Triodontus alticola Paulian, 1977

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 : 80-82

Triodontus alticola Paulian, 1977

( Figs. 41 A–H)

Triodontus alticola Paulian, 1977: 1215 .

Triodontus maroantsetrae Paulian, 1977: 1219 , new synonym

Type material examined. Triodontus alticola . Holotype ( Figs. 41 C, D), male, “ Madagascar Ambohitsitondrona [Toamasina Province] XI-1949 Michel / Triodontus alticola n. sp. R. Paulian det. / TYPE ” ( MNHN).

Paratypes: two females with the same locality and date label ( MNHN) ; two males and two females with the same locality label but the date “ XII-52 ” ( MNHN) ; one male, “ Madagascar Sambava [Antsiranana Province] XI [...] Vadon !” ( MNHN) ; one male, “ Madagascar Ambodivoangy [Toamasina Province] I.1950 Vadon !” ( MNHN) .

Triodontus maroantsetrae . Holotype, male, “ Madagascar Ron Maroantsetra XII.35 Vadon Antakotako / MUSEUM PARIS 1938 J. Vadon et E. Lebis / TYPE / Triodontus maroantsetrae n. sp. R. Paulian det.” ( MNHN) .

Additional material examined. MADAGASCAR: Toamasina: two males, “ Madagascar Ambohitsitondrona II-1948 Michel [15°34′59″S, 50°01′00″E]” ( MNHN) ; one male, “ Madagascar Ambodivoangy [15°17′49″S, 49°36′47″E] I.1946 Vadon!” ( MNHN) ; one male, same label but XII.1947 (MNHN); one female, “ Madagascar Antakotako [15°19′00″S, 49°48′00″E] II.1946 Vadon!” ( MNHN) ; one male, “ Madagascar Est distr. Mananara - N. Antanambe Vadon et Peyrieras [ Mananara District , Antanambe, 16°25′59″S, 49°51′00″E]” ( MNHN) ; four males, one female, “ Madagascar Ambohitsitondrona I-1946 Vadon! [15°34′59″S, 50°01′00″E]” ( MNHN) ; one male, “ Madagascar Ambohitsitondrona 25-I-1948 Michel [15°34′59″S, 50°01′00″E, 25.I.1948]” ( MNHN) ; one male, one female, “ Madagascar Ambohitsitondrona X-1947 Vadon! [15°34′59″S, 50°01′00″E]” ( MNHN) .

Diagnosis. Triodontus alticola can be separated from other species of the genus by the characteristic shape of the parameres having the outer lobes long, curved downward and inward; with more-or-less separated, strongly sclerotized lateral parts and membranous, overlapping medial parts; and without lateral notches.

Description. Male. Color of head, pronotum, and elytra dark brown, legs, antennae, and underside of the body slightly paler ( Figs. 41 A, C).

Frontoclypeus slightly convex anteriorly, obtusely rounded laterally, anterior margin 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 tubercles mediad of each eye and with a horn in center. The horn is longer than width of the head, acutely rounded apically, somewhat curved caudally, with slightly flattened anterior side and slightly rugose posterior side.

Pronotum with a bulge medially in center, with excavations each side of bulge, and with 2 ridge-shaped tubercles laterally of each excavation. The median bulge with 2 distinct tubercles and somewhat excavated between the tubercles. Lateral margins with wide border bearing a row of brown setae. Anterior margin with wide, smooth border, almost not sinuate medially. Posterior margin with fine border, not crenulate, punctate with a few narrow, longitudinal punctures. Surface of most pronotum punctate with minute, feebly visible puctures.

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 striae; stria 1 (sutural) distinct, other feebly marked with small punctures. Intervals with minute punctures, almost smooth. Base of elytra with an irregular row of coarse punctures.

Abdominal sternite 8 medially deeply sinuate, without tubercles or concavities in middle ( Fig. 41 G).

Parameres ( Fig. 41 E) with outer lobes long, curved downward and inward; with more-or-less separated, strongly sclerotized lateral parts and membranous, overlapping medial parts; and without lateral notches. Internal sac of aedeagus with a hoof-shaped sclerite ( Fig. 41 F).

Female. Females ( Fig. 41 B) differ from males in having a protibial apical spur; absence of head and pronotum armature including tubercles mediad of each eye; and longer abdominal sternites including 6th sternite, which is evenly rounded apically.

Variation. The pronotal and head armature of males is less developed in some specimens. Body length of examined specimens varied from 8.8–12.0 mm (males) and from 9.0–11.0 mm (females).

Distribution. This species is known from a few localities in the northeastern part of the island, mostly north of Antongil Bay ( Fig. 41 H).

Remarks. Triodontus maroantsetrae was described from one male specimen from Antakotako. Comparison of this specimen with the type series of T. alticola has shown that they have similar shape of the parameres. The only difference is the feebly developed frontoclypeal horn and almost absent ridges and tubercles on the pronotum in the holotype of T. maroantsetrae . We believe all these specimens fall within the limits of allometric variability of one species, therefore the new synonymy is here proposed.

Figures

FIGURE 41. Triodontus alticola, holotype male (C, D, E, F), male (A), female (B). Habitus in dorsal view (A, B, C), aedeagus in lateral view and parameres in dorsal and ventral view (E), labels of holotype (D), internal sac of aedeagus (F), abdomen (G), distributional records (H).