Griburius scutellaris (Fabricius, 1801)

Sassi, Davide, 2023, Revision of the Griburius scutellaris (Fabricius, 1801) species group (Coleoptera: Chrysomelidae: Cryptocephalinae), Zootaxa 5315 (6), pp. 501-548 : 506-507

publication ID	https://doi.org/ 10.11646/zootaxa.5315.6.1
publication LSID	lsid:zoobank.org:pub:33189294-DC74-4CFA-8213-2600B8459040
DOI	https://doi.org/10.5281/zenodo.8147485
persistent identifier	https://treatment.plazi.org/id/546A6413-FFA8-FF9A-FF5F-F9BAFA15F96A
treatment provided by	Plazi
scientific name	Griburius scutellaris
status

Treatment

Key to species of the Griburius scutellaris species group

In the following key some dorsal colour patterns are emphasized in the species identification process, but it should be borne in mind that the coloration is extremely variable within the species group, and intermediate specimens and outliers are rather common. For this reason, the shape of the aedeagal median lobe must always be studied for a reliable identification (also check the diagnoses given for each species).

1. Legs mostly black or dark brown, in particular the anterior ones................................................ 2

-. Legs without distinct dark pattern, above all the anterior ones; generally, legs are totally yellow, at most with some light brown patches. If patches on legs are rather dark, then elytron with single large black marking with curved external margin ( Fig. 4 View FIGURE 4 ) or the dorsal surface is entirely brown ( Fig. 6 a–b View FIGURE 6 )............................................................. 5

2. At least base of pronotum broadly brick red, anterior half predominantly black with white or whtish anterior border or sometimes the surface of the pronotum is entirely reddish. Elytron mostly black with a large pale yellow sutural stripe (typical colour), sometimes only the anterior inner half of elytron occupied by a pale sutural spot (“ cazicus form”), in further cases elytron is predominantly pale with black apical half (“ suffrian form”). In males the upper lobes of the eyes are nearly in contact along the median line......................................................................... G. montezuma ( Fig. 9 View FIGURE 9 )

-. Dorsal chromatic pattern differently arranged. In males the upper lobes of the eyes are either almost in contact along median line or distinctly separated.............................................................................. 3

3. In males, the upper lobes of eyes are distinctly separated by a narrow dark strip of frons. In females, the frontoclypeal area is black with a transverse yellow line, often wavy and/or interrupted, between the ocular canthi. Middle and hind legs generally with yellow patches................................................................................... 4

-. In males, the upper lobes of eyes are virtually in contact along median line. In females, the frontoclypeal area is mostly yellow. Legs totally black or dark brown........................................................... G. lecontii ( Fig. 8 View FIGURE 8 )

4. Pronotal punctation generally light, not homogeneously distributed, deeper on the sides and near posterior margin, obliterated or almost obliterated at middle of disc..................................................... G. albilabris ( Fig. 2 View FIGURE 2 )

-. Pronotal punctation deeper and coarser, regularly distributed including the middle of disc.......... G. biverrucatus ( Fig. 3 View FIGURE 3 )

5. Elytron yellow or reddish with a single large black spot with curved external margin leaving free (yellow) the side of disc, the elytral apex and the scutellar area. Sometimes there is a further little yellow spot behind midline near the suture ( Fig. 4a View FIGURE 4 )........................................................................................ G. boucardi ( Fig. 4 View FIGURE 4 )

-. Elytral chromatic pattern differently arranged, being elytral surface unicolour or with more than a single large black spot... 6

6. Pygidium completely yellow, sometimes with a slightly darker central area, but never with black spots................. 7

-. Pygidium with more or less extended black patch........................................... G. scutellaris ( Fig. 11 View FIGURE 11 )

7. Dorsal colour pattern generally devoid of black spots, if pattern is present, the spots are usually brown or dark brown, never definitively black ( Fig. 6e–f View FIGURE 6 ). The most common pattern is, however, uniform yellow up to uniform dark brown, sometimes with some contrast between elytra and pronotum. The pronotum is usually immaculate or, rarely, with a remnant of two washedout spots. The abdomen is often quite uniformly yellowish, at times the central part of the ventrites is darkened, but generally not definitively black. In the female the frons is completely yellow. Species from the Yucatán Peninsula and neighbouring regions................................................................................ G. errans ( Fig. 6 View FIGURE 6 )

-. Typical dorsal colour pattern arranged as follows: the pronotum is yellow with two more or less extended black spots on the disc; elytron are yellow as well with 4 black spots, two along the basal margin, one on the suture, approximately at midline, the fourth in the middle of the elytron, just before the apical slope. At times a fifth spot on the suture, aligned with the fourth one. These spots can variously extend and merge with each other or be very small to completely missing. In the female the frons is always black with yellow “eyebrows” and a transversal line between the ocular canthi also yellow. The abdominal ventrites are typically black in the middle............................................................................ 8

8. Dorsal black spots generally small, rounded, rarely fused together, often punctiform or absent on the pronotum. Elytral sutural spots often absent. In specimens from Dade and Monroe counties, however, sometimes more extensive and partly fused dorsal black spots have been observed. Species from Florida and neighbouring territories................... G. larvatus ( Fig. 7 View FIGURE 7 )

-. Dorsal black spots generally larger, at times with a clear tendency to transverse fusions. The spots on the pronotum are longitudinally elongated, drop-shaped or arcuate. On the elytron there is often an additional fifth black spot ( Fig. 10e View FIGURE 10 ) on the elytral suture, aligned with the fourth spot.................................................................. 9

9. Dorsal black pattern more developed. Pronotal spots almost always reaching anterior margin, often touching the posterior margin as well, leaving only a flask-shaped light area at the middle of disc. Black spots along basal margin of each elytron often fused to form a transverse band. On the posterior half of the elytron the black spots are often fused to form a transverse band as well................................................................................ G. decoratus ( Fig. 5 View FIGURE 5 )

-. Dorsal black pattern generally less developed. Pronotal spots usually drop-shaped, never reaching both the anterior and posterior margins. Elytral black spots on each elytron usually not fused to each other, giving a typical 4 + 1 + 3 pattern on the total area of elytra................................................................................ G. rileyi ( Fig. 10 View FIGURE 10 )