Tritonus riana, Short, Andrew Edward Z., 2008

Short, Andrew Edward Z., 2008, Revision of the Afrotropical genus Tritonus Mulsant (Coleoptera: Hydrophilidae), Zootaxa 1855, pp. 41-55 : 53

Tritonus riana sp.n.

( Fig. 15 )

Type Material. Holotype (male): “ MADAGASCAR, 19.xi.2007 / Taolagnaro env., Pic Louis mt./ 25 0’33.09”S 46 58’4.91”E/ hygropetric rock, D. Travnicek lgt.” ( MSEM). Paratypes (6): Same data as holotype (5, MSEM, KSEM); MADAGASCAR: 21 km NE of Esira, Col de Marotaolana, 1100–1200 m, 1– 2.ii.2004, P. Bulirsch (1, NMPC).

Diagnosis. Very similar to T. crenulatus ; see description below for comparison.

Description. Total length 6.7–7.1 mm. This species is very similar to T. crenulatus , with the following differences: smaller size, the median carina of the mesoventrite is more markedly elevated anteriorly, and the crenulations on the anterior margins of ventrites 2 and 3 are present but much less coarse (e.g. intermediate between Figs. 11 and 12 ). Aedeagus as in Fig. 15 .

Etymology. This species is named for the Malagasy word for “cascade” or “waterfall”; it is to be treated as noun in apposition.

Distribution. Madagascar.

Remarks. I had initially considered the single specimen from “ 21 km NE of Esira” to be a possible variant of T. crenulatus , but examination of the additional series provided by D. Travníèek (MSEM) revealed the consistent morphological and size differences provided in the description; consequently, I here consider them as distinct species.

Figures

FIGURES 15 – 21. Aedeagus of Tritonus spp., dorsal view; 15) T. riana; 16) T. steineri; 17) T. riambavy; 18) T. cribratus; 19) T. madagascarensis; 20) T. crenulatus; 21) T. complanatus. Scale bar = 0.45 mm.

FIGURES 11 – 12. Abdomen of Tritonus spp.; 11) T. riambavy; 12) T. crenulatus. Scale bars = 1 mm.