Metallactus bezoar, Sassi, 2018

Sassi, Davide, 2018, Revision of the Metallactus kollari species-group with a new diagnosis of the genus (Coleoptera: Chrysomelidae: Cryptocephalinae), Zootaxa 4413 (1), pp. 57-110 : 101-103

Metallactus bezoar sp. nov.

( Figs 18 ; 24 )

Etymology. A bezoar is an object believed to have the power of a universal antidote against any poison. The name is here used to recall the young wizard Harry Potter, the main character of a popular series of fantasy novels. The word bezoar is a noun in the nominative singular, standing in apposition to the generic name (art. 11.9.1.2. I.C.Z.N., 4th edition).

Type material. HOLOTYPE: ♂, // “ Argentina Misiones ” [white label, printed] // “ XII-1941 H.L. Parker ” [white label, printed] // “ Metallactus bezoar sp. nov . HOLOTYPUS D. Sassi des.” [red label, printed] // ( NMPC). The holotype is the only specimen known so far .

Type locality. Misiones ( Argentina) .

Distribution. Argentina.

Diagnosis. A Metallactus of small size. The species belongs to the group with sub-conical pronotal outline and legs partly yellow. This group comprises also M. patagonicus , M. pollens , M. rileyi , M. dodecastictus . M. bezoar is easily distinguished from all these relatives by its small size. Among this group, only M. bezoar has elytral black pattern extended up to basal margin, which is totally black. Similar black elytral pattern is also seen in darkest forms of M. albipes and M. corruptus , but both differs in pronotal shape, weaker dorsal punctation and larger size. Aedeagal shape is also remarkably different. For size, dorsal punctation and general habitus the species strongly recalls M. affinis from which it can be distinguished by the different color pattern of fore tibiae, abdominal ventrites and dorsal surface, the less transverse outline of pronotum, the absence of apparent pronotal posterolateral impressions, the shorter interocular distance (in males). In M. bezoar the tip of aedeagal apex is more clearly curved than in M. affinis .

Description of male. Habitus in Fig. 18 a–b (HT). BL = 4.4 mm, BW = 2.7 mm, PL = 1.5 mm, PW = 2.4 mm. Interocular distance 11.0% of BL.

Head black with a X-shaped yellow spot extending on lower part of frons and clypeus. Surface rather densely micropunctured, dull, with few sparse short whitish setae denser on eye canthus and clypeus. Mid-cranial suture apparent, extended up to upper part of vertex. Punctation moderately impressed and scattered. First five antennomeres brownish, the subsequent totally darkened, dull and more diffusedly setose.

Pronotum yellow with a transverse subrectangular black stripe not reaching lateral margins, strongly and narrowly constricted on midline. Pronotal shape shortly tronco-conical with lateral margins thin, almost straight, barely visible from above. Posterolateral impressions poorly marked, in correspondence of which the posterior margins scarcely thickened. Surface moderately lustrous with scattered, well impressed punctation, slightly sparser and shallower on disc.

Scutellum completely black, distinctly raised, subsquared with truncated apex, almost bald with minute and sparse shallow punctures.

Elytra yellow with black pattern consisting of two large transverse bands and a pair of small elliptical spots on apex. First transversal band including basal margin and reaching lateral ones and epipleura. Second transversal band, just behind half of elytra, extending from suture up to lateral margins. Surface dull with sparse tiny transversal wrinkles. Punctation quite strong and dense, above all on anterior half of disc, partly arranged in almost regular striae fairly reduced and shallower on apical clivus. Intervals perceptibly raised.

Pygidium yellow with surface smooth, covered by sparse shallow punctures and pale setae.

Inferior parts of thorax almost completely black, only hypomera partly yellow on outer half. Abdominal visible ventrites 1–4 black on midline, extensively yellow on sides. Fifth abdominal ventrite completely yellow. Ventral surface covered by scattered yellowish setae, denser close to median line. Prothorax (prosternal process and hypomera) coarsely punctate; meso and metathorax almost impunctate. Prosternal process normally shaped, longitudinally grooved, apex blunt, surface covered with very long dense pale setae. Abdominal ventrites regularly and shallowly punctate. Legs yellow with tarsi and apex of tibiae darkened.

Fifth abdominal ventrite with a median depression moderately impressed, smooth, glabrous, impunctate and posterior margin weakly notched. Median lobe of aedeagus ( Fig. 18 c–e) with shortly triangular apex which is separated in ventral view from the aedeagal tube by two small but distinct lateral bulges including hairy dents. Ventral profile barely swollen in lateral view, apex fairly bent ventrally, hairy dents scarcely differentiated, bearing few scattered short whitish setae.

Endophallus ( Fig. 18 f–g) with sclerite I weakly sclerotized, large with denticle thin, blunt and straight. Dorsal spicule scarcely developed and poorly pigmented, flat, barely distinguishable. Sclerite II well developed, long, slender, clearly bent at base. Sclerite III rather squat with arch evenly thickened and apex bent downward. Branches of sclerite IV definitely longer than sclerite III in the folded up structure, slender, thin, fairly arched, evenly thickened, with rounded apex and surface fairly rugose.

Female unknown.

Figures

FIGURES 17–18. M. regalini (17), M. bezoar (18). 17a–b: habitus; 17c–e: median lobe of aedeagus in ventral (c), dorsal (d) and lateral (e) view [0.8 mm]; 17f: sclerites II–III–IV of endophallus [0.5 mm]; 17g: sclerite I and dorsal spicule of endophallus [0.4 mm]. 18a–b: habitus; 18c–e: median lobe of aedeagus in ventral (c), dorsal (d) and lateral (e) view [0.8 mm]; 18f: sclerites II–III–IV of endophallus [0.6 mm]; 18g: sclerite I and dorsal spicule of endophallus [0.5 mm]. 17a–b: holotype; 18a–b: holotype. hd: hairy dent: scI–IV: sclerites I–IV of endophallus; ds: dorsal spicule. Square brackets: length of scale segment.

FIGURES 20–28. Distribution maps for Metallactus kollari species-group. M. affinis (20); M. albifrons (21); M. albipes (22); M. bellatrix (23); M. bezoar (24); M. corruptus (25); M. dodecastictus (26); M. guarani (27); M. kollari (28). Grey squares: localities reported in a generic way.