Plectris Le Peletier and Serville, 1828

Katovich, Kerry, 2008, A generic-level phylogenetic review of the Macrodactylini (Coleoptera: Scarabaeidae: Melolonthinae), Insecta Mundi 2008 (23), pp. 1-78 : 57-59

Plectris Le Peletier and Serville, 1828

( Figure 146-150 )

Plectris Le Peletier and Serville, 1828: 369 . Type species Plectris tomentosa Le Peletier and Serville, 1828 , by monotypy.

Euryaspis Blanchard, 1851: 130 . Type species Euryaspis gaudichaudii Blanchard, 1851 , by monotypy.

Synonymized by Dalla Torre (1913).

Junkia Dalla Torre, 1913: 310 . (for Trichoderma Nonfried ) Type species Trichoderma ceylanica Nonfried,

1894, by monotypy.

Trichoderma Nonfried, 1894: 11 . (preoccupied name), Type species Trichoderma ceylanica Nonfried,

1894, by monotypy.

Pseudoserica Guérin-Méneville, 1830: 86 . Type species Pseudoserica marmorea Guérin-Méneville,

1830, by monotypy. Synonymized by Dalla Torre (1913).

Taxonomic Notes

The following generic diagnosis is based on a dissected homeotype of P. micans (Bates) , type located at the BMNH. The generic limits of this genus were compared to a dissected homeotype of the presumptive syntype of the generic type species, P. tomentosa Le Peletier and Serville located at the MNHC and identified with a Le Peletier label. Plectris micans was used for the generic diagnosis based on the poor photo quality of P. tomentosa and its rarity.

Generic diagnosis

This genus is characterized by its elongate body; prementum rectangular, ventral surface flattened, occasionally lobed or weakly grooved; prominent ligula, appearing bilobed, a shallow groove present medially; pretarsus of meso and metathoracic legs with claws often unequal.

Generic redescription

Measurements: Prothorax at widest point 6.0 mm, elytra at widest point 8.0 mm, length 15.0 mm.

Color and vestiture: Body reddish brown, metallic, vestiture consisting of fine, white setae, sutural striae with tufts of white setae.

Head: Clypeus not coplanar with frons; frons angled at 30 o; labrum in frontal view ovate, large, with a deep medial groove ( Fig. 148 ), labrum not coplanar with clypeus; labium with prementum rectangular, ventral surface medially grooved, prominent ligula, appearing bilobed, ( Fig. 149 and 150 ); mandibles in dorsal view rectangular, scissorial area bluntly produced into broadly rounded process, posteriorly with a raised process, molar area prominent, mandible in lateral profile triangular; maxillary palpi with apical palpus ovate, elongate, apex obtuse; antennae with 10 antennomeres, antennomeres 7-10 forming the elongate club, equal to length of antennomere one.

Prothorax: Pronotum oblong, transverse, widest medially, anterior angle acute, lateral margins convex, serrate, posterior angle obtuse, posterior margin concave, medially lobed; prothoracic leg with coxa transverse; tibia dentate, ventral margin with a small, broad spur; pretarsus with claws weakly divergent, equal in length, both claws broadly split, upper lobe narrow, lower lobe broad.

Mesothorax: Scutellum subtriangular; elytra longer than wide, widest medially, in lateral profile epipleuron forming a narrow flattened margin, elytral surface with three weak vertical striae, striae smooth, with scattered long white setae, inter strial regions rugose, setose, anterior umbone moderate, posterior umbone weak; pretarsus with claws equal, weakly divergent, both claws broadly split, upper lobe narrow, lower lobe broad.

Metathorax: Metathoracic leg with coxae narrowly separated; femur narrowly ovate, widest medially; tibia vase-shaped, narrow proximally, widest medially, posteroventral margin with a pair of stout spurs, arising at same level as tarsal articulation joint, posterior margin with a distinct U-shaped groove; pretarsus with claws equal, weakly divergent, both claws broadly split, upper lobe narrow, lower lobe broad.

Abdomen: Ventrites 2-4 subequal in length, 5 th ventrite (= propygidium) equal to length of ventrites 3- 4 combined, ventrite and sternite of 5 th abdominal segment with a groove appearing as a partial suture, spiracle located medially, at apex of groove, 6 th ventrite length equal to length of 4 th ventrite; pygidium subtriangular, wider than long, posterior margin rounded.

Diversity and Geographic Distribution

Plectris comprises 353 species, distributed in Argentina, Australia (exotic), Brazil, Bolivia, Colombia, Ecuador, French Guiana, Guatemala, Guyana, Martinique, Mexico, Nicaragua, Panama, Paraguay, Peru, Saint Vincent, United States (exotic), Uruguay, and Venezuela. Regional keys are provided by Frey (1967) and Chalumeau (1982).

Figures

Figure 146-150. Plectris micans (Bates). 146) Dorsal habitus. 147) Left lateral view. 148) Clypeus and labrum, frontal view. 149) Prementum, ligula and labial palpi, ventral view. 150) Plectris tomentosa Le Peletier and Serville prementum, ligula and labial palpi, ventral view.