Issacaris Fairmaire, 1889

Katovich, Kerry, 2008, A generic-level phylogenetic review of the Macrodactylini (Coleoptera: Scarabaeidae: Melolonthinae), Insecta Mundi 2008 (23), pp. 1-78 : 49

Issacaris Fairmaire, 1889

( Figure 115-119 )

Issacaris Fairmaire, 1889: 117 . Type species Issacaris petalophora Fairmaire, 1889 , by monotypy.

Taxonomic Notes

The following generic diagnosis is based on a single dissected male homeotype of the presumptive syntype of the type species I. petalophora located at the MNHC and identified with a Fairmaire label .

Generic diagnosis

This genus is characterized by its large size, rectangular shape of elytra; large, globose eyes; pronotum oblong, transverse, widest medially; prementum elongate weakly subtriangular, medially grooved; clypeus semicircular in dorsal view, labrum narrowly ovate in frontal view; pygidium subtriangular, wider than long.

Generic redescription

Measurements: Prothorax at widest point 7.0 mm, elytra at widest point 10.0 mm, length 17.0 mm.

Color and vestiture: Head black, pronotum dark reddish brown, elytra light brown, abdomen and thorax reddish brown, ventral surface with vestiture consisting of long, golden setae.

Head: Clypeus not coplanar with frons; frons angled at 10 o; labrum in frontal view narrowly ovate, weakly emarginate, labrum not coplanar with clypeus; labium with prementum elongate, weakly subtriangular, ventral surface medially grooved ( Fig. 117 ); mandibles in dorsal view subtriangular, scissorial area reduced to a rounded apex, not prominently produced adorally, molar area not produced adorally, weakly sclerotized; maxillary palpi with apical palpus ovate, equal to length of segments 2-3, apex acute; antennae with 8 antennomeres, antennomeres 6-8 forming the very elongate club, club length equal to length of antennomeres 1-5 combined ( Fig. 118 ).

Prothorax: Pronotum oblong, transverse, widest medially, anterior angle obtuse, lateral margins convex, margins with a narrow bead, posterior angle obtuse, posterior margin straight, medially lobed, dorsal surface weakly lobed ( Fig. 119 ); prothoracic leg with coxa transverse; tibia dentate, distal 1/3 with a long spur; pretarsus with claws not divergent, equal in length, both claws narrowly split, outer lobe narrow, slightly longer than lower lobe, lower lobe broad on individual claw, base of claw toothed.

Mesothorax: Scutellum subtriangular; elytra wider than long, widest in posterior 3/4, elytral epipleuron flattened, grooved, dorsal surface with several weak, punctate striae, strial intervals slightly raised anterior umbone strong, posterior umbone weak; pretarsus similar to prothoracic pretarsus.

Metathorax: Metathoracic leg with coxa widely separated; femur broadly ovate, widest medially; tibia rectangular, proximally narrow, width uniform, posteroventral margin lacking spurs, posterior margin with a broad, shallow U-shaped groove; pretarsus similar to pro- and mesothoracic legs.

Abdomen: Ventrites 2-4 equal in length, 5 th ventrite (= propygidium) equal to length of ventrites 2-3 combined, posterior margin membranous, ventrite and sternite of 5 th abdominal segment with a partial suture, spiracle placed medially, at apex of suture, length of 6 th ventrite equal to 1/2 length of 5 th ventrite; pygidium subtriangular, wider than long, posterior margin rounded.

Diversity and Geographic Distribution Issacaris comprises three species, all known only from Chile. A key is provided by Gutiérrez (1952).

Figures

Figure 115-119. Issacaris petalophora Fairmaire (male). 115) Dorsal habitus. 116) Left lateral view. 117) Prementum, ligula and labial palpi, ventral view. 118) Antenna. 119) Pronotum, scutellum and elytra, dorsal view.