Oocyclus melinoventris 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 : 8-12

Oocyclus melinoventris Short & Swanson , sp. n.

( Figs. 6–8 , 11 )

Type Locality. Thailand: Chiang Mai Province, Doi Suthep National Park, Monthanthan waterfall, 18°49N 98°55E.

Type Material. Holotype: Male. “ THAILAND: Chiang Mai Prv. Doi / Suthep Natl. Pk. Nam Tok Monthanthan / 700 m L­330 18°49N 98°55E 8.IV.2002 / UMC & CMU Teams”, “ HOLOTYPE / Oocyclus / melinoventris / Short & Swanson” ( USNM). Paratypes (50): THAILAND: Chiang Mai Province: Doi Suthep­Pui National Park, Namtok Monthathan, 700 m, 29.iv.2003, Thamasenanupap and Ferro leg., L­489 (5: AEZS, UMRM); same data as holotype 19: AEZS, USNM, UMRM); same locality but 29.iii.2003, UMC & CMU teams, L­427 (2: UMRM); Doi Suthep­Pui National Park, immediately below Monthathan falls, 690 m, 5.iii.2002, R. W. Sites leg., L­296 (12: UMRM); Doi Inthanon National Park, Sob Ab Waterfall, 600 m, 2.v.2003, UMC & CMU teams, L­495 (1: AEZS). Kampaeng Phet Province: Khlong Lan National Park, Khlong Lan Waterfall, 310 m, 6.iv.2003, Sites, AV, Prommi, Setaphan leg., L­449 (6: AEZS, UMRM); same locality but 8.iii.2002, R. Sites leg., L­273 (1: UMRM). Loei Province: Na Haew National Park, Wahng Tahd Waterfall, rock face, 977 m, 25.iv.2003, AV, Prommi & Setaphan leg., L­484 (3: AEZS, USMN, UMRM). Surathani Province: Kang Krung National Park, Bang Jam Waterfall, rock pool, 159m, 25.v.2003, Vitheepradit, Laudes, & Ferro leg., L­568 (1: USNM). Representative material deposited in BMNH, CUIC, EMBT, ISU, MCZ, & NMW.

Diagnosis. Posterolateral corners of pronotum angulate but not spinose. Procoxae covered with coarse spines. Ventrites uniformly pale in coloration. Glabrous area of mesosternum extending entire length, which distinguishes this species from all others in Thailand.

Description. Size and Form. Length=4.2–5.0 mm. EL/EW=1.05. Broadly oval, moderately convex. Elytra slightly longer than wide. Color. Dorsum black. Head and pronotum with distinct green iridescence; rarely detectable on elytra. Maxillary palpi yellow except apex of the apical segment, which is slightly darkened; labial palpi yellow. Mentum and stipes dark brown to black, the same color as ventral face of head. Legs, pseudoepipleura and lateral margins of prosternum reddish brown, with the remainder of the sternum dark brown to black. Ventrites uniformly light to reddish brown, distinctly paler than the sternum. Head. General punctation on labrum, clypeus and frons slightly variable in size from almost very fine to moderately fine; dense, distance between punctures 0.5–1.0x the width of one puncture. Systematic row of punctures on labrum composed of coarse, setiferous punctures laterally with center half of row appearing absent or with punctures reduced in size as to blend with general punctation. 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 margins, 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, slightly longer in length than 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 distinct scattered punctures, some of which bear fine setae. Thorax. General punctation on elytra dense, distance between punctures 0.5–1.0x the width of one puncture, composed of punctures of varying size, from very fine to moderately coarse; becoming extremely dense posteriorly, making elytra appear almost rugose. Pronotal punctation similar but distinctly less impressed. Pronotal systematic punctures distinct, 1.5– 2 x the size of larger general punctation punctures and set with a fine recumbent seta; anterior and posterior series each forming an irregular row. Lateral margins of pronotum with a sparse row of setiferous punctures. Posterolateral corners of pronotum angulate, but not spinose. Sutural punctation on elytra unmodified from general punctation. Elytra with five diffuse rows of setiferous punctures, which are sometimes partially obscured by the larger general punctures, but always detectable: rows 1–3 with punctures spaced irregularly but linearly, bearing recumbent setae; row 4 more or less a field of irregularly spaced punctures with recumbent to erect setae; row 5 along extreme lateral margin, bearing erect fine setae. Prosternum with fine median carina along entire length, without a tooth anteriorly or long setae anteriorly. Mesosternal process with lateral extensions sloping evenly downward; apex set with a few fine setae. Metasternum with glabrous area extending to entire length, slightly narrower than width of mesosternal process anteriorly, becoming evenly narrowed anteriorly. Procoxae covered with short spines and coarse long setae; mesocoxae without spines, at most with a few coarse, long setae. Protibiae with 10–13 spines on dorsal face. Protarsal segments 1–4 small, subequal in length; apical segment ca. as long as segments 1–4 combined. Abdomen. Ventrites with moderately dense pubescence, the 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. 6 ) with parameres moderately wide basally, with apex distinctly narrowed on both outer and inner margins. Median lobe parallel­sided and moderately narrow.

Distribution. Thailand.

Etymology. The species name, melinoventris , refers to the pale orange color of the ventrites.

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.

FIGURE 7. Oocyclus melinoventris sp. n. (holotype). Dorsal and lateral habitus. Scale bar = 2 mm.

FIGURE 8. Oocyclus melinoventris sp. n. (holotype). Ventral habitus. Scale bar = 2 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.