Colotrema socotrana, Plonski, 2017

Plonski, Isidor S., 2017, Colotrema socotrana sp. nov. from Socotra Island, with new records of the genus from Yemen (Coleoptera: Malachiidae), Acta Entomologica Musei Nationalis Pragae (Acta. Ent. Mus. Natl. Pragae) 57, pp. 125-131 : 126-129

Colotrema socotrana sp. nov.

( Figs 1–2 , 5–8 )

Type locality. Environment (georeferenced on the locality label cited below) of Aloove village (12°31′10′′N 54°07′24′′E; see BEZDĚK et al. 2012: 34), Socotra Island, Yemen .

Type material. HOLOTYPE: J ( NMPC), labelled: ‘ YEMEN, SOCOTRA ISLAND / Aloove area, ALOOVE vill. env. / Jatropha unicostata shrubland; / with Boswellia elongata trees / 19.-20.vi.2012 / 12°31.2’N, 54°07.4’E, 221m // SOCOTRA expedition 2012 / J. Bezděk, J. Hájek, V. Hula, / P. Kment, I. Malenovský, / J. Niedobová & L. Purchart leg.’. ALLOTYPE: ♀ ( NMPC), same data as holotype. PARATYPES: 1 J 2 ♀♀ (1 J ( PT #1) and 1 ♀ ( PT #2) in NMPC; 1 ♀ ( PT #3) in IPVA): ‘ YEMEN, SOCOTRA ISLAND / Noged plain, ABATARO / border of sand dunes and / shrubland 12.-13.vi.2012 / 12°22.1’N, 54°03.04’E, 20m // SOCOTRA expedition 2012 / J. Bezděk, J. Hájek, V. Hula, / P. Kment, I. Malenovský, / J. Niedobová & L. Purchart leg.’.

Description of male holotype. Colouration: Head capsule, mouthparts, antennae, pro- and mesothorax, legs, sides and apices of elytra, sternum VIII and pygidium yellow to orange; eyes, metathorax, scutellum and elytra (except sides, apices and suture) black; elytral suture and remaining abdomen lightened to brownish.

Head capsule broader than long, with coriaceous microsculpture and fine whitish setae diverging towards compound eyes. Apical maxillary palpomere polygonal in outline ( Fig. 5 ). Scapus elongate, clavate, as long as pedicel and antennomere I together; adjoining antennomeres longer than broad.

Pronotum transverse, broadest next to apex; apex and base weakly arcuate, sides more strongly arcuate, apical corners rounded, basal corners strongly rounded; side margins distinct; disc moderately convex with coriaceous microsculpture and punctures, whose distance to each other equals 2–3 times their diameter; pubescence similar to that of head capsule. Elytra oblong-ovate; microsculpture, punctures and pubescence similar to those on pronotum; anteapically with circular impression. Front legs with tetramerous tarsi.

Pygidium ( Fig. 6 ) with long basal struts, medially less sclerotized region, and bisinuate apex. Sternite VIII ( Fig. 7 ) with species-specific apex. Median lobe ( Fig. 8 ) subparallel at base and in middle, then conically widened, with 3–4 big endophallic sclerites in middle portion, and big bilateral ankylotic setae at apex.

Variability. The specimens of the type series vary considerably in elytral colouration from almost black elytra with only sides and apices near suture yellow ( Fig. 1 ) to elytra extensively yellow with black colour restricted to longitudinal club-shaped macula on the disc extending from humeral bulges to the apical third of elytra ( Fig. 2 )

Sexual dimorphism. Males with longer antennae, modified apical maxillary palpomere, anteapical circular elytral impression and tetramerous fore tarsi. Females with shorter antennae, broad and apically truncated apical maxillary palpomere, pentamerous foretarsi, and without elytral impressions.

Measurements.AL = 0.72–1.06 (holotype 0.91 mm); HW = 0.54–0.65 (holotype 0.59 mm); IOW = 0.39–0.50 (holotype 0.39 mm); PW = 0.65–0.76 (holotype 0.65 mm); PL = 0.37–0.46 (holotype 0.39 mm); EW = 0.91–1.09 (holotype 0.96 mm); EL = 1.17–1.37 (holotype 1.17 mm). Differential diagnosis. Chromatically, C. socotrana sp. nov. belongs to a group, whose members possess a completely orange pronotum and predominantly black elytra with yellow sides, apices and suture (the latter to varying extents). The most similar species is C. barbertonica Wittmer, 1991 from South Africa, which also possesses a completely orange coloured head capsule, but differs in having bicolorous extremities (cf. WITTMER 1991: 240). In addition, C. socotrana sp. nov. is well characterized by the form of the male maxillary palpi (cf. WITTMER 1991: Figs 49–50 for C. barbertonica ) and the last abdominal segments. Furthermore, C. socotrana sp. nov. can be distinguished from the species occurring in the Arabian Peninsula by the characters given in the key below.

Etymology. The species epithet is a Latin adjective derived from the place of origin and means ‘Socotran’.

Distribution. Endemic to Socotra Island, Yemen.

Figures

Figs 1–4. Habitus of Colotrema. 1–2 Colotrema socotrana sp. nov.: 1 – female allotype; 2 – male paratype #1; 3 – C. assirensis Wittmer, 1979; 4 – C. testacea wajjensis Wittmer, 1980. Not in scale.

Figs 5–8. Details of holotype of Colotrema socotrana sp. nov.5 – left maxillary palpus, ventral; 6 – pygidium, ventral view; 7 – sternite VIII, dorsal view; 8 – median lobe, lateral view. Scale bar = 0.2 mm.