Tritonus madagascarensis, Short, Andrew Edward Z., 2008

Short, Andrew Edward Z., 2008, Revision of the Afrotropical genus Tritonus Mulsant (Coleoptera: Hydrophilidae), Zootaxa 1855, pp. 41-55 : 51-53

Tritonus madagascarensis sp.n.

( Fig. 19 )

Type Material. Holotype (male): “ MADAGASCAR (144): Antsiranana/ Andapa: R. Masiaposa (Crossing R.N./ 3b at km 5–6) about & km upstr. Road/ bridge, 700 m, 10.xi.2001 / Gerecke & Goldschmidt” ( NMW). Paratype (1): Same data as holotype (1, KSEM).

Diagnosis. This species is most similar to the Mauritian endemic T. cribratus , from which it can be distinguished by the less pronounced systematic punctures, and lack of distinct microreticulation of the metafemora. Other species of similar size and shape (e.g. T. riambavy , T. steineri ) possess much coarser ground punctation.

Description. Total length 6.4 mm. Color. Dorsum black with a general shagreen. Pronotum with a few dark black patches around margins. Elytra with indistinct green iridescent patches along distal margins. Head.

Ground punctation fine to very fine; irregular in size. Systematic punctures distinct; 3– 4 x as large as largest surrounding ground punctures; on clypeus bearing short decumbent setae; those on frons anterior to each eye relatively long and erect. Antennae with club distinctly shorter in length than segments 2–6 combined. Maxillary palpi short, apical segment ca. 1.5× length of penultimate segment; penultimate segment and segment 2 subequal in length. Mentum with anterior margin slightly convex; anterior third with coarse, transverse microsculpture; posteriorly with a few fine, irregularly scattered punctures. Anterior margin of head moderately wide and broadly rounded. Thorax. Ground punctation on pronotum and elytra very fine; almost appearing absent. Pronotal and elytral systematic punctures large and distinct; bearing short setae. Prosternum slightly tectiform with a sharp, narrow and glabrous median carina. Median carina distinctly elevated and slightly dilated at anterior margin. Mesoventrite elevated medially into a distinct narrow carina; surface of carina narrowly glabrous. Carina slightly depressed, appearing almost concave in lateral view. Metasternum with large elevated glabrous region that is ca. one third as wide as long. Metafemora glabrous and shiny; weakly impressed microsculpture present, but barely detectable on central face of femora. Abdomen. Posteromedial glabrous region of ventrite 1 small, somewhat indistinct, less than one third as wide as region on ventrite 2. Glabrous region of ventrite hemi-ovoid; distinctly less than one third the width of the ventrite. Anterior margins of ventrites 2–4 appearing finely crenulate. Aedeagus as in Fig. 19 .

Etymology. Named for the country of Madagascar.

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.