Chremastodus Solier, 1851

Katovich, Kerry, 2008, A generic-level phylogenetic review of the Macrodactylini (Coleoptera: Scarabaeidae: Melolonthinae), Insecta Mundi 2008 (23), pp. 1-78 : 33-35

Chremastodus Solier, 1851

( Figure 63-66 )

Chremastodus Solier, 1851: 103 . Type species Chremastodus pubescens Solier, 1851 , by subsequent designation ( Evans 2003: 248).

Cremastodus Solier, 1851 , Dalla Torre, 1913 [spelling error]

Taxonomic Notes

The following generic diagnosis is based on a dissected specimen of C. marmoratus (Curtis) located at the BMNH and identified with a Curtis determination label. The type of C. marmoratus was not located at the BMNH. The type species C. pubescens Solier was located at the MNHC, but it was not dissected because it was a single specimen. The generic limits of the genus were compared to C. marmoratus .

Generic diagnosis

This genus resembles Macrodactylus , but is characterized by the uneven, mottled elytral surface, oblong pronotum, and prominent umbones.

Generic redescription

Measurements: Prothorax at widest point 3.0 mm, elytra at widest point of elytra 4.0 mm, length 7.5

mm.

Color and vestiture: Body dark brown to mottled black, vestiture consisting of long, scale-like white setae.

Head: Clypeus coplanar with frons, frons angled at 45 o; labrum in frontal view, narrowly ovate, weakly emarginate; labium with prementum rectangular, elongate, medially grooved ( Fig. 65 ); mandibles in dorsal view rectangular, scissorial area reduced to a membrane, lined with dense setae, molar area reduced; maxillary palpi with apical segment ovate, equal to segments 2-3, apex obtuse, with blunt sensory region; antennae with antennomeres, antennomeres 7-9 forming the elongate club, lamellae thin, equal in length to antennomeres 2-5 combined.

Prothorax: Pronotum oblong, transverse, wider than long, widest medially, anterior angles acute, lateral margin convex, posterior angles obtuse, posterior margin weakly convex, medially obtuse ( Fig. 66 ); coxa transverse, tibia dentate; pretarsus with claws divergent, equal in length, both claws narrowly split, outer lobe narrow, slightly longer then lower lobe, lower lobe narrow on individual claw.

Mesothorax: Scutellum subtriangular; elytra longer than wide, width uniform, elytral epipleuron flattened, margin setose, dorsal surface with three weakly raised striae, anterior and posterior umbones strongly developed; pretarsus similar to prothoracic pretarsus.

Metathorax: Metathoracic leg with coxa contiguous; femur broadly ovate, widest medially; tibia subtriangular, narrow proximally, widest distally, posteroventral margin lacking spurs, posterior margin with a deep U-shaped groove; pretarsus with claws similar to prothoracic legs.

Abdomen: Ventrites 2-4 subequal in length, 5 th visible ventrite (= propygidium) equal in length to ventrites 3-4 combined, posterior margin membrane like, ventrite and sternite of 5 th abdominal segment

with suture lacking, spiracle placed medially, 6 th ventrite equal to length of 3/4 5 th ventrite length, triangular in lateral profile; pygidium subtriangular, width equal to length, posterior margin rounded. Diversity and Geographic distribution

Chremastodus contains two species, both of which are recorded only from Chile.

Figures

Figure 63-66. Chremastodus marmoratus (Curtis). 63) Dorsal habitus. 64) Left lateral view. 65) Prementum, ligula and labial palpi, ventral view. 66) Head and pronotum, dorsal view.