Griburella sanctaecrucis, Sassi, 2025

Sassi, Davide, 2025, A new genus of Pachybrachini from Bolivia (Coleoptera: Chrysomelidae: Cryptocephalinae), Zootaxa 5588 (3), pp. 455-464 : 460-462

Griburella sanctaecrucis sp. nov.

urn:lsid:zoobank.org:act:FFF67FEA-1B20-4C17-B691-2131AF864790

(Figs 3; 4e–g; 5c; 6c)

Types. HOLOTYPE: BOLIVIA: Santa Cruz Department: ♂, glued, median lobe of aedeagus glued on the same card, // “BOLIVIA Santa Cruz Dept. Florida pr. 1050–1150 m Refugio Los Volcanes 18°06’17’’S 63°35’55’’W beating of vegetation L. SEKERKA lgt. 19.xii.2014 ” [white label, printed] // “ Griburella sanctaecrucis gen. & sp. nov. HOLOTYPUS D. Sassi des.” [red label, printed] // ( NMPC). PARATYPES (3): 2♂, // “ BOLIVIA: SANTA CRUZ Res. Privada Potrerillos de Guendá ; -17°40.26-63°27.44; blacklight; 10–29/XI/2006; B.K. Dozier ” [white label, printed] // ( FSCA, DSPC); 1♀, // “ BOLIVIA: Santa Cruz, 3.7 km SSE Buena Vista, Hotel Flora & Fauna 405m 5– 15-XI-2001 17°29.949’S; 63°33.152’W M.C. Thomas & B.K. Dozier tropical transition forest [white label, printed] // ( FSCA). All paratypes also labelled // “ Griburella sanctaecrucis gen. & sp. nov. PARAYPUS D. Sassi des.” [red label, printed] // .

Type locality. Refugio Los Volcanes (Florida Prov., Santa Cruz Dept., Bolivia).

Distribution. Bolivia (Santa Cruz Dept.).

Etymology. The specific epithet is the latinized version of the name of the Bolivian department where the type locality is situated.

Diagnosis. The combination of characters—the slender body outline, the dark M-shaped elytral pattern on a yellowish background, the almost silky, matt appearance of the dorsal surfaces due to the unique arrangement of punctation and setosity, and the appendiculate claws—allows G. sanctaecrucis to be readily distinguished from other South American Pachybrachini species.

Description of male. Habitus in figs 1a–c (HT), 2b (PT). BL = 3.0– 3.1 mm, BW = 1.7 mm, PL = 0.9 mm, PW = 1.5–1.6. Antennal length (HT) = 2.8 mm. Ratio of antennomeres: 1.0; 0.5; 1.0; 1.3; 1.4; 1.5; 1.5; 1.5; 1.4; 1.4; 1.5.

Head: vertex and frontoclypeal surface chestnut with faint brownish hues. Labrum yellow with lower border lighter on sides. Basal half of mandibles chestnut, distal one dark brown. Setae on frontal surface longer and thicker along ocular rim and lower part of frontoclypeus. Mid-cranial suture faintly visible along lower part of vertex. Frontoclypeal sutures totally obliterated. Small, hollow, subtriangular pit with smooth, bare, moderately shiny surface on upper side of antennal socket, briefly extending along inner eye rim (op in fig. 3k). Antennae long, slender, reaching posterior elytral margin when bent backwards, inserted at about one third of ocular length from eye lower margin. First four basal antennomeres mostly chestnut with darker variegations, remainders totally blackish.

Pronotum: brownish with two curved yellow stripes extended from posterior to anterior margin, delimiting central third of pronotal surface. Anterior end of curved stripes blurred. Posterior pronotal margin mostly yellow as well. Posterolateral impressions well visible, oblique, delimiting narrow rear areas along posterior margin looking like slightly bulging, transverse furrows. Entire surface covered with dense, very fine punctation and short whitish setae.

Scutellum: chestnut, darker along margins. Surface dull, covered with coarse, shallow punctures.

Elytron: yellow with longitudinal darker pattern formed by large line developed along middle of elytron, starting just below anterior margin. Such stripe giving rise to two branches, first one almost straight, extending up to elytral clivus; second one, slenderer, forming an arch reaching suture and then reconnecting to first branch on clivus. Suture narrowly darkened as well. Further dark stripe on anterior third along suture. Finally, lateral margin largely darkened outside humeral tubercle, up to lateral clivus. Sometimes, elytral apex darkened too. Entire surface covered with short whitish setae and dense, uniform punctation, resulting in matt, almost spongy appearance. However, individual punctures, both in the dark patterned area and in the lighter parts, may be intensely blackened, suggesting traces of irregular striae.

Pygidium: totally yellow. Surface matt, covered with close, fine punctures and adpressed, pale setae.

Underside: ventral parts of thorax totally chestnut, only borders of abdominal ventrites yellowish. Median depression on fifth abdominal ventrite faint, hardly detectable. Ventrite posterior margin straight.

Legs: yellowish with distal tarsomeres at least partly darkened.

Male genitalia. Median lobe of aedeagus (Figs 1d–f) dorsoventrally flattened; in ventral view with sides gently sinuate along distal third so that maximum width just below apex. Apex sharp, triangular, straight in lateral view. Ventral surface marked with two deep longitudinal furrows along proximal half, externally delimited by sharp edge. Besides, two narrow drop-like depressions along apical sides, distally terminated by small but well-defined ridges just below apical tip. Setosity on sides limited to few long setae and few distinctly shorter ones. In dorsal view, apical foramen covered by two large, flat fraenula. Endophallus not examined.

Female. Habitus in figs 2a, 2c (PT). BL = 3.6 mm, BW = 2.0 mm, PL = 1.0 mm, PW = 1.8 mm. Interocular distance 2.8 % of BL.

In the only available female, the dorsal colouration is similar in pattern but lighter in colour shades. Besides, the interocular distance is broader and the antennae are shorter. Remarkably, although the eyes are more separated from each other than in males, the interocular distance is still unusually reduced in females, resulting in a distinctly 'masculine' appearance, which is quite peculiar among Pachybrachini .

The fifth abdominal ventrite in females has a quite large, rounded and deep pit. The bottom of the pit is glabrous, matt, impunctate but covered by tiny wrinkles. The vasculum of the spermatheca (Fig. 3e) is scarcely pigmented with a straight proximal lobe not swollen at base; the distal lobe is longer than the proximal, regularly curved, with a pointed apex bent downwards. The ampulla is not pigmented, sitting at the end of the proximal lobe. The duct insertion and the sperm gland insertion are widely separated. The duct is uniform in size (evenly thickened), slender, straight, i. e. not coiled. The insertion on the bursa copulatrix is simple, i. e. neither swollen nor pigmented. Figures 3f–h provide a comparative overview of the spermatheca among the type species of the genera: f: Griburius ( G. scutellaris ), g: Pachybrachis ( P. hieroglyphicus ) h: Metallactus ( M. kollari ).