Madecorformica silhouetta, Bellamy, 2008

Bellamy, C. L., 2008, A new monotypic genus of ant-mimicking Coraebini (Coleoptera: Buprestidae: Agrilinae) from Madagascar, Zootaxa 1817 (1), pp. 65-68 : 66-67

Madecorformica silhouetta , sp. nov.

( Figures 1–6 )

Description of male holotype. Myrmecomorphic; small (7.0 mm maximum length x 2.3 mm width across apical 1/3 of elytra), elongate-ovoid, subcylindrical; integument generally black with elytra bearing a mix of short erect setae, both black and off-white, forming a pattern resembling a silhouette of one pair of inverse facing heads ( Fig. 5a, b ); posterior portion of metaventrite and metepiventrite a deep iridescent maroon; underside with short, appressed squamose setae most dense on thoracic ventrites; head with frontovertex broad, flat on vertex; frons with short, shallow longitudinal depression between eyes; eyes large, inner margins diverging dorsally; circumocular groove extends from beyond dorsalmost point along inner margin to beyond ventral-most point; bisinuate supra-antennal groove above large antennal cavities; antennal cavities narrowly separated; clypeal margin broadly, deeply, arcuately emarginate; gena with feeble transverse depression for basal antennomeres in repose; distal margin of gena broadly rounded; antennae with scape narrow, elongate, feebly arcuate, nearly as long as 2+3+4 together, triangularly serrate from antennomere 5; right antennae missing antennomeres 10–11; pronotum 1.7 times wider than long, widest near midpoint, narrowing to posterior margin; anterior margin feebly convex; posterior margin bisinuate on either side of prescutellar lobe; disc transversely convex on anterior 1/2, otherwise flattened posteriorly and laterally; lateral margin entire; one elongate, narrow premarginal carina on either side parallel to margin; scutellum elongate cordiform; elytra much wider both across humeri and again at about apical 1/3; humeri strongly, subangularly elevated, with angled peaks slightly diverging from each other; disc evenly, transversely convex; lateral margin narrowing posterior to margin below humeral swelling, before widening at about mid-point then narrowing again from apical 1/3 to narrowly, separately rounded apices; epipleuron extends along entire length, widest below humerus, subparallel to opposite metacoxa, then much narrower and extending to apex; pygidium not visible beyond elytra, with apical margin entire; proventrite with mentonniere very feebly produced, angularly bilobed; disc evenly transversely convex; process broad, subparallel between procoxae, apex feebly trilobed; abdominal ventrites expanded laterally, ventrite 2 wider than 1 or 3–5, widest medially; ventrite 5 entire, without terminal sexual morphology; legs with tibiae flattened, having arcuate outer edge; tarsi with tarsomeres 1–4 with at least partial ventral pulvilli; tarsal claws appendiculate; aedeagus as in Fig. 6 .

Variation. In the short type series, the variation is only in size and proportion. Males vary: 6.2–7.3 x 2.1–2.3 mm; females vary: 6.8–8.2 x 2.4–3.0 mm. The pair of silhouettes on the elytra vary slightly, allowing the imagination to consider that these may look like the head of a baboon or a chameleon, etc. (e.g. Figs. 1, 5a, b ).

Specimens examined. Holotype ♂ ( MNHN): Madagascar Est., Distr. Mananara N., Seranambe, II-[19]64, Vadon et Peyrieras; 13 paratypes: 8, same data as holotype, except 1 ♀, I-[19]64; 3 ♂♂, 1 ♀, II-[19]65; 1 ♂, 2 ♀♀, without date; 1 ♂, Antanambe, II-[19]67; 2 ♂♂, 2 ♀♀, Mont Antampona, iii-[19]67 . Paratypes deposited in MNHN, NMPC and CLBC .

Etymology. The specific epithet silhouetta is chosen for the elytral pattern of facing heads on the disc.

Remarks. This new species differs, and can be distinguished, from other lookalike, putative ant-mimics of the genus Entomogaster as noted in Table 1.

Figures

FIGURES 1–6. Madecorformica silhouetta, gen. & sp. nov. Fig. 1, holotype, dorsal habitus; Fig. 2, holotype, lateral habitus; Fig. 3, closeup of humerus; Fig. 4, holotype, ventral habitus; Figs. 5a, b, elytral silhouette, inverted dorsal aspect; Fig. 6, aedeagus. Scale bars = 1.0 mm; scale equal for Figs. 1, 2, 4.