Chariodactylus Moser, 1919

Katovich, Kerry, 2008, A generic-level phylogenetic review of the Macrodactylini (Coleoptera: Scarabaeidae: Melolonthinae), Insecta Mundi 2008 (23), pp. 1-78 : 30-32

Chariodactylus Moser, 1919

( Figure 54-57 )

Chariodactylus Moser, 1919a: 45 . Type species Chariodactylus chacoensis Moser, 1919a , by subsequent designation ( Evans 2003: 247).

Taxonomic Notes

The following generic diagnosis is based on a dissected paratype of the type species, C. chacoensis (ZMHB) .

Generic diagnosis

This genus closely resembles Macrodactylus , but is characterized by the hexagonal pronotum, elongate, subtriangular scutellum; and the elongate metatarsus of the metathoracic legs.

Generic redescription

Measurements: Prothorax at widest point of prothorax 3.0 mm, elytra at widest point 4.2 mm, length 11.0 mm.

Color and vestiture: Body reddish-brown, surface covered with a vestiture consisting of short and long white setae.

Head: Clypeus coplanar with frons, angled at 30 o; labrum in frontal view oval, narrow, weakly emarginate, labrum coplanar with clypeus; labium with prementum rectangular, elongate (2X longer than wide), ventral surface with medial groove ( Fig. 56 ); mandibles in dorsal view triangular, narrowest anteriorly, scissorial area reduced to a membrane, lined with dense setae, molar area well developed, bluntly produced adorally; maxillary palpi with apical palpus ovate, equal to length of 3 rd segment, apex obtuse, distally with a sensory region; antennae with 9 antennomeres, antennomeres 7-9 forming the elongate club, lamellae thin, equal to length of antennomeres 3-6 combined.

Prothorax: Pronotum hexagonal, oblong, transverse, widest medially, anterior angles obtuse, lateral margin convex, posterior angles obtuse, posterior margin convex ( Fig. 57 ), in dorsal view rounded; prothoracic leg with coxa elongate; tibia weakly dentate; pretarsus with claws divergent, equal in length, both claws narrowly split, upper lobe narrow, lower lobe broad on individual claw, base of claw toothed.

Mesothorax: Scutellum subtriangular; elytra longer than wide, widest at anterior margin, elytral epipleuron flattened, margin lined with a thin membrane, dorsal surface with distinct striae, intervals punctate, slightly convex, surface covered with short and long setae, anterior umbone strongly developed, posterior umbone weakly developed; pretarsus similar to prothoracic pretarsus.

Metathorax: Coxa widely separated; femur narrowly ovate, width uniform; tibia narrowly subtriangular, broader distally, posteroventral margin lacking spurs, posterior margin lacking tarsal articulation groove; pretarsus with claws similar to prothoracic legs.

Abdomen: Ventrites 2-4 subequal in length, 5 th visible ventrite (= propygidium) equal to length of 4 th and 1/2 length of 3 rd ventrite combined, ventromedial surface transitioning to membranous posterior margin, ventrite and sternite of 5 th abdominal segment lacking a complete suture, spiracle placed medially; 6 th ventrite equal in length to 5 th ventrite, ventromedially transitioning to membranous posterior margin, in lateral view broadly triangular; pygidium subtriangular, longer than wide, posterior margin rounded.

Diversity and Geographic Distribution

Chariodactylus comprises two species recorded from Bolivia and Peru.

Figures

Figure 54-57. Chariodactylus chacoensis Moser (male). 54) Dorsal habitus. 55) Left lateral view. 56) Prementum, ligula and labial palpi, ventral view. 57) Pronotum, dorsal view.