Oocyclus Sharp

Short, Andrew Edward Z. & Jia, Feng-Long, 2011, Two new species of Oocyclus Sharp from China with a revised key to the genus for mainland Southeast Asia (Coleoptera: Hydrophilidae), Zootaxa 3012, pp. 64-68 : 67-68

Key to the species of Oocyclus Sharp from mainland Southeast Asia

This key is modified from Short & Swanson (2005), and incorporates the changes made by Minoshima (2009). We also have included the species recently described from eastern India by Short (2009). Additional figures to help with character understanding are can be found in those three references and are not repeated here.

1 Procoxae pubescent, without distinct spines. Posterolateral corners of pronotum evenly rounded or angulate. Abdominal ventrites evenly and finely pubescent or each with two rows of long hairs. Size usually less than 4.0 mm (except O. bhutanicus )..................................................................................................... 2

- Procoxae covered with short, coarse distinct spines (spines present but indistinct in O. rupicola Minoshima, 2009 and O. arm-

strongorum Short, 2009). Posterolateral corners of pronotum angulate or spinose. Abdominal ventrites evenly covered with fine pubescence. Size usually larger than 4.0 mm (except some O. sumatrensis ).................................... 7 2 Abdominal ventrites 1-4 with two or three irregular rows of long hairs............................................ 4

- Abdominal ventrites 1-4 covered with fine, dense pubescence.................................................. 3

3 Elytra ground punctation of mixed sizes, with smallest punctures larger in comparison. Anterior tooth of prosternal carina slightly smaller in comparison. Metafemora ca. 2.3 times as long as wide..................... O. bhutanicus Satô, 1979

- Elytra ground punctation of mixed sizes, with smallest punctures smaller in comparison. Anterior tooth of prosternal carina slightly larger in comparison. Metafemora ca. 2.1 times as long as wide......................... O. madidus Short, 2009

4 Elytra without distinct rows of systematic punctures; setiferous punctures present but almost indistinguishable from coarse general punctation..................................................................................... 5

- Elytra with five distinct rows of setiferous punctures; general punctation fine............. O. sitesi Short & Swanson, 2005

5 Aedeagus with apical half of parameres straight. Metafemora with fine microreticulation on ventral surface..................................................................................... O. viridescens Short & Swanson, 2005

- Aedeagus with apical half of parameres straight or inwardly curved. Metafemora without fine microreticulation on ventral surface................................................................................................ 6

6 Apex of apical maxillary palpomere darkened. Aedeagus as in Fig. 2 A; parameres only slightly expanded at apex, or appearing not expanded; gonopore further from the apex of the median lobe......................... O. fikaceki Short & Jia sp.n.

- Apex of apical maxillary palpomere not darkened, entire palp uniform in color. Aedeagus as in Fig. 2 B, parameres distinctly expanded in apical third compared with middle third; with gonopore closer to the apex of the median lobe.............................................................................................. O. dinghu Short & Jia sp. n.

7 Central metaventral glabrous area extending to the entire length of the metaventrite. Posterolateral corners of pronotum angulate but not spinose.................................................................................... 8

- Central metaventral glabrous area not extending the entire length of the metaventrite (ca. one-third to two-thirds). Abdominal ventrites variously colored. Posterolateral corners of pronotum angulate or spinose.................................. 9

8 Abdominal ventrites uniformly pale, distinctly paler than sternum............... O. melinoventris Short & Swanson, 2005

- Abdominal ventrites dark brown to black........................................... O. armstrongorum Short, 2009

9 Posterolateral corners of pronotum slightly prolonged, spinose................................................. 11

- Posterolateral corners of pronotum angulate................................................................ 10

10 Size small (3.7–4.3 mm). Spines on procoxae coarse and distinct. Ground punctation on elytra fine............................................................................................... O. sumatrensis d’Orchymont, 1932

- Size large (4.9–5.6 mm). Spines of procoxae thin, sparse and indistinct, more resembling thickened, stiff setae. Ground punctation of elytra very coarse......................................................... O. rupicola Minoshima, 2009

11 Abdominal ventrites uniformly pale. General punctation of elytra coarse................ O. foxae Short & Swanson, 2005

- Abdominal ventrites variously colored, but never uniformly pale. General punctation of elytra not as coarse............. 12

12 Size 4.7–5.1 mm. Parameres only slightly tapered, more broadly rounded at tip. General punctation of elytra slightly more coarse.................................................................. O. thailensis Short & Swanson, 2005

- Size 4.0– 4.5 mm. Parameres evenly tapered to a narrow, blunt tip. General punctation of elytra more fine.......................................................................................... O. namtok Short & Swanson, 2005

Figures

FIGURE 2. Dorsal view of the aedeagus of Oocyclus spp., A) O. fikaceki sp. n., paratype, B) O. dinghu sp. n., holotype (scale bar = 0.25 mm).