Griburius sciurellus ( Suffrian, 1866 )

Sassi, Davide, 2024, Revision of the Griburius posticatus (Suffrian, 1866) species group (Coleoptera: Chrysomelidae: Cryptocephalinae), Zootaxa 5406 (2), pp. 201-237 : 220-221

Griburius sciurellus ( Suffrian, 1866)

(Figs 6; 13a)

Scolochrus sciurellus Suffrian, 1866: 105 ; 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 sciurellus , but he reported he was able to examine only males from two distinct collections. A single syntype was found in BMNH. The typification was made as follows. LECTOTYPE: (BMNH) ♂, glued, aedeagus and detached abdomen glued on the same label bearing the specimen // “Brasilia” [green label, handwritten] // “Type Suffrian Coll Deyrolle” [white label, handwritten] // “Baly Coll.” [white label, printed] // “ Scolochrus sciurellus Suffr Brazil ” [recto], “Type coll: Deyrolle” [verso] [white label, handwritten] // “ Griburius sciurellus ( Suffrian, 1866) ( Scolochrus sciurellus ) LECTOTYPUS D. Sassi des.” [red label, printed] //.

Type locality. “ Brazil ” .

Additional material examined. BRAZIL: Minas Gerais: Serra do Caraça “2° semestre 1884” (1, MNHN); UFMG Campus Pampulla 19°52’ S 43°58’ W 830 m Malaise 28.XI.1996 (2, TAMU & DSPC) .

Distribution. Brazil (Minas Gerais).

Diagnosis. The dorsal and leg coloration of the examined specimens, entirely yellowish (although the pronotum and legs may sometimes be darker but never distinctly black), resemble that of some particularly light-coloured variants of G. ephippiatus and G. hyacinthinus . However, G. sciurellus is easily distinguishable for its notably slender outline. Additionally, the body is typically cylindrical, whereas the dorsal surface is flattened in G. ephippiatus , and the elytral lateral margins run parallel and do not converge towards apex as in G. hyacinthinus . Finally, the characteristic thickening of the anterior tarsi, which is present in males of other species in the group when known, is absent.

Description of male (female unknown). Habitus in figs 6a–b (LT). BL = 4.5– 4.7 mm, BW = 3.0 mm, PL = 1.6–1.8 mm, PW = 2.6–2.8 mm. Interocular distance 8.5–8.9 % of BL.

Head totally yellow. Vertex and frons glabrous, almost impunctate, only an irregular row of shallow punctures along the ocular rim. Frontoclypeal suture and clypeal surface marked with sparse shallow setigerous punctures. Mid-cranial suture short, well impressed in the middle of frons. Ocular lines narrow, strictly adhering to ocular rim. Ocular canthus rounded, shallowly punctured with short, appressed setae. First five antennomeres bright, yellowish, 3–5 subcylindrical, the 6–11 darkened, dull, more flattened and more diffusedly setose.

Pronotum entirely yellow to brownish. Pronotal shape shortly tronco-conical. Lateral margins thin, almost not visible in dorsal view, evenly curved with maximum width close to posterior margin. Posterolateral impressions obliterated. Surface scarcely flattened, shiny with scattered weak punctation.

Scutellum yellow to chestnut, distinctly raised, finely setose and minutely punctured.Apex truncated in straight line.

Elytron totally yellow. Epipleuron equally coloured. Elytral outline parallel-sided. Elytron disc weakly flattened on posterior part. Lateral margin narrow, barely visible in dorsal view. Scutellar area weakly raised. Humeral callus prominent, impunctate. Elytral surface with fine but well impressed punctures arranged in irregular rows, visible on elytral apex too. Punctures rather confused in anterior inner part of disc. Intervals flat. Epipleuron smooth, impunctate, with plane surface.

Pygidium yellowish, smooth, covered with sparse shallow punctures and whitish setae.

Inferior parts of thorax light brown. Hypomera, mesepimera and mesepisterna almost glabrous, smooth and rather shiny. Metepisterna and metasternum very shallowly punctate, covered with dense appressed setae. Prosternal process rather large with scarcely curved sides, longitudinally grooved, coarsely punctured with long setae and large triangular apex.

Abdominal ventrites completely brownish, shallowly and sparsely punctured, with dense recumbent setae. Legs yellow to brownish with slightly darker tarsi.

Median depression on fifth abdominal ventrite short, transverse and shallow, hardly distinguishable from remainder of ventrite surface. Posterior margin of fifth abdominal ventrite weakly notched at middle. Median lobe of aedeagus (Figs 6g –k) parallel-sided, dorso-ventrally flattened. Apex with concave sides, terminated by triangular denticle. In lateral view apex slightly bent ventrally. Setose depressions shallow, bearing setae only along external margins, barely separated from glabrous depressions due to lack of distinct partition septum. Aedeagal ventral surface with slender carina extended from apex down to edge of tegminal ring.