Aegognathus Leuthner, 1883

Ríos-Málaver, Juan Sebastián Dueñas Cáceres ı Cristóbal & Grossi, Paschoal Coelho, 2019, Taxonomic contribution on the Andean species of Aegognathus (Coleoptera: Lucanidae) with two new species from Colombia and Peru, Journal of Natural History 53 (35), pp. 2145-2164 : 2147-2148

Aegognathus Leuthner, 1883 .

Type species: Aegognathus waterhouseiı 1883 , by monotypy

Description male

Colour: Variable, entirely black, with small dark-red areas, in some cases presenting red to orange tones along whole body; elytra sometimes with bluish reflections, and covered by yellow small scales like setae. Head: shorter than wide; surface at first view smooth, shagreened; anterior margin emarginate at the median region; usually with almost parallel lateral margins. Antennae 10 segmented, lamellae with yellowish setae over distal region. Ocular canthus, covering only the first third of eyes. Mandibles, of major males strongly curved inwards, with a long medial internal tooth directed upward, reduced or absent in small males; apex acuminate to truncate, some species with wavy inner margin; one species ( A. aguirei ) with broad, less curved mandibles which lack a distinct median tooth. Pronotum: Anterior margin slightly emarginate, margins completely bordered, interrupted on the anterior margin medially, with a continuous band of yellowish setae; anterior angles rounded to acute, sides almost straight, narrowing near the posterior angles; surface shagreened, disc usually flat, weakly concave. Elytra: Surface strongly and uniformly punctate, punctures large to coarse, dense to somewhat contiguous, with white to yellow simple or dendritic setae, sometimes with some longitudinal costae, never smooth. Epipleuron punctures moderate to large. Legs: Protibiae showing variable number of external teeth but presenting at least two strong distal ones; one apical spur, glabrous. Mesotibiae and Metatibiae with four apical teeth, inner spur slightly longer and more slender than the external one; sometimes mesotibiae with 1 – 3 median acuminate teeth; metatibiae usually with one median acuminate tooth only. Venter: Mentum trapezoidal, granulate dense, usually with small yellowish appressed setae, anterior margin not differentiated. Gena punctate or minutely punctate, showing a posterior carina that clearly delimits its posterior margin. Prosternum granulate with yellowish appressed setae; anterior and posterior margins showing a fringe of yellowish setae. Mesoventrite punctate with appressed yellowish setae, medially. Metaventrite moderately punctate over the median region, with yellowish appressed setae that become denser laterally. Discrimen present as a longitudinal suture along the metaventrite. Abdominal ventrites usually bordered, sometimes with a discrete to distinct carina along lateral margins; puncture size variable, dense to sparse. Genitalia: Genital capsule simple with dark and translucent regions; aedeagus shape usually subtriangular; basal piece with a translucent area over the disc; median lobe elongate, sides parallel, never folded, with an ‘ H ’ to ‘ X ’ shaped cross bar, never as a transverse bar; everted internal sac flat to cylindrical, apex generally cylindrical, darkened by minute spicules.

Description female

Colour: as males but always presenting darker tones along the whole body. Head: Shape smaller than males, subquadrate, narrower than the pronotum; strongly punctate; mandibles subequal, presenting a variable transverse tooth. Pronotum: Surface strongly and uniformly punctate, angles more distinct, anterior ones usually acute, posterior ones somewhat rounded; anterior margins reaching the posterior region of head. Elytra: surface strongly punctate, punctures contiguous, coarse with yellowish erect setae, becoming denser posteriorly. Legs: General aspect stronger, less slender, with a variable number of external teeth on protibiae. Venter: Punctures more distinct, and almost uniformly distributed along entire ventral surface; discrimen generally more distinct than in males. Genitalia: Gonostyli symmetric, slightly prolonged laterally with somewhat truncate posterior margin presenting some scattered setae. Accessory gland, broad, almost as large as the gonocoxites together. Bursa copulatrix slightly wider at base, getting narrower distally, sometimes uniformly broad, cylindrical. Spermatheca narrow, C-shaped with sclerotised dilated apex. Spermathecal gland absent. Supra anal projection subtriangular, with acuminate to rounded apex.

Distribution of Andean species

Colombia, Ecuador, Peru, along the Páramo province ( Morrone 2015)

Remarks. The genus currently includes 10 species described for Colombia, Ecuador, Peru and Brazil, the Peruvian and Ecuadorian species being better known or more frequently collected. The first described species A. waterhousei was registered for Chanchamayo in Peru, subsequently, other species were described for Colombia ( Van De Poll 1886), Brazil ( Luederwaldt 1935), Ecuador ( Bartolozzi et al. 1991) and other regions of Peru ( Arnaud and Bomans 2004, 2006a, 2006b, 2007).