Trichillidium, 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 : 44-45

16. Trichillidium , new genus

Diagnosis: Clypeus with four variably-shaped teeth, inner pair separated by U-shaped emargination. Laterally to outer teeth clypeal margin concave, continuous with that of gena ( Figs. 93, 95, 97). Elytral striae very strongly impressed apically. Pseudoepipleura gradually narrowed apically, with uniseriate setose punctures and irregular ventral punctures in the anterior half. Protibiae with two to three apical teeth; if three then basal one very small; teeth distributed along apical half or less of tibial margin length. Mesotibiae and metatibiae with dense setae apically and ventrally.

Description: Length 2.7–4.1 mm. Body short oval, with maximum width mesally on elytra ( Figs. 35–36); color grey to black, sometimes with slight metallic sheen. Clypeus with four teeth, inner two separated by wide U-shaped emargination. Laterally to outer teeth,, clypeal margin continuous with genal margin, concave; genal lateral angle projected. Head uniformly convex, with shallow concavities anterior to eyes. Clypeofrontal suture distinct only laterally, clypeogenal sutures indistinct. Eyes, in dorsal view, as wide as third to half of their length; interocular width eight to 12 times eye width ( Figs. 93, 95, 97). Pronotum lacking anterior or posterior beads, laterally with callosity only very feebly indicated; hypomeron separated from pronotum by strong longitudinal carina. Hypomeron with strong lateral longitudinal carina; mesoepimera anteriorly with transverse carina indistinct; metasternal disc covered by small setose punctures. Elytral interstriae flat, with biseriate setose punctures. Striae moniliform, with large coalescent punctures, which are strongly widened and deeper at apex. Pseudoepipleura gradually narrowed apically, with uniseriate setose punctures. Protibiae with two to three teeth (if three then basal one very small), distributed along less than half of tibial length; scalelike setae lacking ventrally. Mesotibiae and metatibiae slender, apical width less than third of tibial length, with very dense setae apically and ventrally, surface difficult to see. Protarsomeres and claws simple. Pygidium elongated, inclined, not exactly vertical. Internal sac with large, thick pseudoflagellum. Coxites large, laminate, triangular and symmetrical. Spermatheca C-shaped, base bulbous, gradually narrowed to acute apex.

Sexual dimorphism: Males with small apicomesal tooth in protibiae, scale-like setae ventrally in protarsi, metasternal disc convex (concave in females), and abdominal disc shorter than in females.

Type species: Pedaridium quadridens Arrow, 1913 = Trichillidium quadridens ( Arrow, 1913) , new combination.

Etymology: Combination of Trichillum and Pedaridium , due to the fact that species included have been originally described in these different genera. This name was also found in some of A. Martínez's identification labels. Gender neutral.

Distribution: Southern Nicaragua to Central Argentina, absent in Western Amazonia, Central and Northeastern Brazil. Exhibits disjunct distribution comprising southern Mesoamerican dominion (Eastern Central America and Western Panamanian Isthmus provinces) and Choco and Western Ecuador provinces in Northwestern South American dominion, in the Caribbean subregion; Amapa and southern Pantanal provinces in the Amazonian subregion; Chaco and Pampa provinces in Chacoan subregion, and Parana Forest in Parana subregion.

Remarks: This genus is undoubtedly related to Bradypodidium (q.v.), and is defined by the following apomorphies: projection of lateral part of gena; convexity of head disc, and shallow concavities anterior to the eyes. This genus has very variable parameral shapes (e.g., Figs. 94, 96).

Composition: Apart of the type species, this genus includes T. brevisetosum ( Howden & Young, 1981) , new combination (described as Pedaridium ), T. caingua ( Martínez, 1974) , new combination (described as Pedaridium with a question mark), T. pilosum ( Robinson, 1948) , new combination (described as Trichillum ), and at least one or two species yet undescribed.

Material examined: