Synarmostes occidentalis, Ballerio, 2021

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 : 162

Synarmostes occidentalis sp. nov.

( Figs 10 b , 26 a-d, 32 i-j, 35) http://zoobank.org/ urn:lsid:zoobank.org:act:9B0A385C-B0FB-4476-9AE9-D7032297CB2B

Type series. Holotype, ♂, deposited in the collection of the California Academy of Sciences, San Francisco, CA, USA, labelled as follows: / CASTYPE 20258 / CASENT 5504528 / Madagascar: Mahajanga Prov. Forêt de Tsimembo 11.0 km 346° NNW Soatana elev. 50 m 21-25 Nov. 2001 18° 59’ 43” S 044° 26’ 37” E / coll. Fisher, Griswold et al. California Acad. of Sciences sifted litter (leaf mold, rotten wood) in tropical dry forest coll. code: BLF4508/ Synarmostes occidentalis n. sp. det. A. Ballerio 2020 Holotypus ♂ / [distended, glued on card, dissected, male genitalia glued on a separate card, same pin]. Paratypes: 1 ♀ ( CASC), same collecting data as holotype .

Diagnosis. Synarmostes occidentalis 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 small transverse sparse comma-shaped punctures, h) elytra with a series of narrow striae formed by two or three rows of comma-shaped punctures interspaced by wider interstriae almost smooth but with some sparse fine simple punctures, i) carinae of elytral apical third irregular (with some weak tubercles or other irregularities). Synarmostes occidentalis 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 (in particular because of the interstriae with sparse simple punctation) as indicated under characters g) and h) above.

Description. Size: HL = 0.7 mm; HW = 1.2 mm; PL = 1.1 mm; PW = 2.1 mm; EL = 2.2 mm; EW = 2.1 mm. Overall morphology as in generic diagnosis. Medium-sized volant Synarmostes . Body moderately convex. Black, shiny, dorsum glabrous (20×), underside, tarsi and antennae reddish-brown, setation yellowish. Head: W/L ratio = 1.38; clypeal apex obtuse, apical projection small, protruding and sharp, sides almost rectilinear; genae distinctly produced outwards, acute; genal canthus complete, fused with the occipital portion of head; dorsal ocular area small, interocular distance about 15 times the maximum width of dorsal ocular area, ventral ocular area large-sized, head dorsal surface covered by dense impressed small simple punctation, disc smooth. Fore margin with some irregular transverse lines. Interpunctural distance of simple impressed punctures once or twice larger than the punctural diameter. Vertex with a transverse impressed line interrupted in the middle. Pronotum: subrectangular (W/L ratio = 1.85), regularly convex, base and sides smooth, disc covered by short transverse impressed comma-shaped punctures, becoming longitudinally orient- ed towards sides. Interpunctural distance about as long as punctural diameter. Scutellum : with small transverse comma-shaped punctures. Elytra: longer than wide (W/L ratio = 0.80); subrectangular (dorsal view); inferior sutural stria reaching humeral area although under the form of a shallow fine line; humeral callus very weak; elytral surface regularly convex, covered by some irregular longitudinal rows of two or three small impressed horseshoe-shaped punctures with opening directed backward becoming larger and shallower on distal third mixed to very fine simple punctures. Between each row there is a wide longitudinal smooth area with few sparse simple very fine shallow punctures. Elytral distal third with at least seven raised longitudinal irregular carinae. Wings: fully developed ( Fig. 10 b ). Male genitalia: aedeagus (L = 1.0 mm) with parameres as in Figs 32 i-j.

Etymology. Latin adjective in the nominative singular meaning “western”, since this species occurs in the western province of the island.

Distribution and habitat. Known only from the type locality in western Madagascar. The type series was collected by sifting litter (leaf mold, rotten wood) 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 area falls within the protected area “Paysage harmonieux protegé du complexe Tsimembo Manambolomaty”.

Figures

Fig. 10 – Wings. a, Synarmostes tibialis; b, Synarmostes occidentalis sp. nov.; c, Synarmostes sp. C; d, Philharmostes metallicus sp. nov.; e, Synarmostes makirovanae sp. nov.; f, Goudotostes laevis sp. nov..

Fig. 26 – Synarmostes occidentalis sp. nov., a, dorsal view of distended holotype; b, ventral view of rolled up paratype; c, dorsal view of rolled up paratype; d, lateral view of rolled up paratype; Synarmostes niger (Réserve d’Ankoririka), e, dorsal view of distended specimen; f, ventral view of rolled up specimen; g, dorsal view of rolled up specimen; h, lateral view of rolled up specimen.

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.