Aegognathus waterhousei Leuthner, 1883

Cáceres, Juan Sebastián D. & Grossi, Paschoal Coelho, 2023, Taxonomic revision of Aegognathus Leuthner, 1883 (Coleoptera: Lucanidae), Journal of Natural History 57 (9 - 12), pp. 557-595 : 567-570

Aegognathus waterhousei Leuthner, 1883 , by monotypy.

Diagnosis

Body colour from entirely black to body surface with reddish and bluish tones with black spots. Males, head transverse and emarginate; ocular canthus covering first third of eyes; mandibles strongly curved inwards with one median tooth, mandibles straight in one species, in that case head wider than elytra. Pronotum with a longitudinal groove at disc, anterior margin with a continuous fringe of setae. Head and pronotal surface shagreened, elytral surface with coarse punctures, dense to contiguous. Ventrally with variable size of punctation, almost uniform along prosternum, meso- and metaventrite. Abdominal ventrites laterally carinate. Genitalia mostly subtriangular, sometimes elongate and cylindrical, with long everted sac, flat and short in one species; dorsal cross bar ′X̍ shaped. Females same as males except for presenting darker colour tones, reduced heads, short mandibles, asymmetrical with acuminate apex and one laminar tooth. Body surface with coarse, dense to contiguous punctures.

Description – male

Colour: Variable, entirely black, with small dark red areas, in some cases presenting red to orange tones along body; elytra sometimes with bluish reflections, and covered by yellow small setae. Head: Shape transverse; surface, shagreened; anterior margin emarginate medially; 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 strongly curved inwards, with a long medial internal tooth directed upwards, reduced or absent in small males; apex acuminate to truncate, some species with wavy inner margin; one species ( A. aguirei ) with wide, flat, less curved mandibles, lacking the median tooth. Pronotum: Anterior margin slightly emarginate, margins completely bordered, interrupted on the anterior margin, 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 smooth 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 slenderer than the external one; mesotibiae sometimes with 1–3 median acuminate teeth; metatibiae usually with one median acuminate tooth only. Venter: Mentum trapezoidal, punctate, usually with small yellowish appressed setae, anterior margin not differentiated. Gena punctate, showing a posterior carina that clearly delimits its posterior margin. Prosternum punctate with yellowish appressed setae; anterior and posterior margins showing a fringe of yellowish setae. Mesoventrite punctate with appressed yellowish setae, concentrated 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 weak to distinct carina along lateral margins; puncture size variable, with a dense to sparse distribution. 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 ′H̍ to ′X̍-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 in males but always presenting darker tones along the whole body. Head: Shape subquadrate, smaller than males, narrower than the pronotum; strongly punctate; mandibles asymmetrical, presenting a transverse tooth with variable shape. 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 symmetrical, slightly prolonged laterally with somewhat truncate posterior margin presenting some scattered setae. Accessory gland wide, almost as large as the gonocoxites together. Bursa copulatrix slightly wider at base, becoming narrower distally, sometimes uniformly wide, cylindrical. Spermatheca narrow, ′C̍ shaped with sclerotised dilated apex. Spermathecal gland absent. Supra anal projection subtriangular, with acuminate to rounded apex.

Distribution

Colombia, Ecuador, Peru. South American Transition Zone and Brazilian sub-region (Pacific and South Brazilian dominions) ( Morrone et al. 2022).

Remarks

Aegognathus Leuthner , in its new sense, includes nine species distributed in Colombia (two species), Ecuador (one species) and Peru (seven species). Aegognathus leuthneri Van de Poll, 1886 is reported from both Colombia and Ecuador.

For the key to Aegognathus species, see Cáceres et al. (2019).