Oocyclus viridescens 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 : 21-23

Oocyclus viridescens Short & Swanson , sp. n.

( Figs. 5 , 13 )

Type Locality. Thailand: Chiang Mai Province, Doi Inthanon National Park, 18°31N, 98°27E, 1060 m.

Type Material. Holotype: Male. “ THAILAND: Chiang Mai Prov. / Doi Inthanon Nat. Park, 1060 m / NT Huai Sai Leung 20–31.iii.2002, 18°31N, 98°27E, G.W. Courtney, BLT ”, “ HOLOTYPE / Oocyclus / viridescens / Short & Swanson” ( USNM). Paratypes (47). THAILAND: Chinag Mai Province: Doi Suthep­Pui National Park, Namtok Huay Pa Lad, rock face, 1250 m, 29.iv.2003, AV, Thamasenanupap & Ferro leg., L­488 (8: AEZS, UMRM); same locality but 5.iii.2002, L­264 (3: UMRM); Doi Suthep­Pui National Park, Namtok Monthathan, 700 m, 29.iv.2003, AV, Thamasenanupap & Ferro leg., L­489 (3: UMRM); same locality but immediately below falls, 5.iii.2003, L­296 (1: UMRM). Mae Hong Son Province: Tham Pla­Pha Seu National Park, Phae Seu Waterfall, 415 m, 1.iv.2003, UMC & CMU teams, L­432 (1: UMRM). Phitsanuiok Province: Phu Hin Rongkla National Park, Namtok Romglao, 1190 m , various dates and collectors from 11.iii.2003 to 6.v.2003 (27: AEZS, BMNH, CUIC, EMBT, ISU, NMW, UMRM, USNM); Phu Hin Rongkla National Park, Huai Kha Mhuen Waterfall, rock pool, 1253 m, 6.v.2003, Vitheepradit, Prommi & Ferro leg., L­505 (1: UMRM). Uttaradit Province: Klong Tron National Park, Klong Tron Waterfall, 662 m, rock face, 26.iv.2003, AV, Prommi, & Setaphan leg., L­486 (3: UMRM).

Diagnosis. Posterolateral corners of pronotum evenly rounded ( Fig. 13 ). Labrum with row of systematic punctures very dense, nearly forming a median grove. Procoxae without distinct spines. Most similar to O. sitesi but with setiferous punctures on elytra blending with general punctuation, which is composed of different sized punctures.

Description. Size and Form. Length= 3.3–3.7 mm. EL/EW= 1.08 mm. Oval, strongly convex. Elytra slightly longer than wide. Color. Dorsum black. Head, pronotum and often elytra with a green sheen. Maxillary and labial palpi yellow. Mentum and stipes light to reddish brown, distinctly paler than ventral face of head. Legs, epipleura, lateral margins of prosternum and posterior half of each ventrite yellow to light brown, with remainder of venter slightly to moderately darker reddish brown. Head. General punctation on labrum, clypeus and frons slightly variable in size from almost undetectable to fine; fairly densely distributed, distance between punctures 0.1–1.5x the width of one puncture. Systematic row of punctures on the labrum very dense, more or less forming a lateral, shallow median groove, and set with a dense row of long erect yellow setae. Frons with an irregular row of systematic punctures mesad of each eye, bearing fine erect setae. Clypeus with a few very indistinct systematic punctures along anterolateral margins, slightly larger than surrounding punctation and usually bearing short setae. Antennae with scape subequal in length to segments 2–5; first two segments of club subequal in length, and apical segment slightly longer than two preceding segments combined.. Maxillary palpi very short, slightly shorter than the width of labrum; segment 2 slightly bulbous, apical segment slightly longer than penultimate. Labial palpi three­fourths as long as width of mentum. Mentum quadrate, anterior margin slightly convex; bearing very fine and scattered punctures, some of which bear fine, long setae. Thorax. General punctation on pronotum and elytra composed of extremely fine and moderately coarse punctures, evenly mixed and distributed. Pronotal systematic punctures present, but sometimes partially blending with larger general punctures, usually 1.5–2.0x the size of general punctation and set with a fine recumbent seta; anterior and posterior series each forming an irregular row. Lateral margins of pronotum set with a few sparsely distributed setiferous punctures; appearing absent in some specimens. Posterolateral corners of pronotum evenly rounded ( Fig. 13 ). Sutural punctation on elytra absent or unmodified from general punctation. Elytra without distinct rows of larger punctures, as they blend uniformly with general punctation; these rows (of systematic punctures) can be detected in some specimens by the presence of a fine, short seta. Prosternum with median carina along entire length, with an acute tooth anteriorly; without long spines or hairs anteriorly. Mesosternal process with lateral extensions sloping evenly downward; apex set with a few long fine setae. Metasternum with small oval glabrous area posteromedially, slightly longer than wide, length of glabrous area about one­third the total length of the metasternum. Pro­ and mesocoxae densely pubescent; without spines. Protibiae with 10–12 spines on dorsal face. Protarsal segments 1–4 small, subequal in length, apical segment ca. as long as segments 1–4 combined. Abdomen. Ventrites 1–4 with two lateral rows of very long, fine setae; longest setae longer than the setae around the metasternal glabrous area. Fifth ventrite entire; with dense, uniform setae over entire surface. Aedeagus ( Fig. 1 ) with inner and outer margins of parameres nearly straight; apex of parameres evenly rounded. Apex of median lobe with dorsal strut slightly but distinctly arising above gonopore. Dorsal face of median lobe with an oval depression basally.

Distribution. Thailand.

Etymology. Named for the subtle green iridescence on the dorsum of most specimens.

Remarks. See remarks under O. bhutanticus . Prior Thai records of that species may refer to O. viridescens .

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.