Gromphas Brullé 1837

Figueroa, Luis, Edmonds, W. D. & Meza-Velez, Felipe, 2012, The genus Gromphas Brullé, 1837 in Peru (Coleoptera: Scarabaeidae: Scarabaeinae: Phanaeini), Insecta Mundi 2012 (248), pp. 1-8 : 2-3

Genus Gromphas Brullé 1837 (not 1834)

Gromphas Brullé, 1837: 304 (as a “subgenus” of Copris ). Type species: not designated (see below)

Brullé’s description of Gromphas states “Ce sous-genre se compose d’une seule espèce ...”, but he neglects to mention its name. His only basis is a vague reference to Dej[ean] (presumably Dejean, 1836 - 1837), who cites “Lacordairei Dej.” as the only included species of “ GROMPHAS Dejean. ” But “ Gromphas lacordairei ”, also attributed to Brullé, is nowhere described as far as we know. Resolution of these nomenclatural puzzles is far beyond the scope of this paper and is currently under consideration by Mario Cupello (pers. comm.). For present purposes we use the names Gromphas and G. lacordairei as currently understood in common usage. Heretofore the date of publication of Brullé’s description of Gromphas has been cited as 1834. We here correct the date to 1837, the date of publication of his third volume on Coleoptera in the Histoire Naturelle des Insectes series in which Gromphas is formally established (see Musgrave 1932: 8). The following description of the genus does not thoroughly consider G. dichroa Blanchard , which we know only from photographs and published descriptions as well as observations graciously supplied by Mario Cupello.

Generic Description. General - Medium size, overall length usually no more than 20 mm. Dorsum usually shining and with some metallic reflections ( Fig. 1-4); sexual dimorphism subtle, expressed mainly by characters of prolegs. Head - Clypeal margin (seen from above, Fig. 6, 12) broadly bidentate medially, teeth rounded; junction of clypeal and genal margins strongly notched ( Fig. 6, arrow). Clypeal process a transverse, marginally curved ridge ( Fig. 15). Frontoclypeal carina (seen from above) strongly bowed anteriorly, usually interrupted medially by an emarginate tubercle or conical horn ( Fig. 6, 12). Antennal club ( Fig. 10) rounded, three lamellae exposed (basal lamella not hollowed apically to receive apical segments). Prothorax - Pronotum usually evenly convex and lacking prominent surface features (except G. aeruginosa ). Pronotum densely, finely granulate ( Fig. 11), granulation becoming weaker, sometimes obsolete posteromedially. Posterior pronotal margin distinctly, finely carinate or carina largely obliterated. Posterior pronotal fossae shallow, sometimes indistinct ( Fig. 2-3, 9). Pterothorax - Intercoxal portion of metasternum angulate anteromedially; apex (seen from side) rounded, with flattened, declivitous sides ( Fig. 13). Dorsal margin of metepisternum curved downward posteriorly, not produced as rounded tab that engages edge of elytron ( Fig. 14). Legs - Male lacking protarsi ( Fig. 16, 17); female with foursegmented protarsi ( Fig. 18, 19). Meso- and metatarsi five-segmented, clawless. Inner apical protibial angle of male with conspicuous pencil of long setae ( Fig. 17, arrow) sometimes accompanied by an inwardly directed, acute spine ( Fig. 20, arrow); females often possessing setal pencil above insertion of tarsus. Protibial spurs acute, gently bent medially ( Fig. 17, 20-21), sometimes angulate along outer margin. Protibiae quadridentate in both sexes ( Fig. 16-17); all but basal tooth carinate on outer (dorsal) surface ( Fig. 16). Elytra - Combined width at humeral angles clearly greater than length along suture ( Fig. 2-3). Anterior ends of striae not fossate ( Fig. 9). Striae fine, superficial, sometimes carinulate, puncturing usually obsolete; eighth stria effaced anteriorly. Interstriae flat or weakly convex. Pygidium - Basal piece (propygidium) not separated from pygidium by transverse carina ( Fig. 7; except G. dichroa ). Aedeagus - Ventral margin of phallobase narrowly grooved medially ( Fig. 23, arrow), groove embracing fissure (most easily viewed submerged in alcohol, Fig. 22). Coprophagous species.

Generic Diagnosis. Species of Gromphas can be distinguished from other Peruvian dung beetles by the following combination of characters: Prominent notch separating clypeal and genal margins ( Fig. 6, arrow); evenly convex and shining pronotum (except G. aeruginosa ); the bluntly acuminate metasternum ( Fig. 13); four-segmented protarsi in female ( Fig. 18-19, protarsi absent in male); propygidium and pygidium not separated by transverse carina ( Fig. 7). They will key to couplet 54 in Vaz-de-Mello et al. (2011).

Geographical distribution. South America east of the Andes.

Included Species. Four species are currently assigned to Gromphas : G. lacordairei Brullé , G. amazonica Bates , G. dichroa Blanchard , and G. aeruginosa (Perty) . Only G. aeruginosa and G. amazonica are known from Peru.

Species Diagnoses. The Peruvian species are very distinct from each other and can be distinguished easily as follows: