Eutrichillum Martinez 1969
Creators: name: Vaz-De-Mello, Fernando Z.
Publisher: name: Zenodo
Year: 2008
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Scarabaeidae
Eutrichillum

description: 4. Eutrichillum Martínez, 1969 new status   
 Trichillum (Eutrichillum): Martínez 1969: 121; Ratcliffe 1980: 340–341; Martínez 1989: 60; Solís & Kohlmann 2003: 10, 12.   
 Trichillum (Eutrichillum) Martínez, 1967 [sic]: Vaz-de-Mello, 2000: 195.   
 Diagnosis: Head with clypeogenal margin strongly incised (causing clypeus and genae to be separately rounded) and clypeogenal suture strongly marked, in some cases joining the clypeofrontal suture and forming a very feeble acute carina, insconspicuous at midlength (Fig. 49). Pseudoepipleura strongly narrowed posteriorly.   
 Description: Length 2.7–4.6 mm, body short oval (Fig. 19), color grey to black with feeble metallic sheen, or completely metallic green to red. Clypeus with two strong teeth, separated by narrow U-shaped emargination, mesal border of tooth almost parallel; clypeus external to teeth regularly rounded, separated of genal border by incision, genal border being separately strongly and regularly curved. Clypeofrontal and clypeogenal sutures strongly indicated and united, being frequently cariniform at least near junction. Eyes dorsally as wide as third to fifth of its length, interocular width 8 to 12 times eye width (Fig. 49). Pronotum lacking anterior or posterior beads; lateral pronotal callosity well defined and elongate; disc centrally with uniform elongate setose punctures; pronotum separated of hypomeron by complete carina. Hypomeron with strong lateral longitudinal carina; mesoepimeron anterior transverse carina present; metasternal disc with round simple setose punctures. Elytral interstriae with only one row of setose punctures, situated laterally in interstriae one and two, and mesally in the remaining interstriae; interstriae flat all along, slightly deeper and widened posteriorly. Pseudoepipleura strongly narrowed posteriorly from about metacoxa, forming strong marginal angle; glabrous all along. Protibiae with three very strong teeth, distributed along apical three-fifths, denticulate basally, with ventral scale-like setae. Mesofemur and metafemur as wide as third to fourth of their length, tibiae apically as wide as third to fourth of their length. Metatarsi with basal tarsomere longer than second tarsomere. Parameres with apex strongly deflexed, forming a strong dorsal hump at apical third, with strong outer subquadrate flat apical lobes directed ventrally (Fig. 50). Internal sac with pseudoflagellum highly sclerotized, positioned spirally inside phallobase, but straightened when extruded, with wide triangular base with one to three strong teeth and pointed apex, with the entire body canaliculate longitudinally, and large triangular plate accessory lamella; coxites not heavily sclerotized, large. Spermatheca C-shaped, sinuate in the middle, but with strongly narrowed and spiral-shaped base and apex (Fig. 14), duct very long, spirally shaped and not sclerotized.   
 Sexual dimorphism: Males have proclaws strongly bent mesally and apical tarsomere modified in order to receive them (Fig. 51); protibial apicomesal tooth present in males and apically directed; abdominal disc flatter, pygidium less transverse, and metasternum flatter than in females.   
 Type species: Trichillum boucomonti Saylor, 1935 = T. hirsutum Boucomont, 1928 (original designation) = Eutrichillum hirsutum Boucomont, 1928, new combination.   
 Distribution: A group of species (of which two already described) inhabit South American lowlands, east of the Andes as far south as Buenos Aires in Argentina; one species in Costa Rica. This is a very disjunct distribution, corresponding on one side the entire Chacoan, Parana and Amazonian subregions, and on the other, some localities in Eastern Central America province of the Caribbean subregion.   
 Remarks: Species of this genus are mostly necrophagous and frequently attracted to lights. The genus belongs to a clade that includes Feeridium, Degallieridium, Besourenga and Trichillum (see above under Besourenga), and is characterized by the following synapomorphies: clypeus and gena separately rounded; clypeogenal and clypeofrontal sutures strongly indicated; parameres forming dorsal hump at apical third; pseudoflagellum hosted by internal sac spirally and straightened when extruded; spermatheca with base and apex strongly narrowed and spiral shaped.   
 Composition: Apart of the type species, the genus contains Eutrichillum hystrix (Arrow, 1931), new combination (described as Trichillum), E. arcus (Solís & Kohlmann, 2003), new combination (described as Trichillum), and at least five new species currently being described.   
 Material examined:
description: Published as part of 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, pp. 1-75 in Zootaxa 1955 on pages 22-23