Triodontus hanskii Frolov, 2010

Frolov, Andrey V., Montreuil, Olivier & Akhmetova, Lilia A., 2016, Review of the Madagascan Orphninae (Coleoptera: Scarabaeidae) with a revision of the genus Triodontus Westwood, Zootaxa 4207 (1), pp. 1-93 : 88

Triodontus hanskii Frolov, 2010

( Figs. 45 A–G)

Triodontus hanskii Frolov, 2010b: 1031 .

Type material examined. Holotype, male, “ MADAGASCAR Ambatotsirongorongo Feb 2005 fish baited trap Ilkka Hanski leg. / Triodontus hanskii Frolov 2010 HOLOTYPUS ” ( ZIN) .

Diagnosis. From other species with 2 medial tubercles on the pronotum and simple shape of the 6th abdominal sternite in males ( T. owas Westwood , T. itremoi Paulian , T. copridoides Paulian ), T. hanskii can be separated by having the parameres without teeth and notches laterally ( Fig. 45 E).

Description. Male. Body length 10.1 mm. Body strongly shiny, uniformly colored ( Figs. 45 A–B). Color of head, pronotum, and elytra dark brown; legs, antennae, and underside of the body brown.

Frontoclypeus convex anteriorly, rounded laterally, anterior margin crenulate and setose in dorsal view. Eyes relatively small (diameter slightly smaller than the distance between eye and gula in ventral view), incompletely divided by canthus into small, dorsal and large, ventral parts. Frontoclypeus with small but distinct tubercles mediad of each eye and with short horn in center of frontoclypeus.

Pronotum with 2 obtuse tubercles in the middle and with excavations aside the tubercles. Lateral margins with wide border appearing somewhat crenulate in dorsal view. Anterior margin with wide, smooth border. Posterior margin with fine border; not crenulate; punctate with small, narrow, longitudinal punctures laterally. Surface of most pronotum smooth, anterior angles with a few coarse punctures.

Scutellum rounded apically, visible part is about 1/15 length of elytra.

Elytra convex, with distinct humeral humps. Maximum width approximately at middle. Elytra with 10 feebly visible striae and with oblique line from base of 6th stria to approximately middle of 8th stria. Stria with small, indistinct punctures. Intervals with minute punctures, almost smooth. Base of elytra with an irregular row of coarse punctures each bearing small, yellow seta.

Sternite 8 medially about 3 times as short as other sternites combined, slightly sinuate apically, without tubercles or distinct concavities in the middle ( Fig. 45 F).

Parameres with upper lobes somewhat tapering apically and sinuate on lateral margin basally ( Fig. 45 E). Internal sac of aedeagus with a somewhat pentagonal main sclerite and smaller auxiliary sclerites ( Fig. 45 D).

Female. Unknown.

Distribution and habitat. The species is known from a single specimen collected in Ambatotsirongorongo forest in Tolagnaro region of South Madagascar. This is the southernmost locality of Triodontus species known to date and it is also the southernmost remnant of indigenous rain forest on the island ( Fig. 45 G). The only known specimen of T. hanskii was collected in a pitfall trap baited with fish carrion. Short trap exposure (1 day and night) suggests that the specimen was attracted to carrion rather than captured accidently.

Figures

FIGURE 45. Triodontus hanskii, holotype male. Habitus in dorsal (A) and dorsolateral view (B), labels (C), internal sac of aedeagus (D), aedeagus in lateral view and parameres in dorsal and ventral view (E), abdomen (F), distributional records (G).