Metallactus dodecastictus : Suffrian 1866
Creators: name: Sassi, Davide
Publisher: name: Zenodo
Year: 2018
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Chrysomelidae
Metallactus
Metallactus dodecastictus

description: Metallactus dodecastictus Suffrian, 1866
(Figs 11; 26)
Metallactus dodecastictus Suffrian, 1866: 355; Clavareau, 1913: 92; Blackwelder, 1946: 641.
Griburius nigritarsis Jacoby, 1907: 847; Clavareau, 1913: 90; Blackwelder, 1946: 640, n. syn.
Type material. Metallactus dodecastictus: Suffrian (1866) claimed that there was not any male specimen in the type series. I was able to track down the following material that fits in well with the data in the original description: 1♀ in BMNH, 1♀ in MNHUB; 4♀♀ in NMV. Once again, I would have liked to designate as lectotype a specimen in NMV, which possess the greatest number of syntypes. However, three specimens carry the indication: // “Trisanga [IIrisanga (= Orissanga)] Brasilien Natterer” // and one // “Ypanema Brasilien Natterer” //. Actually, Suffrian (1866) did not mention any specific localities and, above all, none of the specimens in NMV fits in well with the original description as regard the dorsal colour pattern. I am convinced that this lack of correspondence depends on a surplus of simplification adopted by Suffrian. In any case, in order to eliminate any source of ambiguity, I decided to designate the specimen in MNHUB as lectotype of the species. The typification has been made as follows. LECTOTYPE: ♀, pinned, // “23980” [white label, printed] // “ dodecastictus Suffr. * Brasil. Sellow” [blue label, handwritten] // “ Metallactus dodecastictus Suffrian, 1866 LECTOTYPUS D. Sassi des.” [red label, printed] // (MNHUB). PARALECTOTYPES: 1♀, pinned, // “Baly coll.” [white label, printed] // “Type Suffr Coll Baly” [white label, handwritten] // “ Metallactus 12 stictus Suffr Brazil ” [white label, handwritten] // (BMNH); 4♀♀, pinned, label data as detailed above [white label, printed] (NMV). All the paralectotypes have been labelled / / “ Metallactus dodecastictus Suffrian, 1866 Paralectotypus D. Sassi des.”[red label, printed] //.
Griburius nigritarsis: LECTOTYPE: ♀, glued, // “ Type ” [white with red border, printed] // “ S. Paulo ” [white label, handwritten] // “ Griburius nigritarsis Type Jac ” [blue label, handwritten] // “ Syntype ”[white with blue border, printed] // “Jacoby Coll. 1909-28 a” [white label, printed] // “ Griburius nigritarsis Jacoby, 1907 LECTOTYPUS D. Sassi des.” [red label, printed] // “ Metallactus dodecastictus Suffrian, D. Sassi det. 2016” [white label, partly handwritten] // (BNHM).
In my opinion, Griburius nigritarsis represents a slight chromatic variation of M. dodecastictus and should be synonymized with the latter.
Type locality. Metallactus dodecastictus: “ Brasilien ”. Griburius nigritarsis: São Paulo (Brazil)
Further material examined. BRAZIL: Goiás Jataí (2, USNMNH); Jatahy Etat de Gyaz Ch. Pujol 1895-96 (2, MNHN); Goiás Mineiro (1, NHMP); 10 km S Brasilia DF XII–II.1969 JM & BA Campbell (1, CNCI); São Paulo, Batatais XI.1945 G. Guérin (3, USNMNH).
Distribution. Brazil.
Diagnosis. A Metallactus of medium size. Suffrian (1866) stated that “it looks like a small M. patagonicus, more cylindrical and more vaulted, with a finer punctation”. As a matter of fact, the species belongs to the subgroup with subconical pronotal outline and legs at least partly yellow. This group comprises also M. patagonicus, M. pollens, M. rileyi and M. bezoar. M. londonpridei and M. longicornis are also similar in pronotal shape, but differs in having legs completely black. In M. dodecastictus elytral punctation is minute and denser than in the other species of this subgroup, with no remnants of striae in the anterior half of disc. Besides, when fully developed, black elytral pattern is arranged in 2+2+1, spots are smaller and more rounded than in the allied species. In addition, the second pair of spots is arranged obliquely, with the outer spot placed slightly forward than the inner one. In the other species of the group the two spots are placed on the same line. This tendency in the chromatic appearance should be verified on larger samples, but it turned out to be remarkably constant in the examined specimens. However, the black elytral pattern is strongly reduced to almost obliterated in some specimens. Antennae seem to be also characteristic in coloration, being almost completely infuscate when yellow pattern is fairly spread on first two-three antennomeres in the related species.
Description of female (male unknown). Habitus in Fig. 11 a–b (LT). BL = 5.8–6.0 mm, BW = 3.4–3.8 mm, PL = 1.8–2.0 mm, PW = 2.9–3.3 mm. Interocular distance 13.9–15.0% of BL.
Head yellow with vertex and upper part of frons black. Antennal insertion and upper part of ocular rim darkened. Frontal longitudinal groove yellowish. Surface dull with scattered rather strong punctures, denser on frons and clypeus, sparser and shallower on vertex. Mid-cranial suture barely evident. Setosity sparse, often few scattered whitish setae more apparent on clypeus, labrum and close to antennal insertions. Antennae with first five antennomeres brownish with lighter apex, the subsequent totally darkened, dull and more diffusedly setose.
Pronotum yellow with a pair of subelliptical black spots, slightly concave anteriorly, not reaching margins, sometimes reduced and somewhat different in shape. Pronotal surface subconical in shape with lateral margins narrow, almost regularly arcuate and maximum width behind half of length. Posterolateral impressions almost obliterated to barely detectable, so that posterior margin only faintly swollen on sides. Surface moderately lustrous with scattered, fairly impressed punctation, almost obliterated towards midline of disc.
Scutellum black, moderately raised, subsquared with truncated apex. Surface quite evenly and minutely punctured with sparse rather long whitish setae.
Elytra yellow with black pattern consisting of five rather small, rounded spots arranged in 2+2+1, none of which reaching margins or suture and with no tendency to coalesce transversally in the examined specimens. Anterior outer spot covering humerus. Outer spot of both pair placed slightly forward in respect of the inner one. In some specimens black elytral pattern missing with the exception of humeral spot. Surface dull with minute rather close punctation above all on anterior half. Relatively regular shallow striae apparent only on posterior half but almost obliterated on apical clivus. Intervals flat.
Pygidium completely yellow with smooth surface, covered by sparse weakly impressed small punctures and pale setae.
Inferior parts brownish to black with hypomera more or less extensively yellow. Lateral sides of abdominal sternites yellow as well. All ventral surface covered by scattered whitish rather long setae, regularly distributed except hypomera and sides of mesothorax. Punctuation regularly arranged and shallow, coarser on hypomera. Prosternal process longitudinally sunken, with sometimes a short feebly raised carena on apex. Prosternal surface covered with long dense pale setae. Legs yellow with tarsi and apex of tibiae black.
Fifth abdominal ventrite with rather deep, almost circular pit. Spermatheca (Fig. 11h) with upper and lower branches of vasculum, subequal in length. Lower branch uniform in thickness, faintly bent at base. Upper branch sometimes slightly swollen and then abruptly tapered in a short apex. Duct quite short, tightly coiled, coils apparent also in the last section. Insertion on bursa copulatrix hook-shaped, faintly to fairly pigmented. Rectal apparatus (Fig. 11 k–m) with dorsal sclerites slender, slightly tapered towards median line and apodemes large, hyaline. Ventral sclerite rather large, ribbon-like, deep, weakly tapered on sides, almost evenly pigmented, with apodemes rather large, fringed, moderately protruding.
description: Published as part of Sassi, Davide, 2018, Revision of the Metallactus kollari species-group with a new diagnosis of the genus (Coleoptera: Chrysomelidae: Cryptocephalinae), pp. 57-110 in Zootaxa 4413 (1) on pages 86-88, DOI: 10.11646/zootaxa.4413.1.2, http://zenodo.org/record/3066636