Genieridium, Vaz-De-Mello, 2008

Vaz-De-Mello, Fernando Z., 2008, Synopsis of the new subtribe Scatimina (Coleoptera: Scarabaeidae: Scarabaeinae: Ateuchini), with descriptions of twelve new genera and review of Genieridium, new genus, Zootaxa 1955, pp. 1-75 : 26-27

6. Genieridium new genus

Diagnosis: Moderate to large-sized species (only rare specimens of G. cryptops measure less than 3.7 mm), oval-elongate shape ( Figs. 21–22); clypeal teeth two (Figs. 55, 60, 62, 64, 70) or none, in the latter case clypeus widely emarginated (Figs. 57, 68). Eyes, in dorsal view, absent or very small, distanced by more than 12 times eye width. Pronotum separated from hypomeron by weak carina (Fig. 59). Elytra convex at least in the anterior half. Length of mesotibiae and metatibiae at least three times apical width. Males with mesal apical protibial teeth; all claws bent (mesoclaws and metaclaws less modified than proclaws); and last tarsomere of prolegs modified to receive claws. Length of last abdominal sternite along midline equal to or less than medial width of metafemur; pygidium, in ventral view, occupying more than two-fifths of abdominal horizontal length.

Description: Length 3.5–6.5 mm, body oval elongated, convex ( Figs. 21–22), color grey to black, brown in teneral specimens, shiny or opaque, lacking any traces of metallic sheen. Clypeus with two teeth or none, always with central anterior concavity coincident with emargination, which is also present in toothless species (Figs. 57, 68). Clypeus laterally regularly rounded, continuous with genal border. Clypeofrontal and clypeogenal sutures indistinct, head lacking any traces of carinae or tubercles. Eyes, in dorsal view, absent or very small, when present elongated, more than three times their width; interocular width at least 12 times eye width (Figs. 55, 57, 60, 62, 64, 68, 70). Pronotum lacking anterior or posterior beads, simply convex, with lateral callosities distinguished only by lack of punctation; disc covered by simple setose punctures and separated of hypomeron by weak but distinct carina interrupted by regular setose punctures. Hypomeron ventrally with strong lateral longitudinal carina; mesoepimera with transverse anterior carina stronger mesally. Metasternum with simple setose punctures on disc. Elytra with one or two rows of setose punctures, discal interstriae flat all along; striae apically deeper and slightly wider than on disc. Pseudoepipleura gradually narrowed posteriorly, superiorly with complete row of setose punctures. Protibiae with three strong teeth distributed along at least apical three-fifths, basally denticulate, with ventral scale-like setae. Mesotibiae and metatibiae strongly widened apically, apical width more than third of tibial length. Parameres flattened, right-angled in relation to phallobase, shorter than half of phallobase length. Spermatheca simply C-shaped, in one case ( G. cryptops ) with elongated base and apex. Coxites triangular and symmetrical.

Sexual dimorphism: Males have proclaws bent at midlength, and mesoclaws and metaclaws also modified, either bent at midlength or larger than in females and with stronger basal angle; protarsus with last tarsomere modified to receive claws; metasternal disc strongly concave (less concave or flat in females), pygidium narrower than in females, and each tibia with apicomesal tooth, sometimes modified in laminate anteriorly directed apodeme in metatibia.

Type species: Pedaridium bidens Balthasar, 1942 (present designation) = Genieridium bidens ( Balthasar, 1942) , new combination.

Etymology: After François Génier, good friend and scarabeidologist, companion in so many works and ideas. Gender neutral.

Distribution: Colombia, Venezuela, non-Amazonian Brazil, eastern Bolivia, Paraguay, and northeastern Argentina. The genus shows a disjunct distribution, with one group in the Caribbean subregion (Northwestern South American dominion), occupying the Cauca, Maracaibo, Venezuelan Coast and Venezuelan Llanos provinces, and the other in the Chacoan, Parana and Amazonian subregions, occupying the Pantanal, Caatinga, Cerrado, Chaco, Brazilian Atlantic Forest, Parana Forest, and Araucaria angustifolia Forest provinces ( Figs. 104–107).

Remarks: The position of Genieridium was not resolved, and it was recovered in a trichotomy with Pedaridium and Nunoidium . The new genus main external synapomorphies are the elongation and inclined orientation of pygidium, and the punctation interrupting the pronotal-hypomeral carina. Apart from characters mentioned as synapomorphies of Genieridium , it can be distinguished from Pedaridium by the much shorter phallobase, differently shaped internal sac sclerites ( Pedaridium lacks all but the pseudoflagellum), lack of basal “tooth” in the spermatheca, elytra conjointly convex ( Pedaridium has clearly tectiform elytra, separately flattened), lack of longer setae on the anterior part of pronotum and lack of a pronotal lateral expansion. From Nunoidium it is readily distinguished by the lack of a posterior pronotal bead, reduction of lateral bead, reduced eyes, and presence of sexually dimorphic claws. This genus includes two clearly delimited monophyletic, biogeographically-defined groups: species from Venezuela and Colombia are characterized by strong modification of male metalegs (with flattened, blade-like apicomesal tooth) and southern species by the reduction of the seventh elytral stria.

Composition: Besides the type species, the genus is presently defined to include G. cryptops ( Arrow, 1913) , new combination; G. paranense ( Arrow, 1932) , new combination; G. bordoni ( Martínez, 1992) , new combination; G. zanunciorum ( Vaz-de-Mello & Canhedo, 1998), new combination; G. margareteae ( Génier & Vaz-de-Mello, 2002), new combination; and G. medinae ( Gill & Vaz-de-Mello, 2003), new combination (all described as Pedaridium ). Because no undescribed species of this genus are known to me, I present a small synopsis below.