Tritonus steineri, Short, Andrew Edward Z., 2008

Short, Andrew Edward Z., 2008, Revision of the Afrotropical genus Tritonus Mulsant (Coleoptera: Hydrophilidae), Zootaxa 1855, pp. 41-55 : 54-55

Tritonus steineri sp.n.

( Fig. 16 )

Type Material. Holotype (male): “ MADAGASCAR: Prov./ Fianarantsoa, 32 km / S. Ambositra, 1400 m / 25 March 1990 ”, “In seepage over/ exposed granite/ cliff face”, “W. E. Steiner,/ C. Kremen,/ V. Razafimahatratra/ collectors” ( NMNH).

Diagnosis. This species is most similar to T. riambavy , which it can be distinguished by the less anteriorly elevated carina of the mesoventrite. The generally coarse ground punctation, which obscures the comparatively small systematic punctures, also serves to distinguish this species from the remaining members of the genus.

Description. Total length 6.4 mm. Color. Dorsum black with a general shagreen. Pronotum with dark black patches around margins. Elytra with bright iridescent blue-green spots an distal halves. Head. Ground punctation irregular in size, composed of fine, barely detectable points to larger punctures nearly as large as systematic punctures. Systematic punctures barely larger than the largest surrounding ground punctures; on clypeus bearing short decumbent setae; those on frons anterior to each eye relatively long and erect. Antennae with club subequal in length to segments 2–6. Maxillary palpi short, apical segment 1.5× length of penultimate segment; penultimate segment and segment 2 subequal in length. Mentum with anterior margin convex; anteriorly with coarse, transverse and microsculpture; posteriorly with a few irregularly scattered punctures. Anterior margin of head broadly and evenly rounded. Thorax. Ground punctation on pronotum and elytra of dense and course; composed of mixed, irregular sizes that are slightly larger than those of the head. Pronotal systematic punctures slightly but distinctly larger than largest surrounding ground punctation and bearing short setae. Elytral systematic punctures bearing short setae and similar in size to largest surrounding ground punctures. Prosternum strongly bulged centrally, but without sharp median carina; with a small, blunt anteromedial tooth. Mesoventrite with broad, slightly elevated region centrally but without a distinct carina; anterior third of raised area forming a low, narrow pubescent ridge; anterior margin of raised area with a small, glabrous tubercle that is not elevated higher than the level of the surrounding raised area. Metasternum with very large elevated pentagonal glabrous region, almost twice as wide as long. Metafemora glabrous and shiny; weakly impressed microsculpture present but restricted to extreme anterior and distal margins. Abdomen. Posteromedial glabrous region of ventrite 1 distinct, ca. 0.75 as wide as region on ventrite 2. Glabrous region of ventrite 2 broad, nearly trapezoidal in shape; one 0.33 the width of the ventrite. Anterior margins of ventrites 1–3 not crenulate, but with a loosely wrinkled appearance. Aedeagus as in Fig. 16 .

Etymology. Named in honor of Warren E. Steiner, Jr., collector of this new species and a person who has helped the author during numerous visits to the US National Museum.

Distribution. Madagascar. Known only from the type locality.

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.