Pachybrachis viduatus

Riley, Edward G. & Barney, Robert J., 2015, Definition And Revision Of The Viduatus Species- Group Of North American Pachybrachis Chevrolat (Coleoptera: Chrysomelidae: Cryptocephalinae), The Coleopterists Bulletin 69 (1), pp. 25-59 : 29

Pachybrachis viduatus species-group

Group Diagnosis. Moderate to large species, length (2.35–3.63 mm); dorsum glabrous with dark coloration black, usually extensive; color patterns distinctive, fairly stable as maculae or vittae; eyes of both male and female widely separated (0.36–0.69 mm); front without ocular lines; antennae exceptionally long and slender, attaining or surpassing declivity in males; terminal antennomere linear; protarsal claws of male not enlarged; anterior femora swollen; anterior tibia unmodified, with apical spur absent or so greatly reduced as to appear absent. Median lobe of male genitalia with median basal plate simple; en-face outline with apicolateral margin broadly and evenly rounded to abruptly rounded; nodule absent to distinct, narrowly to broadly triangular when distinct; ventral surface of shaft flattened, inflated, with or without distinct keel; beard setae short in patch or in wisp; penicilli absent.

Remarks. We propose this species-group to include five named Nearctic species, P. m-nigrum , P. picturatus (Germar) , P. pulvinatus Suffrian , P. trinotatus (Melsheimer) , and P. viduatus , and the four new species presented below. Within the Nearctic Pachybrachis fauna, the lack of an apical spur on the anterior tibia appears to be a unique synapomorphy for the group.

The nine species that comprise the viduatus species-group are divided into three species complexes, each consisting of species that are similar in external appearance:

P. m-nigrum complex: dorsum with pale yellow and black patch-work pattern ( Figs. 4–6 ).

1. P. deceptor Riley and Barney , new species 2. P. m-nigrum (Melsheimer)

P. trinotatus complex: dorsum mostly black (rarely not), with reddish or yellowish pronotal maculae ( Figs. 12–14 ).

3. P. pulvinatus Suffrian

4. P. trinotatus (Melsheimer)

P. viduatus complex: dorsum yellowish, elytra with heavy, black vittae ( Figs. 7 , 15–18 ).

5. P. bloxham Riley and Barney , new species 6. P. chester Riley and Barney , new species 7. P. kentuckyensis Riley and Barney , new species 8. P. picturatus (Germar)

9. P. viduatus (F.)

Biology. Almost nothing is known of the biology of the members of the viduatus species-group. Adults have been associated with various plants, summarized in Clark et al. (2004) or newly reported below under each species. The plant genus Hypericum L. ( Clusiaceae ) is a confirmed adult association and probably the adult food plant for five included species, and it is a suspected plant association for a sixth species. Larvae and larval habits are unknown.

Figures

Figs. 4–7. Pachybrachis species, dorsal and lateral habitus, face, and pygidium. 4) P. m-nigrum, lectotype;

Figs. 12–14. Pachybrachis species, dorsal and lateral habitus, face, and pygidium. 12) P. trinotatus; lectotype;

Figs. 15–18. Pachybrachis species, dorsal and lateral habitus, face and pygidium. 15) P. bloxham, holotype;