Dasyus 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 : 38-39

Dasyus Le Peletier and Serville, 1828

( Figure 77-81 )

Dasyus Le Peletier and Serville, 1828: 369 . Type species Dasyus collaris Le Peletier and Serville, 1828 , by monotypy.

Taxonomic Notes

The following generic diagnosis is based on two dissected male homeotypes of the presumptive syntype of the type species D. collaris located at the MNHC and identified with a Le Peletier label .

Generic diagnosis

This genus is characterized by its ovate body; prementum elongate, ventral surface medially grooved; pretarsus of meso and metathoracic legs with claws equal, divergent, simple; ventromedial surface of 6 th ventrite with a semicircular shaped pocket, margins of which are raised, posterior margin sinuate; pygidium subtriangular, width equal to length, posterior margin blunt.

Generic redescription

Measurements: Prothorax at widest point 3.0 mm, elytra at widest point 3.6 mm, length 8.0 mm.

Color and vestiture: Head and abdomen black, thorax red, vestiture consisting of short, yellow setae, femora reddish-brown, tibiae and tarsomeres black.

Head: Clypeus coplanar with frons, frons angled at 30 o; labrum in frontal view narrowly ovate, weakly emarginate, slightly produced anteriorly from clypeus, labrum not coplanar with clypeus; labium with prementum elongate, ventral surface with medial groove ( Fig. 79 ); mandibles in dorsal view subtriangular, scissorial area bluntly produced, angled adorally, weakly concave, medially with a small acuminate point, molar area well developed; maxillary palpi with apical palpus ovate, elongate, equal to 3X length of 2 nd segment, distally with a small sensory spot; antennae with 9 antennomeres, antennomeres 7-9 forming the elongate club, equal to length of antennomeres 2-6 combined.

Prothorax: Pronotum oblong, transverse, widest medially, anterior angle obtuse, lateral margin convex, posterior angle obtuse, posterior margin convex, medially lobed ( Fig. 80 ), in dorsal view strongly rounded; prothoracic leg with coxae elongate; tibia lacking teeth, medially with a stout spur; pretarsus with claws strongly divergent, equal in length, both claws narrowly split, outer lobe narrow, inner lobe broad on individual claw.

Mesothorax: Scutellum subtriangular; elytra ovate, width equal to length, elytral epipleuron forming a rounded bead, margin with a slight membranous border, dorsal surface with raised striae absent, surface punctate, punctures in distinct vertical lines, anterodorsal region weakly raised, anterior umbone prominent, posterior umbone moderately produced; pretarsus of mesothoracic leg with claws equal, divergent, simple.

Metathorax: Metathoracic leg with coxae clearly separated; femur broadly ovate, widest medially; tibia subtriangular, widest medially, narrow proximally, posteroventral margin with a pair of long, stout spurs, anterior spur slightly above posterior spur, spurs arise above tarsal articulation joint, posterior margin with a deep U-shaped groove; pretarsus with claws similar to mesothoracic legs.

Abdomen: Ventrites 2-4 subequal in length, 5 th visible ventrite (= propygidium) equal in length to ventrites 2-4 combined, ventrite and sternite of 5 th abdominal segment lacking a complete suture, slight depression present posterad of spiracle, spiracle placed medially, sixth ventrite equal to length of 5 th and 4 th ventrite combined, ventromedial surface with a semicircular shaped pocket, margins of which are raised, posterior margin sinuate ( Fig. 81 ); pygidium subtriangular, width equal to length, posterior margin blunt.

Diversity and Geographic distribution

Dasyus contains two species, both known only from Brazil.

Figures

Figure 77-81. Dasyus collaris Le Peletier and Serville. 77) Dorsal habitus. 78) Left lateral view. 79) Prementum, ligula and labial palpi, ventral view. 80) Pronotum, dorsal view. 81) Visible abdominal segments, ventral view.