Synarmostes niger Paulian, 1979

Ballerio, Alberto, 2021, The Ceratocanthinae of Madagascar and Comoro Islands: a revision of the genera Synarmostes and Goudotostes, and of the flightless Philharmostes, with description of 64 new species (Coleoptera: Scarabaeoidea, Hybosoridae), Fragmenta entomologica 53 (2), pp. 105-282 : 161-162

Synarmostes niger Paulian, 1979

( Figs 25 a-e; 26 e-h; 32 n-p; 35)

Synarmostes niger : Paulian 1979: 62 (key, description, distribution); Ocampo & Ballerio 2006: 190 (listing).

Type locality: “Suberbieville” (now Maevatanana).

Material examined. Holotype, ♂ ( MNHN): / Madag.r Suberb.lle H. Perrier / Muséum Paris 1906 Coll. Léon Fairmaire / Synarmostes tibialis [unreadable] / Synarmostes niger n. sp. R. Paulian det. / Holotype /. 2 paratypes [1 ♂ dissected]: same collecting data as holotype ( MNHN); 1 paratype ♂ [dissected] ( MNHN): / Madagascar Ouest S-P. Antsalova Antsingy, Rés. nat. 9 A. Peyrieras, I-1975 /. Oth- er material examined (not belonging to the type series): 1

♀ ( CASC): / Madagascar: Province de Mahajanga Réserve d’Ankoririka 10.6 km 13° NE de Tsaramandroso 210 m 9-14 Apr. 2001 / 16° 16’ 02” S 046° 02’ 55” E coll: Fisher , Griswold et al. California Acad. of Sciences sifted litter in tropical dry forest collection code: BLF3664 /.

Diagnosis. Synarmostes niger can be differentiated from all other species of Synarmostes by the following combination of characters: a) medium size, b) ventral ocular area large-sized, c) dorsal ocular area present, d) dorsal setation absent (20×), e) wings fully developed, f) pronotum without callosities on disc, g) pronotal punctation on disc made of large transverse comma-shaped punctures, h) elytra with a series of narrow striae formed by two or three rows of very small comma-shaped punctures interspaced by very irregular and very narrow smooth interstriae, i) carinae of elytral apical third irregular (with some weak tubercles or other irregularities). Synarmostes niger belongs to the tibialis group of species. It can be easily distinguished from the other species of the group thanks to the combination of pronotal punctation and elytral sculpturing as indicated under characters g) and h) above.

Description. Size: HL = 1.4 mm; HW = 1.8 mm; PL = 1.6 mm; PW = 2.9 mm; EL = 3.0 mm; EW = 2.8 mm. Overall morphology as in generic diagnosis. Medium-sized volant Synarmostes . Body moderately convex. Black with weak blue metallic sheen, shiny, dorsum glabrous (20×), underside, tarsi and antennae reddish-brown, setation yellowish. Head: W/L ratio = 1.38; clypeal apex obtuse, apical projection protruding and sharp; dorsal ocular area small, interocular distance about 15 times the maximum width of dorsal ocular area, ventral ocular area large; head dorsal surface covered by dense strongly impressed large simple punctation, less dense on disc. Fore margin with some irregular transverse lines. Interpunctural distance of simple impressed punctures once or twice larger than the punctural diameter. Vertex smooth with one continuous transverse impressed line. Pronotum: subrectangular (W/L ratio = 2.10), regularly convex, disc covered by dense short transverse impressed comma-shaped punctures, sides covered by dense shorter and more impressed irregularly comma-shaped punctures. Interpunctural distance shorter than punctural diameter. Scutellum : with small transverse comma-shaped punctures. Elytra: longer than wide (W/L ratio = 0.90); subrectangular (dorsal view); inferior sutural stria reaching humeral area; humeral callus very weak; elytral surface regularly convex, covered by some irregular longitudinal rows of two small impressed horseshoe-shaped punctures with opening directed backward becoming larger and sometimes comma-shaped on distal third. Between each row there is a narrow irregular longitudinal smooth area. Elytral distal third with at least eight raised longitudinal irregular carinae. Wings: fully developed. Male genitalia: aedeagus (L = 1.1 mm) with parameres as in Figs 32 n-o, spiculum gastrale (L = 0.9 mm) as in Fig. 32 p .

Etymology. Latin adjective in the nominative singular, meaning “black”. Paulian did not provide the etymology of the name, which obviously referred to the colour of the beetle.

Distribution and habitat. Known from three localities in western Madagascar: the type locality, i.e., Suberbieville (now Maevatanana, see Viette 1991), Antsalova, and Ankoririka, on the sandstone plateau of Ankarafantsika, where the only specimen collected was found by sifting litter in tropical dry forest. The vegetation cover of the area is classified as “Dry deciduous forest” ( Goodman et al. 2018), also known as “Western dry forest” ( Moat & Smith 2007). The Réserve d’Ankoririka, although not mentioned in Goodman et al. (2018) currently falls within the protect- ed area “Parc National d’Ankarafantsika”.

Figures

Fig. 25 – Synarmostes niger, a, holotype in dorsal view (photo by MNHN); b, holotype in lateral view (photo by MNHN); c, labels of holotype (photo by MNHN); d, paratype in dorsal view (photo by MNHN); e, paratype from Antsalova in dorsal view.

Fig. 32 – Aedeagi and spicula gastrales, a–c, Synarmostes annamariae sp. nov., paratype; d–e, Synarmostes eugenii sp. nov., holotype; f–h, Synarmostes parrilloi sp. nov., holotype; i–j, Synarmostes occidentalis sp. nov., holotype; k–m, Synarmostes zahamenae sp. nov., holotype; n–p, Synarmostes niger, paratype.