Genus Triodontus (Scarabaeidae, Orphninae)

Orphninae, Triodontus itremoi

Genus Triodontus Westwood, 1846


Type species: Orphnus nitidulus Guérin-Méneville, 1844, by monotypy.


Body small to mid-sized (length 6.5 mm to 17 mm), brown to almost black. Mandibles subsymmetrical. Clypeus with rounded anterior margin, with tubercle or horn in males; females have clypeus without tubercles. Pronotum of larger males of most species with a bulge medially, large excavations aside the bulge, and with two ridge-shaped tubercles laterally of each excavation. Females with convex pronotum without excavations or tubercles. Propleurae smoothly convex, without carinae separating anterolateral areas from basal area. Scutellum rounded apically, about 1/15 length of elytra. Elytra convex, smooth except for base, with marked striae in some species, with feebly marked humeral umbones. Wings fully developed. Metepisternon triangular, tapering caudally, with slightly widened anterodorsal angle slightly overlapping epypleuron. Anterior tibiae of typical scarabaeoids shape, with 3 relatively large outer teeth. Phallobase strongly sclerotized dorsally and with a thin membrane ventrally. Parameres relatively short, complex, consisting of medial and lateral parts, without setae. Internal sac of aedeagus with one characteristic symmetrical sclerite (or group of fused sclerites).

Species composition. 14 species are known.

Distribution. Endemic to Madagascar. Species are distributed throughout the island but mostly in the eastern and north-eastern part. The majority of the localities agree well with current distribution of remnants of indigenous forests.


Benderitter, E. (1914) Description d'un Orphnidius nouveau de Madagascar. Bulletin de la Société entomologique de France, 291.

Brancsik, K. (1893) Beiträge zur Kenntniss Nossibés und dessen Fauna nach Sendungen und Mittheilungen des Herrn P. Frey. Jahresheft des Naturwissenschaftlichen Vereines des Trencsiner Comitates, 202--258.

Fairmaire, L. (1868) Notes sur les Coléoptères receuillis par Charles Coquerel a Madagascar et sur les cotes d'Afrique. Annales de la Societe entomologique de France, 4, 753-820.

Fairmaire, L. (1905) Materiaux pour la faune coleopterique de la region Malgache (19e note). Annales de la Société Entomologique de Belgique, 49, 114-138.

Frolov, A. V. (2010) A new species of the genus Triodontus (Coleoptera, Scarabaeidae, Orphninae) from Southern Madagascar. Entomological Review, 90, 1031-1034.

Guérin-Méneville, F. E. (1844) Iconographie du Règne Animal de G.Cuvier. Part 7. Insectes: Paris: Ballière.

Paulian, R. (1977) Les Orphnidae de Madagascar. Bulletin du Muséum National d'histoire naturelle, Paris. Ser. 3., 411, 1199-1223.

Westwood, J. O. (1845) On the lamellicorn beetles which possess exserted mandibles and labrum, and 10-jointed antennae. Transactions of the Entomological Society of London, 4, 155-180.

Westwood, J. O. (1852) On the Lamellicorn beetles which possess exserted mandibles and labrum, and 10-jointed antennae. Being a supplement to a memoir published in the fourth volume of the Transactions of the Entomological Society. Transactions of the Entomological Society of London, 59-74.