Griburius hyacinthinus ( Erichson, 1848 )

Sassi, Davide, 2024, Revision of the Griburius posticatus (Suffrian, 1866) species group (Coleoptera: Chrysomelidae: Cryptocephalinae), Zootaxa 5406 (2), pp. 201-237 : 210-212

Griburius hyacinthinus ( Erichson, 1848)

(Figs 3; 11c; 12b)

Pachybrachis hyacinthinus Erichson, 1848: 577 ; Suffrian, 1866: 116 [ Scolochrus ] (taxonomic notes); Clavareau, 1913: 90 [ Griburius ] (catalogue); Blackwelder, 1946: 640 [ Griburius ] (catalogue).

= Scolochrus fragrans Suffrian, 1866: 71 ; Clavareau, 1913: 89 [ Griburius ] (catalogue); Blackwelder, 1946: 640 [ Griburius ] (catalogue). Syn. nov.

Types. A single type is hosted in MNHUB. Strangely enough, Eduard Suffrian, who redescribed the species in his 1866 monograph, wrote that the specimen was badly damaged, while it seems to be in quite good condition. Nevertheless, the label data leave no doubt that it is a type. Erichson did not mention the number of the studied specimens, but the information registered on the old catalogue of the MNHUB (“24012. hyacinthinus Erichs. * 1. Brit. Guyan., Schomb.”) and the statement by Suffrian (“I only have the only one specimen of this species described by Erichson...”) lead me to believe that the specimen must be considered the holotype. The holotype is identified as follows. HOLOTYPE (by present designation): (MNHUB) ♂, pinned // “24012” [white label, printed] // “ Guyana Schomb.” [white label, handwritten] // “hyacinthinus Er. [blue label, handwritten] // “ Griburius hyacinthinus ( Erichson, 1848) ( Pachybrachis hyacinthinus ) HOLOTYPUS D. Sassi det.” [red label, printed].

Regarding Griburius fragrans, Suffrian (1866) did not mention the number of specimens under study, but he reported SMNH and “Mus. Clark” (now in BMNH) as depositories of the studied material. Moreover, he reported the collector’s name (“von Dupuizet gesammelt”) and the “Cayenne” for the specimens housed in SMNH and stated that all the specimens were female. I was able to track down three specimens that fully matches the information given by Suffrian. The typification has been made as follows, in order to stabilize the epithet. LECTOTYPE (by present designation): (SMNH) ♀, pinned // “Cayen” [white label, printed] // “Dupui-zet” [white label, printed] // NHRS-GULI 000060971” [white label, printed] // “ Griburius fragrans ( Suffrian, 1866) ( Scolochrus fragrans ) LECTOTYPE D. Sassi des.” [red label, printed] // “ Griburius hyacinthinus Suffr. D. Sassi det. 2023” [white label, printed] //. PARALECTOTYPES: (SMNH) ♀, pinned, same data of the LT // “NHRS-GULI 000060972” [white label, printed] //; (BMNH) ♀, pinned // “fragrans ” [blue label, handwritten] // “E. Coll. Laferté” [white label, printed] // “67.56” [white label, printed] // “Sericogaster [unreadable word] Cayenne” [white label, handwritten] // “Type” [white label, printed] // “4” [blue label, handwritten] // “ Syntype ” [round white label with blue border, printed] //. Both paralectotypes with the following labels: // “ Griburius fragrans ( Suffrian, 1866) ( Scolochrus fragrans ) PARALECTOTYPUS D. Sassi des.” [red label, printed] // “ Griburius hyacinthinus Suffr. D. Sassi det. 2023” [white label, printed] //. A careful comparison of genitalia and the external morphological characters of the available specimens attributable either to G. hyacintinus or to G. fragrans on the basis of the dorsal colour pattern, did not show any traits allowing to keep the distinction at species level. For this reason, the following synonymy is here proposed: Griburius hyacinthinus ( Erichson, 1848) = Griburius fragrans ( Suffrian, 1866) syn. nov.

Type locality. G. hyacinthinus : Guyana. G. fragrans : French Guiana.

Additional material examined. BRAZIL: Amazonas: Massanary Hahnel (1, MNHN) ; “Amazonas” Bates (2, BMNH) . Pará: Santarém M. de Mathan I.1878 (1, USNMNH) ; Óbidos Hahnel 1880 (3, MNHN) . COLOMBIA: Caquetá: Yuruyaco 73k SW Florencia 5.II.1979 (1, BMNH) . FRENCH GUIANA: Saint-Laurent-du-Maroni: Saint-Laurent-du-Maroni 1862 (2, MNHN) . Saint-Georges Arr.: Gourdonville Riviére de Kourou (1, NMPC) . “Cayenne” (1, MNHN) .

Distribution. Brazil (Amazonas, Pará), Colombia, French Guiana, Guyana. New to Brazil and Colombia.

Diagnosis. The species can be distinguished from others in the group by its barrel-like shape and the evident metallic hues on the dorsal surface. Additionally, the elytral punctures are very fine and arranged in nine almost regular rows with intervals densely covered by micropunctures, whose dimensions are sometimes only slightly smaller than those of the aligned points. In this case, the elytral surface may appear covered with a dense network of very fine points irregularly distributed. Furthermore, the wide interocular distance, even in males, can be useful for identification. The dense golden-yellow ventral setae are also characteristic, but in some specimens, they may appear less conspicuous, likely due to the preparation and preservation conditions of the specimens.

Description of male. Habitus in figs 3a–b (HT). BL = 5,8– 6.1 mm, BW = 3.8–4.0 mm, PL = 2.1–2.2 mm, PW = 3.9–4.0 mm. Interocular distance 13.1–13.8 % of BL.

Head metallic blue with vague violet reflections. Labrum yellow to dark brownish. Vertex and frons with surface slightly convex without clue of mid-cranial and frontoclypeal sutures, smooth, almost bare, with few very shallow, scattered punctures, denser between lower half of eyes. Clypeal area transversely rugulose with short, scattered setae. Upper lobes of eyes strongly separated along median lines. Ocular lines narrow, strictly adhering to ocular rim. Ocular canthus angular, with surface almost hidden by dense, appressed setosity. Antennae rather short, blackish with antennomeres 3–5 bright, subcylindrical, subsequent ones dull, moderately flattened and more diffusedly setose. Mandibles strongly developed.

Pronotum reddish or metallic blue with marked violet reflections. Pronotal shape elliptical, rather short. Lateral margins narrow, barely visible from above along anterior half, regularly curved with maximum width just at half length. Posterolateral impressions short but easily perceptible, in correspondence of which posterior margin appears thickened and slightly salient. Surface vaulted, regularly convex, with rather close, two-sized punctation (namely moderate punctation mixed up with finer punctures).

Scutellum black, dull, distinctly raised, finely setose and minutely punctured. Apex truncated in straight line.

Elytron surface metallic blue with marked violet reflections. Elytral outline squat, convex with sides mildly convergent toward apex, Lateral margins rather narrow, barely visible simultaneously from above. Scutellar area perceptibly raised. Humeral callus prominent, impunctate. Surface with rather fine, dense, two-sized punctation (similar to pronotal one), rather confusedly arranged on the whole surface. Epipleuron surface plane, shiny, smooth.

Pygidium yellow, covered with sparse shallow punctures and rather dense, golden setae.

Hypomera same color of pronotum (reddish or metallic blue), shiny, almost bare and impunctate. Prosternal process yellowish. Mesepimera and mesepisterna light brown, almost impunctate, partially covered with scattered, short golden setae. Surface of metepisterna, metasternum and abdominal ventrites often totally hidden by dense recumbent golden setae. Prosternal process wide, almost flat with parallel sides slightly and short subtriangular apex. Surface coarsely punctured with sparse, semi-erect setae. Anterior legs metallic dark blue with yellow coxae. Median and posterior ones light brown, with dark mesotibiae and mesotarsi. Often legs totally blackish except for yellowish coxae. Tibiae strongly arcuated. 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 weakly notched at middle.

Median lobe of aedeagus (Figs 3m –p) terminated with acute, almost straight triangular apex. Setose depressions narrow, shifted on sides, setose only along apical part of distal margins. Aedeagal ventral surface with long, sharp, median carina and two deep glabrous depressions just below apex.

Female. BL = 5.9–6.3 mm, BW = 4.1–4.2 mm, PL = 2.0 mm, PW = 3.9–4.2 mm. Interocular distance 15.3–15.9 % of BL.

Female differs in the larger interocular distance, in the reduced and finer punctation on the frontoclypeal surface; in the pronotal shape, tronco-conical rather than elliptical with maximum width at base and not at midline. Additionally, often the golden setosity is not as gaudy as in male and does not hide the surface of inferior parts, and anterior tarsi are narrower. A single female from Massanary (= Maçauary, = Macauari, 4°8’ S, 57° 35’ W, Amazon) is totally chestnut with the exception of the blackish head surface.

Fifth abdominal ventrite in females with quite large, almost circular, moderately deep pit. Bottom of pit bald, matt, impunctate but covered by tiny wrinkles. Vasculum of spermatheca (Fig. 11c) scarcely pigmented, sometimes mildly twisted around a longitudinal axis (namely, not laying on a plane), with slender proximal lobe strongly bent at base. The distal lobe is slender as well, long, regularly curved, with a sharp apex bent downward. The ampulla is short, not pigmented. The duct insertion and sperm gland insertion are barely separate. The duct is rather short, not coiled, slightly more robust in proximity of the bursa copulatrix. The insertion on bursa copulatrix is simple, not pigmented.