Triodontus hova ( Fairmaire, 1868 )

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 : 58-61

Triodontus hova ( Fairmaire, 1868)

( Figs. 29 A–H; 30A–C)

Orphnus hova Fairmaire, 1868: 783 ; Fairmaire 1897: 100. Triodontus hova (Fairmaire) : Paulian 1977: 1217.

Orphnus distinctus Fairmaire, 1897: 100 : junior objective synonym. Orphnus nigrita Brancsik, 1893: 224 , new synonym

Triodontus nigritus (Brancsik) : Paulian 1937: 13, 1977: 1217.

Type material examined. Orphnus hova : holotype ( Figs. 29 A, D), male, “MUSEUM PARIS MADAGASCAR Collection Leon Fairmaire 1906 / Orphnus distinctus hova [Fair] Madag. / TYPE” (MNHN).

Orphnus nigrita : syntype ( Fig. 30 B), female, “Fauna Ins. Nossibe / Coll. Dr. Ed. Knirsch. Orphnus nigrita Brancsik Determ. Dr. Knirsch / Co-Typus / CNHM 1955 Karl Brancsik Colln. ex Eduard Knirsch” (FMNH); syntype, female, “Coll. Dr. Ed. Knirsch. Orphnus nigrita Brancsik Determ. Dr. Knirsch / Typus / Typ/ CNHM 1955 Karl Brancsik Colln. ex Eduard Knirsch” (FMNH).

Additional material examined. MADAGASCAR: Antsiranana: one male, “ Sambirano N.O. Madagasc. [ Sambirano , 13°43′00″S, 48°22′00″E]” ( MNHN) ; one female, “Museum Paris Madagascar Nossi-Be H. Pierron 1885 [ Nosy Be Island , 1885, H. Pierron leg.]” ( MNHN) ; six males, six females, “Nossi-Be Madagascar ” ( MNHN) ; one male, “ Madagascar 5415 / Nosy-Be VII 1983 ” ( MNHN) ; Nosy Be Island, two females ( NMPC) ; two females “Nossi-Be 1937 Cie. Sucriere” (IRSNB); four females, “Nossi-Be Hellville Tschitscherine [Nosy Be Island, Hellville , 13°24′00″S, 48°16′00″E, Tschitscherine leg.]” ( MNHN) ; one male, “ Madagascar Sambirano Nosy-Be foret de Lokobe XII-58 Andria Robinson [Nosy Be, Lokobe Forest , 13°22′59″S, 48°19′59″E, XII.1958, A. Robinson leg.]” ( MNHN) ; one female, “ MADAGASCAR: Province d'Antsiranana, Ampasindava, Foret d'Ambilanivy , 3.9 km 181° S Ambaliha [13°47′54″S, 49°09′42″E] elev. 600 m. 4–9 March 2001 ” ( CASC) ; Mahajanga: one male, two females, “ Madagascar Ouest: Antsalova , Antsingy. R.N. 9 I.1975 A. Peyrieras [Antsalova, Antsingy, " Reserve Naturelle 9", 19°06′00″S, 44°52′59″E]” ( MNHN) ; one male, “ Madagascar Siberbielle H.Perrier [Suberbieville = Maevatanana , 16°57′00″S, 46°49′59″E]” ( MNHN) ; one male, “ Madagascar Ile de Beraphia Cote Ouest 1934 [ Beraphia Island , 14°01′59″S, 47°48′00″E, 1934]” ( MNHN) ; one male, “ Ankarafantsika Forest [16°09′00″S, 47°01′59″E] // MADAGASCAR I .1956 C.Koch leg.” (MHNG); Madagascar (no exact locality): one male ( IRSNB) .

Diagnosis. Triodontus hova is similar to T. nitidulus and T. bicavatus in having 3 tubercles on the central pronotal bulge and relatively large outer lobes of parameres but differs from them in the larger overall size of the body, almost flat elytral intervals (as opposed to being somewhat convex in T. nitidulus and T. bicavatus ), and in having the abdominal sternite 8 wider and less sinuate medially.

Description. Male. Color of head, pronotum and elytra dark brown to brown; legs, antennae and underside of the body brown ( Figs. 29 A, C, E).

Frontoclypeus convex anteriorly, rounded laterally, anterior margin crenulate and setose in dorsal view. Eyes relatively small (their 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 tubercles mediad of each eye and in some specimens with a horn in center of frontoclypeus; horn, when the most developed, is about as long as the width of the head, acutely rounded apically, straight to somewhat curved caudally at the apex, slightly rugose on posterior side.

Pronotum with a bulge medially, with excavations aside the bulge, and with 2 ridge-shaped tubercles laterally of each excavation. Central bulge has 3 small but distinct tubercles. Lateral margins with wide border appearing somewhat crenulate in dorsal view, with a row of brown setae. Anterior margin with wide, smooth border. Posterior margin with fine border, not crenulate, punctate with narrow longitudinal punctures. Surface of pronotum smooth.

Scutellum rounded apically, its visible part is about 1/12 length of elytra.

Elytra convex, with distinct humeral humps, their maximum width is approximately at middle. Elytra with 10 fine striae on disc and with oblique line from base of 6th stria to approximately middle of 8th stria. Stria with small punctures. Intervals with minute punctures, almost smooth and flat. Base of elytra with irregular row of coarse punctures.

Sternite 8 relatively wide, feebly sinuate medially (in ventral view), and somewhat excavated ( Fig. 30 A).

Parameres ( Fig. 29 F) with large outer lobes covering inner lobes (in lateral view). Proximal parts of outer lobes with small keel-shaped processes. Internal sac of the aedeagus with 1 strongly sclerotized symmetrical, somewhat pentagonal sclerite, and with 2 similar protuberances of the membrane ( Fig. 29 G).

Female. Females ( Figs. 29 B; 30B) differ from males in having long apical spur on protibiae, absence of head and pronotum armature including tubercles mediad of each eye, densely punctate dorsal side of head, and longer abdominal sternites including 6th sternite, which is evenly rounded apically.

Variation. Pronotal and head armature of males is subject to allometric variability from fully developed (as described above) to almost undeveloped (with the males having small frontoclypeal tubercles in the middle and small fossa on the pronotum anteriorly. Body length of examined specimens varied from 9.5–12.0 mm (males) and from 9.0–14.0 mm (females).

Distribution. Triodontus hova occurs in western and northwestern Madagascar ( Fig. 29 H). Previously it was recorded mostly from Nosy Be Island ( Paulian 1977), but it is also known from Nosy Berafia Island, Sambirano River basin, and from three distant localities in the western Madagascar up to Tsingy de Bemaraha Nature Reserve in the south.

Remarks. Synonymy of the names Orphnus distinctus Fairmaire and O. hova Fairmaire was discussed by Paulian (1977). Brancsik (1893) described Orphnus nigrita based on two females from Nosy Be Island. He noted that they differed from T. hova in larger size (up to 14 mm) and darker, almost black coloration. Although most of T. hova specimens we examined are smaller (up to 12 mm) and more or less brown rather than black, we think that the type specimens of O. nigrita might be aberrant forms of T. hova or lie within the interspecific variability of this species. Other characters, but the size and color, agree well with the females of T. hova as well as the occurrence on Nosy Be. Therefore the new synonymy is here proposed.

Figures

FIGURE 29. Triodontus hova. Habitus in dorsal view (A, C—male [A—holotype], B—female), labels of holotype (D), habitus of male in dorso-lateral view (E), aedeagus in lateral view and parameres in dorsal and ventral view (F), internal sac of aedeagus (G), distributional records (H).

FIGURE 30. Triodontus hova. Abdomen of male (A), syntype of O. nigrita, habitus in dorsal view (B), protibia (C, male left, female right).