Ctenotis Burmeister, 1855

Katovich, Kerry, 2008, A generic-level phylogenetic review of the Macrodactylini (Coleoptera: Scarabaeidae: Melolonthinae), Insecta Mundi 2008 (23), pp. 1-78 : 36-38

Ctenotis Burmeister, 1855

( Figure 72-76 )

Ctenotis Burmeister, 1855: 20 . Type species Ctenotis obesa Burmeister, 1855 , by monotypy.

Taxonomic Notes

The following generic diagnosis is based on a dissected syntype of the generic type species, C. obesa (MLUH) .

Generic diagnosis

This genus is characterized by its large size, and rotund body; prementum quadrate, anteromedial region bulbous; elongate labrum and semicircular clypeus, antennae with 10 antennomeres, with

antennomeres 6-10 forming an elongate club; pronotum with anterior margin less in width than posterior margin.

Generic redescription

Measurements: Prothorax at widest point 6.5 mm, elytra at widest point of elytra 9.0 mm, length 18.0 mm.

Color and vestiture: Body dark brown, pronotum and elytra covered with a vestiture consisting of small fine grey setae, ventrites of thorax with long golden setae, abdomen with small grey setae and patches of long golden setae.

Head: Clypeus not coplanar with frons; frons angled at 30 o; labrum in frontal view, broadly oval, deeply emarginate, labrum not coplanar with clypeus; labium with prementum quadrate, anteromedial region of mentum bulbous, posterior region flat ( Fig. 74 ); mandibles in dorsal view semicircular, scissorial area bluntly produced adorally, thin in lateral profile, bilobed, molar area bluntly produced, well sclerotized; maxillary palpi with apical palpus broadly ovate, flattening distally in lateral profile, 2X length of 3 rd segment, apex with a circular sensory region; antennae 10-segmented ( Fig. 75 ), segments 6-10 broadly ovate, forming the elongate club, 6 th segment smaller, 1/4 length of 7 th segment, segments 7-10 equal to length of segments 1-6 combined.

Prothorax: Pronotum oblong ( Fig. 76 ), transverse, widest medially, anterior angle obtuse, lateral margins gradually narrowing anteriorly, straight posteriorly, posterior angle acute, posterior margin straight, medially lobed; prothoracic leg with coxa transverse; tibia bidentate, thin spur present at distal 3/4; pretarsus with claws widely divergent, equal in length, both claws narrowly split, outer lobe narrow, lower lobe broad on individual claw.

Mesothorax: Scutellum subtriangular; elytra wider than long, widest in posterior 3/4, elytral epipleuron flattened, margin lacking membrane, dorsal surface lacking striae, densely covered with fine setiferous punctures, anterior umbone prominent, posterior umbones weakly developed; pretarsus similar to prothoracic pretarsus.

Metathorax: Metathoracic leg with coxa narrowly separated; femur ovate, widest distally, gradually widening toward distal margin; tibia rectangular, width uniform, posteroventral margin with pair of large spurs, spurs of equal length, arising from same level as tarsal articulation joint, posterior margin with a deep, U-shaped tarsal articulation groove; pretarsus with claws similar to prothoracic legs.

Abdomen: Ventrites 2-4 subequal in length, 5 th ventrite (= propygidium) slightly larger than 4 th ventrite length, ventrite and sternite of 5 th abdominal segment not separated by a suture, spiracle placed medially, 6 th ventrite equal to length of 4 th ventrite, posterior margin membranous; pygidium broadly triangular, wider than long, posterior margin rounded.

Diversity and Geographic Distribution

Ctenotis is monotypic, with C. obesa known only from Brazil.

Figures

Figure 72-76. Ctenotis obesa Burmeister. 72) Dorsal habitus. 73) Left lateral view. 74) Prementum, ligula and labial palpi, ventral view. 75) Antenna. 76) Pronotum, dorsal view.