Gracilaclopus Ocampo & Mondaca

Ocampo, Federico C. & Mondaca, José, 2012, Revision of the scarab subfamily Aclopinae Blanchard (Coleoptera: Scarabaeidae) in Argentina and Chile, Zootaxa 3409, pp. 1-29 : 6-7

Gracilaclopus Ocampo & Mondaca , new genus

( Figs. 5–32 )

Type species. Gracilaclopus electricus Ocampo & Mondaca , here designated

Diagnosis. This genus is distinguished from other aclopine genera by the following combination of characters: shape of the outer margin of the mandibles angulate (broadly rounded in Aclopus ; sinuate in Desertaclopus ); labral shape subrectangular and with apical margin strongly reflexed, (rounded and poorly or not reflexed in Aclopus and Desertaclopus ); frons and clypeus lacking transversal carinae (present in Desertaclopus ); mesotibiae and metatibiae with two transverse carinae (two in Aclopus ; one in Desertaclopus ); mesotibial spurs contiguous and metatibial spurs apart, metatarsus folds between spurs.

Description. Males. Scarabaeidae , Aclopinae , small to medium size (2.65–8.25 mm, width 1.35–3.65 mm), shape elongated with sub-parallel margins. Color: variable, light brown, brown, black, or bicolored. Head ( Figs. 5 , 8 , 10 , 12 , 15 , 17 , 19 , 21 ): Eye canthus well developed, anterior margin slightly reflexed, posterior margin bearing a few short setae (1–5); frontocanthal carina poorly developed or absent. Eyes well developed, clearly visible on dorsal view, rounded, barely divided by eye canthus. Frons generally flat on apical half, convex at base. Clypeus transverse; lateral margins oblique; anterior margin straight or slightly curved, slightly reflexed; frontoclypeal suture obsolete. Labrum protruding beyond clypeal margin, shape variable. Mandibles protruding beyond clypeal margin, angulate externally, concave dorsoventrally, lacking incisory teeth, molar area poorly developed, ventral surface moderately setose or glabrous. Labium longer than wide, strongly reduced, labial palps with three palpomeres, palpomere 3 as long as 1–2 combined; labial surface setose, setae dense to moderately dense, long and slender. Maxillae poorly developed, maxillary palp with 4 palpomeres. Antennae with 8 antennomeres; antennal club with 3 lamellae, surface glabrous. Pronotum ( Figs. 6 , 9 , 11 , 13, 14 , 16 , 18 , 20 , 22 .): Convex, wider than long; surface punctate, glabrous or with few setae. Marginal bead present in all margins (sometimes reduced on posterior margin in middle); anterior margin concave, with membrane well developed; lateral margins broadly rounded; posterior margin slightly sinuous. Anterior angle nearly right-angled, slightly acute or right-angled; posterior angles broadly rounded. Scutellum: Large , triangular, apex rounded or slightly acute. Elytra ( Fig. 14 ): Convex, longer than wide, lateral margins rounded. Surface punctate, punctures sparse to moderately dense, glabrous or setose, setae moderately long. Elytral striae absent, except for sutural striae; pseudoepipleura not developed. Vent er: Prosternal process with well developed columnar, densely setose. Metasternum long, ~0.7 times as long as wide; five ventrites exposed medially, ventrite 1 slightly visible; surface setose, setae long; ventrites 3 and 4 membranous on apical margin. Pygidium not exposed beyond clypeal margin, triangular, surface sparsely setose; setae long, slender. Legs ( Fig. 14 ): Femora robust, setose. Protibiae with two teeth, protibial spur not developed. Mesotibiae and metatibiae with two transverse carinae. Mesotibial and metatibial apex with fringe of thick setae. Mesotibial spurs contiguous, metatibial spurs apart. Metatibial tarsal insertion with notch, notch associated with tibial process. Tarsus longer than tibia, gracile. Protarsomeres, mesotarsomeres, and metatarsomeres 1 and 5 longer than 2, 3, 4 individually; all tarsi with long, apical setae. Protarsal claws curved or straight, simple, symmetrical ( Figs. 23–30 ). Male genitalia: Parameres symmetrical, slender; genital capsule not developed, genital segment represented by ventral plate; plate with apical margin slightly indented with few setae ( Fig. 27 c).

Remarks. The genus is distributed primarily in Argentina, although we studied one specimen of G. parvulus with label data for Bolivia. However, we are not convinced that the specimen was correctly labeled.

Etymology. The generic name comes from “gracil” from the Latin gracilis, meaning slender or thin in a charming or attractive way and “ Aclopus ” referring to the nominotypical genus of the subfamily.

Distribution. Argentina, Bolivia (unconfirmed data).

Figures

FIGURES 5 – 6. Gracilaclopus bidentulus, male.

FIGURE 7. Gracilaclopus bidentulus, female.

FIGURES 8 – 9. Gracilaclopus caceresi, male.

FIGURES 10 – 11. Gracilaclopus candelariae, male.

FIGURES 12 – 14. Gracilaclopus crepuscularis, male.

FIGURES 15 – 16. Gracilaclopus electricus, male.

FIGURES 17 – 18. Gracilaclopus morochus, male.

FIGURES 19 – 20. Gracilaclopus nigroscutatus, male.

FIGURES 21 – 22. Gracilaclopus parvulus, male.

FIGURES 23 – 30. 23) Male genitalia of G. bidentulus, aedeagus lateral view; 24) G. c a c e re s i, aedeagus lateral view; 25) G. candelariae, aedeagus lateral view; 26 a – b) G. crepuscularis, aedeagus lateral and frontal views respectively; 27 a – c) G. electricus, a – b) aedeagus lateral and frontal views, c) ventral plate of the genital segment; 28) G. m o ro c h u s, aedeagus lateral view; 29) G. nigroscutatus, aedeagus lateral view; 30) G. parvulus, aedeagus lateral view.

FIGURE 31. Distribution map of Gracilaclopus bidentulus, G. caceresi, G. c a n d e l a r i a e, and G. crepuscularis.

FIGURE 32. Distribution map of Gracilaclopus electricus, G. m o ro c h u s, G. nigroscutatus, and G. parvulus.