Neobarombiella socotrana, Bolz & Wagner, 2014

Bolz, Helmut & Wagner, Thomas, 2014, A new AfrotropicalNeobarombiella species from Socotra Island (Coleoptera: Chrysomelidae: Galerucinae), Acta Entomologica Musei Nationalis Pragae 54, pp. 277-281 : 278-280

Neobarombiella socotrana sp. nov.

( Figs 1–5 )

Type locality. Yemen, Socotra Island, Dixam plateau, Tudhen, 12°33.7′N, 53°59.9′E.

Type material examined. HOLOTYPE: J, ‘ YEMEN, SOCOTRA ISLAND, Dixam plateau, TUDHEN, shrubland with Commiphora planifrons , 18.+ 22.vi.2012, 12°32.7′N, 53°59.9′E, 1135m’ / ‘ SOCOTRA expedition 2012, J. Bezděk, J. Hájek, V. Hula, P. Kment, I. Malenovský, J. Niedobová & L. Purchart leg.’ / ‘ HOLOTYPE, Neobarombiella socotrana, Bolz & Wagner 2013 ’ / ‘AfriGa, specimen ID, 1901, specimen data documented, 9.1.2014 ’ ( NMPC). PARATYPES: 1 J 2 ♀♀, same data as holotype (2 ♀♀ in NMPC, 1 J in ZFMK).

Description. Body length: 3.4–4.0 mm (mean: 3.7 mm, holotype 3.5 mm) (n = 4).

Colouration. Labrum, labial and maxillary palpi brown or brownish-yellow; antennomeres I–VI (VII) yellow, becoming darker towards apex, following antennomeres brown and also darker towards apex. Head except for brown frontal tubercles, pronotum and elytron metallic green. Legs brownish-yellow or yellow; meso-, metathorax and abdomen entirely dark brown ( Fig. 5 ).

Sculpture and structures. Head. Antennomeres short, length ratio of second to third antennomere 0.78–0.86 (mean: 0.84), and length ratio of third to fourth antennomere 0.74–0.82 (mean: 0.78) ( Figs 1, 3 ). Eyes disk-like and widely separated ( Fig. 1 ), ratio of maximum eye width to interocular distance 0.44–0.45 (mean: 0.45).

Thorax. Pronotum coarsely and deeply punctated; trapezoidal; pronotal width 1.2–1.4 mm (mean: 1.25 mm), pronotal length 0.7–0.8 mm (mean: 0.73 mm), and pronotal length to width ratio 0.57–0.59 (mean: 0.58). Elytron coarsely and deeply punctated; elytral length 2.6–2.9 mm (mean: 2.73 mm), elytral width 1.7–2.1 mm (mean: 1.84 mm), and ratio of maximal width of both elytra to length of elytron 0.65–0.71 (mean: 0.67) ( Fig. 1 ). Metatibia less than double the length of basi-metatarsus; length ratio of basi-metatarsus to metatibia 0.40–0.42 (mean: 0.42) ( Fig. 4 ).

Abdomen. Male genitalia with short, slender, and parallel-sided median lobe; broad apically in dorsal view, and slightly down-curved in lateral view, with small sclerotised ventral projections alongside apical incision in ventral view ( Fig. 2a ); endophallic brush not protruding, basal orifice rectangular in ventral view; and dull.

Variability. The two females differ from males in colouration: they have head and pronotum completely pale brown ( Fig. 7 ). As many Neobarombiella species are extremely variable in colour (cf. BOLZ & WAGNER 2012), and because only four specimens of the new species are known, we cannot affirm the colour differences to the sexual dimorphism.

Differential diagnosis. Neobarombiella socotrana sp. nov. is characterized by deep, irregular punctation of the elytra; elongate trapezoidal pronotum; the length ratio of the second and third antennomeres, each about two-thirds of the following antennomere ( Fig. 4 ), and the distinct shape of the median lobe ( Fig. 2 ).

Nevertheless, there are some rather similar species of Neobarombiella from continental sub-Saharan Africa, namely N. nigrocaerulea (Jacoby, 1897) , N. nigrita (Jacoby, 1894) , N. punctata (Laboissière, 1920) , and N. punctatolineata (Jacoby, 1899) . Most are discernible by rather short second, and more elongate third, antennomeres (for comparison of the relevant ratios see Tab. 1); in N. socotrana sp. nov., the second antennomere is more than two-thirds of the length of the third antennomere. In N. socotrana sp. nov., the pronotum is also comparatively long, whilst being shorter in other similar Neobarombiella species. Neobarombiella nigrita has broader and more convex elytra; N. punctata is smaller in size; the eyes of N. nigrocaerulea are smaller with wider interocular distance; whereas N. punctata has larger eyes and smaller interocular distance. The median lobe of N. nigrocaerulea is more conical apically and has a broader incision when compared to the nearly parallel-sided median lobe of N. socotrana sp. nov., which has a broad apex and small medial incision.

Etymology. Named after Socotra Island; adjective.

Distribution. So far this species is only known from the type locality: Tudhen, Socotra, Yemen.

Figures

Figs 1–4. Neobarombiella socotrana sp. nov. 1 – habitus, schematic view; 2 – aedeagus (a – ventral view, b – dorsal view, c – lateral view); 3 – legs (a – prothoracic, b – mesothoracic, c – metathoracic); 4 – antennomeres I–IV of three different males (a, b, c) and one female (d). Scale bar = 1 mm.

Figs 5–7. Neobarombiella socotrana sp. nov. 5 – habitus of male holotype (3.5 mm); 6 – holotype labels; 7 – habitus of female paratype (3.8 mm).