Synarmostes grinteri, 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 : 156-157

Synarmostes grinteri sp. nov.

( Figs 20 a-d, 29 q-s, 35) http://zoobank.org/ urn:lsid:zoobank.org:act:30FEB9D8-C18D-49B2-A6F2-AAF16ECF4FBC

Type series. Holotype, ♂, deposited in the collection of the California Academy of Sciences, San Francisco, CA, USA, labelled as follows: / CASTYPE 20253 / Comoros: Mohéli, Ouallah elev. 500 m 12°18’13”S 043°40’06”E 18- 19 January 2009 Calif. Acad. of Sciences coll. B. L. Fisher et al. sifted litter rainforest collection code: BLF 20682/ Synarmostes grinteri n. sp. det. A. Ballerio 2020 Holotypus ♂ / [distended, glued on card, dissected, male genitalia glued in DMHF resin on a separate card, same pin]. Paratypes [10 ♂♂ dissected]: 204 specimens (160 in CASC and 44 in ABCB), same collecting data as holotype. 14 specimens (12 in CASC and 2 in ABCB): / Comoros: Mohéli, Ouallah elev. 750 m 12°17’46”S 043°40’34”E 19 – 20 January 2009 Calif. Acad. of Sciences coll. B. L. Fisher et al. montane rainforest collection code: BLF 20738 /.

Diagnosis. Synarmostes grinteri sp. nov. can be differentiated from all other species of Synarmostes by the following combination of characters: a) small size, b) ventral ocular area small-sized, c) dorsal ocular area present, d) dorsal setation present (20×), e) flightlessness, f) carinae of elytral apical third regular (without tubercles or other irregularities), g) scutellum smooth, without punctation, h) pronotum with an anteromedian area smooth, i) elytral horseshoe-shaped punctation sparse and small, j) parameres distinctly falcate in lateral view (more falcate than in S. karthalaensis sp. nov.), k) elytral inferior sutural stria ending before humeral area. Synarmostes grinteri sp. nov. belongs to the humilis group of species and can be distinguished from the other species of the group only with the examination of the aedeagus, which has the distinctive shape indicated under letter j) above.

Description. Size: HL = 0.7 mm; HW = 1.0 mm; PL = 0.9 mm; PW = 1.6 mm; EL = 1.7 mm; EW = 1.5 mm. Overall morphology as in generic diagnosis. Small-sized flightless Synarmostes . Body strongly convex. Dark-brown with bronze sheen, shiny, dorsum with setigerous punctures bearing a medium-sized fine seta (20×), underside, tarsi and antennae reddish-brown, setation yellowish-brown. Head: W/L ratio = 1.52, clypeal apex obtuse, apical projection distinctly protruding and sharp; dorsal ocular area small, interocular distance about 23 times the maximum width of dorsal ocular area, ventral ocular area small; head dorsal surface with disc almost smooth with only a few simple shallow punctures, sides of disc covered by sparse medium-sized comma-shaped punctation mixed to some horseshoe-shaped punctures with opening direct- ed inwards. Fore margin with one or two transverse large comma-shaped punctures. Interpunctural distance of punctures irregular: half their width or once or twice larger than their width. Vertex smooth with a transverse impressed line shortly interrupted in the middle. Pronotum: subrectangular (W/L ratio = 1.64), regularly convex, pronotal surface with disc almost smooth, with only some sparse shallow simple punctures, sides covered by medium-sized sparse shallow transverse comma-shaped punctures, each one having a simple setigerous puncture inside. Interpunctural distance shorter than punctural width. Scutellum : almost completely smooth. Elytra: longer than wide (W/L ratio = 0.86); subrectangular (dorsal view); inferior sutural stria ending before humeral area; humeral callus indistinct; elytral surface regularly convex, uniformly covered by sparse shallow punctation. Interpunctiural distance once to thrice the maximum width of punctures. Punctures transverse comma-shaped near base and sides of elytra, becoming horseshoe-shaped punctures with opening directed backwards on medial third, each one having a simple setigerous puncture inside. Elytral distal third with four raised longitudinal carinae (excluding elytral suture) sometimes with a longitudinal impressed irregular line between them. Wings: flightless (apterous). Male genitalia: aedeagus (L = 1.0 mm) with parameres as in Figs 29 q-r, spiculum gastrale (L = 0.8 mm) as in Fig. 29 s .

Etymology. Noun in the genitive case. Named after Christopher Grinter, collection manager at CAS.

Distribution and habitat. Known only from the type locality. The type series was collected by sifting leaf litter in rainforest.

Figures

Fig. 20 – Synarmostes grinteri sp. nov., a, dorsal view of distended paratype; b, ventral view of rolled up paratype; c, dorsal view of rolled up paratype; d, lateral view of rolled up paratype; Synarmostes karthalaensis sp. nov., e, dorsal view of distended paratype; f, ventral view of rolled up paratype; g, dorsal view of rolled up paratype; h, lateral view of rolled up paratype.

Fig. 29 – Aedeagi and spicula gastrales, a, Synarmostes humilis, holotype. b–d, Synarmostes humilis (Mont Combani); e–g, Synarmostes benaraensis sp. nov., paratype; h–j, Synarmostes chonguimontis sp. nov., paratype; k–m, Synarmostes dapaniensis sp. nov., paratype; n–p, Synarmostes karthalaenisis sp. nov., paratype; q–s, Synarmostes grinteri sp. nov., paratype.