Griburius semiluteus ( Suffrian, 1866 )

Sassi, Davide, 2024, Revision of the Griburius posticatus (Suffrian, 1866) species group (Coleoptera: Chrysomelidae: Cryptocephalinae), Zootaxa 5406 (2), pp. 201-237 : 221-223

Griburius semiluteus ( Suffrian, 1866)

(Figs 7; 12d)

Scolochrus semiluteus Suffrian, 1866: 114 ; Clavareau, 1913: 91 [ Griburius ] (catalogue); Blackwelder, 1946: 640 [ Griburius ] (catalogue).

Types. Suffrian (1866) did not mention the number of the specimens available for the description of Griburius semiluteus , but he reported he was able to examine both male and female specimens of the species. It was possible to trace down one syntype in MNHUB, two in BMNH, and one in NMV. The typification was made as follows, in order to stabilize the epithet. LECTOTYPE (by present designation): (BMNH), ♂, pinned // “Type Suffr. Coll. Deyrolle” [white label, handwritten] // “ Scolochrus semiluteus Suffr. Brazil ” [recto] “Type Suffr Coll Deyrolle” [verso] [white label, handwritten] // “Baly Coll. [White label, printed] // “ Griburius semiluteus ( Suffrian, 1866) ( Scolochrus semiluteus ) LECTOTYPUS D. Sassi des.” [red label, printed] //. PARALECTOTYPES (3) were designated as follows. (BMNH) 1♂, glued, median lobe of aedeagus and abdomen glued on separate cards // “Minas Geraes” [White label, handwritten] // “I” [Blue label, handwritten] // “67 56.” [White label, printed] // “TYPE.” [White label, printed] // “semiluteus m” [Blue label, handwritten] //; (NMV) 1♀, pinned // “Trisanga Brasilien Natterer” [White label, printed] //; (MNHUB) 1♂, pinned // “24017” [white label, printed] // “semiluteus Suffr * Brasil. v. Olf.” [blue label, handwritten] //. The label information and the number of syntypes for the MNHUB paralectotype matches the registration data from the old catalogue of the MNHUB (“24017. semiluteus Suffr. *. 1. – [ Brasil], v. Olf.”. All paralectotypes were labelled: // “ Griburius semiluteus ( Suffrian, 1866) ( Scolochrus semiluteus ) PARALECTOTYPUS D. Sassi des.” [red label, printed] //.

Type locality. Minas Gerais (Brazil).

Additional material examined. In BMHN a female specimen collected in Minas Gerais is also preserved, but there is not sufficient evidence to consider it as part of the type series .

Distribution. Brazil (Minas Gerais, São Paulo).

Diagnosis. The species most closely resembling G. semiluteus in external features is G. ephippiatus , with which it shares a certain flatness of the pronotal and elytral discs. However, the distinctive dorsal coloration appears sufficient to easily distinguish between the two species. Nevertheless, it is possible that a comparison involving a hopefully larger number of specimens, in contrast to the few available for this study, could reveal chromatic variants that are less distinct.

Description of male. Habitus in figs 7a–b (LT). BL = 5.0– 5.6 mm, BW = 3.2–3.7 mm, PL = 1.6 mm, PW = 3.0– 3.3 mm. Interocular distance 10.0–10.7 % of BL.

Head totally black. Labrum dark brownish. Vertex and frontoclypeal surface with sparse setae and well impressed punctation, denser along ocular margins and on lower part of frontoclypeal surface. Mid-cranial suture slender but detectable from vertex to frontoclypeal suture. Upper lobes of eyes strongly separated from each other. Ocular lines narrow, strictly adhering to ocular rim. Ocular canthus rounded, with surface almost hidden by short, dense, appressed whitish setosity. Antennae normal in shape, first five antennomeres yellowish, bright, 3–5 subcylindrical, the subsequent ones gradually darker, dull, moderately flattened and more diffusedly setose.

Pronotum totally ochraceous. Pronotal shape trapezoidal, rather short. Lateral margins narrow, barely visible from above, slightly angulate behind midline with maximum width behind half length. Posterolateral impressions shallow, short, barely perceptible. Surface fairly flattened, with well impressed, sparse punctation, denser along sides of disc.

Scutellum brownish bordered with black, moderately raised, with apex truncated in a straight line, finely setose and scarcely punctured.

Elytron surface black with ochraceous band covering basal fourth of surface. Such band slightly more extended along lateral margin to cover whole epipleuron. Elytral outline lengthened, slightly flattened with almost parallel sides. Lateral margins rather narrow, barely visible simultaneously from above. Scutellar area slightly raised. Humeral callus prominent, impunctate. Surface with fine punctation arranged in irregular rows, barely visible on clivus. Epipleuron surface slightly convex, smooth, impunctate.

Pygidium dark brown, covered with appressed, whitish setae.

Hypomera mostly ochraceous, shiny, bare, basically devoid of punctures. Prosternal process ochraceous as well. Remainder of inferior parts of thorax and abdomen brownish with surface covered by dense, short, appressed silvery setae. Prosternal process wide, almost flat with parallel sides and short, triangular apex on same line with remainder of surface. Surface coarsely punctured with sparse, semi-erect setae. Legs totally black. Anterior tarsi short and squat.

Median depression on fifth abdominal ventrite shallow and barely distinguishable from remainder of ventrite surface. Posterior margin of fifth abdominal ventrite almost straight.

Median lobe of aedeagus (Figs 7h–m) in lateral view almost cylindrical along basal half, then markedly tapered toward apex. Apex short, triangular in ventral view. Setose depressions narrow, shifted on sides, setose only along margins. Aedeagal ventral surface with long, sharp, median carina and two rounded depressions just below apex.

Female. The only females available for the study are figured in Figs 7f and 7g. Unfortunately, it was not possible to study the specimens in detail. For this reason, the morphology of the spermatheca is not known. Still, the colour pattern matches well with that of the male, and the specimen differs in the slenderer shape of the anterior tarsi.