Oocyclus thailensis Short & Swanson

Short, A. E. Z. & Swanson, A. P., 2005, A revision of the Oocyclus Sharp of Thailand with description of six new species (Coleoptera: Hydrophilidae), Zootaxa 1078, pp. 1-24 : 19-21

Oocyclus thailensis Short & Swanson , sp. n.

( Figs. 4 , 15 )

Type Locality. Thailand: Phitsanulok Province, Phu Hin, Rongkla National Park, Namtok Romglao, Romglao Waterfall, 16°59N, 101°00E, 1190 m.

Type Material. Holotype: Male. “ THAILAND: Phitsanulok Pro. Phu Hin / Rongkla Natl. Pk. Namtok Romglao / 1190 m L­507, 16°59N101°00E / 6­V­2003, CMU Team”, “ HOLOTYPE / Oocyclus / thailensis / Short & Swanson” ( USNM). Paratypes (162): THAILAND: Chiang Mai Province: Doi Suthep National Park, Namtok Monthathan, 700 m, various dates and collectors (16: UMRM); same locality but “below falls”, 690 m, 5.iii.2002, R. Sites leg., L­296 (8: UMRM); Doi Suthep National Park, Huay Sai Lueung waterfall, 1060 m, 20.iii.2002, R. Sites leg., L­311 (1: UMRM). Kampaeng Phet Province: Klong Lan National Park, Namtok Klong Lan waterfall/ rock face, 310 m, various dates and collectors from 8.iii.2002 to 7.iv.2003 (32: AEZS, ISU, UMRM, USNM). Loei Province: Na Haew National Park, Wahng Tahd Waterfall rock face, 977 m, various dates and collectors (7: AEZS, UMRM); Phu Rua National Park, Namtok Hin Sahm Shan, waterfall, 10.vi.1998, Sites, Simpson & Vitheepradit leg., L­176 (5: UMRM). Phitsanuiok Province: Same data as holotype (60: AEZS, BMNH, CUIC, ISU, MCZ, NMW, USNM, EMBT, UMRM); same locality but various other dates and collectors (31: AEZS, UMRM, USMN); Phu Hin Rongkla National Park, Waterwheel falls, big pool, 1280 m, 21.iv.2002, N. Changthong leg. (1: UMRM); Phu Hin Rongkla National Park, Hua Kha Mhuen Waterfall rock face, 1253 m, 6.v.2003, Vitheepradit, Prommi & Ferro leg., L­505 (1: UMRM).

Diagnosis. Posterolateral corners of pronotum weakly spinose ( Fig. 15 ). Procoxae covered with coarse spines. Ventrites not uniformly pale in coloration. Most similar to O. namtok but larger in size.

Description. Size and Form. Length= 4.7–5.1 mm. EL/EW=1.07. Broadly to slightly elongate oval, moderately convex. Elytra longer than wide. Color. Dorsum black. Head and pronotum with faint mottled green iridescence; sometimes also present on elytra. Maxillary and labial palpi uniformly yellow; some specimens with apex of apical maxillary palpomere slightly darkened. Mentum and stipes reddish brown, paler than ventral face of head. Lateral margins of prosternum, mesosternum, pseudoepipleura, and legs reddish brown, slightly paler than center of prosternum and metasternum. Posterior margins of ventrites light brown to orange, with anterior halves dark brown. Head. General punctation on labrum, clypeus and frons composed of multiple size punctures, from almost undetectable to fine; distance between punctures 0.5–1.0 the width of one puncture. Systematic punctures on labrum composed of a median row of coarse punctures bearing fine, long erect setae, distance between punctures 0.5–1.0x width of one puncture. Frons with an irregular row of systematic punctures mesad of each eye, bearing fine recumbent to erect setae. Clypeus with a few very indistinct systematic punctures along anterolateral margin; almost undetectable; slightly larger than surrounding punctation and usually bearing a short seta. Antennae with scape subequal in length to segments 2–5; first two segments of club subequal in length and apical segment slightly shorter than two preceding segments combined. Maxillary palpi short, subequal in length to the width of labrum; apical segment 1.5x as long as penultimate. Labial palpi threefourths as long as width of mentum. Mentum quadrate, anterior margin slightly convex; bearing nearly obsolete scattered punctures, some of which bear fine setae. Thorax. General punctation of pronotum and elytra moderately fine but always distinct; punctures of various sizes. Pronotal punctation pattern similar but slightly less impressed. Pronotal systematic punctures distinct, each bearing a short recumbent seta; anterior series each forming an irregular row; posterior series more diffused into a short field. Lateral margins of pronotum with a few sparse setiferous punctures. Posterolateral corners of pronotum weakly but distinctly spinose ( Fig. 15 ). Sutural punctation on elytra unmodified from general punctation. Elytra with five diffuse rows of very coarse setiferous punctures: rows 1–3 with punctures spaced irregularly but linearly, bearing recumbent to erect setae; row 4 more or less a field of irregularly spaced punctures with recumbent to erect setae; row 5 extremely close to lateral margin, bearing erect fine setae. Prosternum with median carina along entire length, with a small acute tooth anteriorly; without long spines or hairs anteriorly. Mesosternal process with lateral extensions sloping evenly downward; apex set with a few fine setae. Metasternum with small oval glabrous area posteromedially, ca. twice as long as wide, length of glabrous area about half the total length of metasternum. Procoxae covered with short, coarse spines; most specimens with mesocoxae set with 2–4 short spines or thickened, coarse setae. Protibiae with 8–13 spines on dorsal face. Protarsal segments 1–4 small, subequal in length, and apical segment ca. as long as segments 1–4 combined. Abdomen. Ventrites with moderately dense pubescence, with longest setae shorter to subequal in length to longest setae around mesosternal glabrous area. Fifth ventrite entire, with pubescence slightly denser than ventrites 1–4. Aedeagus ( Fig. 4 ) with outer margin of parameres arcuate, with apex of parameres broad; median lobe appearing triangular.

Distribution. Thailand.

Etymology. Named after the country from which it is described.

Figures

FIGURES 1 – 6. Oocyclus aedeagi, dorsal views. 1. O. viridescens sp. n. 2. O. sitesi sp. n. (holotype). 3. O. namtok sp. n. 4. O. thailensis sp. n. (holotype). 5. O. sumatrensis d’Orchymont (specimen from Thailand). 6. O. melinoventris sp. n. Scale Bar = 0.18 mm.

FIGURES 11 – 15. Details of Oocyclus. 11 – 12. Thoracic sterna. 11. O. melinoventris sp. n. (holotype). 12. O. sitesi sp. n. (holotype). 13 – 15. Lateral margin of pronotum, with posterolateral corner to the right. 13. O. viridescens sp. n. 14. O. sumatrensis d’Orchymont. 15. O. thailensis sp. n. Scale bar = 1 mm.