sterna wide, approximately twice as broad as diameter of coxal socket (Figs 1D, 2B, 3B, H, K), moderately setose, without modifications, superficially impressed along main axis. Epigynal ridge behind ♀ legs 2 low and inconspicuous. Gonopod aperture transversely oblong-oval, caudal and lateral margins thin and slightly elevated.

Legs long and slender (Fig. 4E), longer than width of paraterga, densely setose, last tibiae with evident apicodorsal trichosteles in both sexes (Figs 3I, K, L, 4F); in length, tarsi> femora> prefemora >> tibiae> coxae> postfemora (♂, ♀), neither adenostyles nor tarsal brushes. Claws simple, slightly curved ventrad.

Gonopods (Fig. 4 A–D) very complex, in situ held parallel to each other; coxite rather small, boat-shaped, gonocoel shallow, cannula simple. Each telopodite grossly quadripartite: (1) an evident, long, suberect, rod-shaped, apically unequally bifid and acuminate endomere tightly appressed to and starting at base of (2) the longest, suberect, rod-shaped, distally curved, apically conspicuously and densely fringed/fimbriate solenomere, followed first (3) by a sac-shaped, mesally irregularly membranous, low velum and then (4) by a conspicuous, long, clearly papillate/dentate, strongly curved, apically slightly clavate and rounded exomere.

Remarks.

This new species was found walking on a rock surface (Fig. 1B). The air was very humid, this being characteristic of the rainy season. The specimens were found in the Dry Dipterocarp Forest at the Huai Hong Khrai Royal Development Study Centre. This study centre was established under the royal initiative in 1982 in the area of Khun Mae Kuang National Forest Reserve, Chiang Mai Province for conducting research and experimentation using appropriate progressive methods which suited the development needs of the Northern Region, especially the conservation of watersheds, reforestation and agricultural development. It covers approximately 8,500 rai (1,360 hectares).