Oocyclus thailensis Short et Swanson, 2005

Minoshima, Yûsuke, 2009, First record of the hygropetric genus Oocyclus Sharp (Coleoptera: Hydrophilidae) from Laos, with description of a new species, Zootaxa 2192, pp. 45-55 : 52-54

Oocyclus thailensis Short et Swanson, 2005

( Figs. 4 , 5 )

Oocyclus thailensis Short et Swanson, 2005: 19 (original description); Short & Hebauer, 2006: 326 (corrections and additions of catalogue).

Type locality. Thailand: Phitsanulok Province, Phu Hin, Rongkla National Park, Namtok Romglao, Romglao Waterfall, 16°59N, 101°00E, 1190 m ( Short & Swanson, 2005).

Material examined. 35 males, 19 females, and 22 exs., Route 8, 11 km Southwest by South of Ban Pakha, Bolikhamxai prov., Laos, 18°11.83´N, 104°36.19´E, 25. V. 2008, Y. Minoshima leg., MiYu-L-08-039 ( EUMJ, KSEM, SEHU, MYC).

Additional description. Female. Body size slightly larger than male (see measurements); otherwise almost identical to male. Spermathecal organ ( Fig. 5 D). Spermathecal duct long (278–313 (294 ± 12) μm; n=6), distinctly longer than duct of the spermathecal gland, slightly slender; infundibulum undetectable; spermatheca rather large, oval; cornu undetectable; duct of the spermathecal gland short (63–86 (73 ± 8) μm; n=6), weakly swollen, slender at base; spermathecal gland slender, long.

Measurements. Male (n=10): TL: 4.35–4.80 (4.63 ± 0.15) mm; HW: 1.43–1.58 (1.51 ± 0.05) mm; ED: 0.90–0.95 (0.92 ± 0.02) mm; PL: 1.05–1.20 (1.10 ± 0.04) mm; PW: 2.73–3.05 (2.90 ± 0.10) mm; EL: 3.25– 3.70 (3.53 ± 0.14) mm; EW: 3.00–3.40 (3.24 ± 0.13) mm; ED/HW: 0.59–0.63 (0.61 ± 0.02); PW/PL: 2.48– 2.81 (2.63 ± 0.09); EL/EW: 1.04–1.18 (1.09 ± 0.04). Female (n=10): TL: 4.63–5.20 (4.92 ± 0.18) mm; HW: 1.45–1.65 (1.57 ± 0.05) mm; ED: 0.93–1.03 (0.99 ± 0.03) mm; PL: 1.05–1.25 (1.17 ± 0.05) mm; PW: 2.80– 3.20 (3.06 ± 0.11) mm; EL: 3.58–4.03 (3.75 ± 0.14) mm; EW: 3.13–3.50 (3.39 ± 0.12) mm; ED/HW: 0.59– 0.65 (0.63 ± 0.01); PW/PL: 2.56–2.69 (2.62 ± 0.04); EL/EW: 1.06–1.15 (1.11 ± 0.03).

Distribution. Thailand, new to Laos.

Biology. Found together with the newly described species ( Fig. 6 ).

Remarks. This species is found together with O. rupicola on the same rock surface in Laos; however, in Thailand, this species is collected with O. melinoventris Short et Swanson, 2005 , O. viridescens Short et Swanson, 2005 , or both in some localities ( Short & Swanson, 2005).

Figures

FIGURE 4. SEM photographs of O. thailensis Short et Swanson: A: Habitus, dorsal view; B: ditto, ventral view; C: posterolateral corner of pronotum, dorsal view; D: punctation of elytra; E: head, ventral view; F: prosternum and mesoventrite, ventral view. [A, C – D: male, MiYu-D- 00136; B, E – F: male, MiYu-D- 00138]

FIGURE 5. Oocyclus thailensis Short et Swanson: A: Aedeagus, dorsal view; B: 9 th sternite, dorsal view; C: 9 th tergite, ventral view; D: spermathecal organ. [A – C: male, MiYu-D- 00101, D: female, MiYu-D- 00126]

FIGURE 6. A: Type locality and habitat of O. rupicola sp. n., and collecting locality of O. thailensis Short et Swanson, Laos: Route 8, 11 km Southwest by South of Ban Pakha, Bolikhamxai Province, 25 May 2008; B, C: Oocyclus species, same data as Fig. 6 A. Photographs by the author.