Ilybiosoma yeti Brancucci & Hendrich

Brancucci, Michel & Hendrich, Lars, 2008, 5100 m above sea level: Agabus joachimschmidti sp. n. and notes on other high altitude diving beetles from Tibet and Bhutan (Coleoptera, Dytiscidae), Zootaxa 1825, pp. 51-58 : 55-57

Ilybiosoma yeti Brancucci & Hendrich

Figs 6 & 7

Ilybiosoma yeti Brancucci & Hendrich, 2006 : Brancucci & Hendrich (2006).

Material studied. 12 males, 3 females: “Tibet South Central, Budha Valley N of Yangpachem, about 30°10'38 N 90°30' 18E, 20.VI.2007, 4750 m” (12 males, 3 females, NMB, NMW, CLH).

Remarks. Just a year after the description of this remarkable species, based on two specimens collected by the Russian entomologist Gorbatchev at Zhangmu, southern Tibet near the Nepalese border, a good series has been found in Tibet near Lhasa. This new record also shows that this species is more widespread in Tibet, and the longer series collected by another non-waterbeetle-specialist suggests that it is also not very rare, at least locally.

Female. Similar to male. Anal sternite microreticulate, distinctly wrinkled longitudinally on posterior half and broadly rounded. In the male, the latter is somewhat flattened on the middle.

Distribution. Tibet between 4000 m and 4750 m.

Habitat. All the specimens were collected among gravel on the banks of a small brook of melting and source water at 4750 m ( Figs 6 & 7 ). Fifteen specimens were taken, 12 males and 3 females, bringing the sex ratio for this collection to 4:1. The unusual sex ratio is confirmed by the fact that the two specimens of the type-series were also males.

Figures

FIGURES 6 – 7. Habitat of Ilybiosoma yeti, small brook of melting and source water in Buddha Valley (Tibet South Central) at 4750 m.