Gama Blanchard, 1850

Katovich, Kerry, 2008, A generic-level phylogenetic review of the Macrodactylini (Coleoptera: Scarabaeidae: Melolonthinae), Insecta Mundi 2008 (23), pp. 1-78 : 41-42

Gama Blanchard, 1850

( Figure 88-93 )

Gama Blanchard, 1850 ; 118. Type species Gama grandicornis Blanchard, 1850 , by subsequent designation ( Lacordaire 1856: 265). Harpodactyla Burmeister, 1855: 118 . Type species Harpodactyla grandicornis Burmeister, 1855 , by subsequent designation ( Evans 2003: 268). Synonym proposed by Dalla Torre (1913).

Taxonomic Notes

The following generic characterized is based on two syntypes of Gama viridifusca Moser , located at ZMHB. The type of G. grandicornis Blanchard was not located at the MNHC. Additional Gama species described by Blanchard were located at the MNHC. The generic limits were compared with the syntypes of G. viridifusca . Additionally, a syntype of the generic type species G. grandicornis (Burmeister) (MLUH) was examined.

Generic diagnosis

This genus is recognized by its elongate body; prementum quadrate, ventral surface often medially grooved; pronotum oblong, with posterior margin medially with a pair of short, acute, teeth; mesothoracic leg of males with an elaborate metatarsus, often hook-like.

Generic redescription

Measurements: Prothorax at widest point 4.0 mm, elytra at widest point 4.2 mm, length 10.5 mm.

Color and vestiture: Body mottled brown and green, surface shiny and reflective, vestiture lacking.

Head: Clypeus not coplanar with frons; frons angled at 45 o; labrum in frontal view ovate, medially with a deep emargination, labrum coplanar with clypeus; labium with prementum quadrate, ventral surface raised slightly, rounded, (medially grooved in G. grandicornis ) ( Fig. 90 ); mandibles in dorsal view rectangular, scissorial region directed aborally, medially lobed, molar area well sclerotized, prominent; maxillary palpi with apical segment elongate, ovate; antennae with 9 antennomeres, antennomeres 7-9 forming the elongate club, equal to antennomeres 2-6 combined.

Prothorax: Pronotum oblong, transverse, widest medially, anterior angle obtuse, lateral margin convex, posterior angle acute, posterior margin straight, weakly bidentate ( Fig. 91 ); prothoracic leg with coxa transverse; tibia weakly dentate; pretarsus with claws widely divergent, equal in length, both claws broadly split, upper lobe narrow, lower lobe broad on individual claw.

Mesothorax: Mesothoracic leg with metatarsus oblong, transverse, broadly arrow shaped, angled dorsally, dorsal margin straight, rounded on dorsoventral margin, anterior ventral margin produced in a flange, posterior ventral margin with a narrow hook, posterior surface scooped out, width equal to 2 nd tarsomere width ( Fig. 92 ); scutellum subtriangular; elytra longer than wide, width uniform, dorsal surface with weak striae, patches of broad white setae, anterior umbone slightly produced, posterior umbone prominent; pretarsus similar to prothoracic pretarsus.

Metathorax: Metathoracic leg with coxae widely separated; femur narrowly ovate, widest medially; tibia vase-shaped, narrow proximally, widest in proximal 1/4, narrowing in distal 1/4, distoventral margin with pair of equal, long, flattened spurs, spurs arise at same level as tarsal articulation joint, posterior margin with a deep, U-shaped groove; pretarsus with claws similar to prothoracic and mesothoracic claws.

Abdomen: Ventrites 2-4 equal in length, sutures distinct, length of 5 th ventrite equal to length of 3 rd and 4 th ventrites combined, posterior margin concave, ventrite and sternite of 5 th abdominal segment lacking a suture, spiracle situated in posterior 1/4, 6 th ventrite ovate in ventral profile; pygidium subtriangular, wider than long, posterior margin rounded ( Fig. 93 ).

Diversity and Geographic Distribution

Gama comprises 29 species, primarily from Brazil, with a limited number of species from Argentina,

Colombia, and Venezuela. No key to species currently exists.

Figures

Figure 88-93. Gama viridifusca Moser (male syntype). 88) Dorsal habitus. 89) Left lateral view. 90) Prementum, ligula and labial palpi, ventral view. 91) Pronotum, dorsal view. 92) Mesothoracic tibia and tarsi. 93) Pygidium, ventral view.