Aegopsis diceratops Sobral & Grossi, new species

(Fig. 2–9, 11)

Diagnosis. Males: clypeus subrectangular, apex convex (Fig. 2C); ocular canthi anteriorly protruding, posteriorly acute (Fig. 3C); internal lobe of mandibles partially covered by mesal brush (Fig. 5B); mentum subtrapezoidal with apical corners carinate (Fig. 5E); parameres, in ventral view, with apex acute, ventral carina basally round, inferior edge of parameres deeply concave (Fig. 6E). Females: clypeus trapezoidal, punctures absent on middle of vertex (Fig. 7C); frons with two distinct tubercles (Fig. 7D); mentum subtrapezoidal, apical corners with a weak carina (Fig. 8E).

Holotype description, male. Color: Surface lustrous; dorsum, venter and appendages, dark brown with a weak metallic shine (Fig. 9A). Head: Frons moderately punctate; punctures moderate in size, becoming larger and mixed with smaller punctures posteriorly to clypeus. Cephalic horns moderately punctate, rugopunctate dorsally on outer side; punctures small, becoming larger near base. Clypeus densely punctate, punctures larger and coalescent basally, becoming smaller and fine apically; clypeus subrectangular, apex convex (Fig. 2C). Ocular canthi anteriorly protruding, posteriorly acute, with a few setae posteriorly; anterior carina disrupted near cephalic horns base (Fig. 3C). Mouthparts: Labrum setose, almost semicircular, laterally acute (Fig. 4D). Mandibles subtriangular with two prominent teeth apically and two ventral carina; in ventral view, apical protuberance absent, internal lobe partially covered by mesal brush (Fig. 5B). Maxilla with galea subtriangular, teeth absent, external edge basally projecting, crossing external edge of stipes, anterior margin of external edge straight; maxillary palpomere IV four times longer than wide; sensorial area densely striate (Fig. 4E). Mentum subtrapezoidal, apical corners with carina (Fig. 5E). Prothorax: Pronotum bordered, disc weakly convex and distinct punctate. Thoracic horn strong, apex slightly downturned. Punctures smaller from posterior margin of pronotum to apex of horn, becoming larger and denser on sides (Fig. 2D). Anterior angles and lateral edges of horn completely wrinkled. Scutellum: Subtriangular; punctures strong anteriorly and medially, setose anteriorly. Elytra: Form 1.7 times longer than wide. Surface glabrous, densely covered by large ocellate punctures, microsculpture slightly wrinkled. Elytral punctures generally irregular, with distinct sutural striae; striae not impressed, punctures small. Humeral umbone weak, apical umbone distinct, round, not crossing elytral external edges. Legs: Protibial surface rugopunctate dorsally, with two setose striae; protibia with three well-developed external teeth posteriorly decreasing in size, punctate on external edges of teeth. Pygidium: Form 2.5 times wider than longer, strongly convex. Disc and anterior edge glabrous, hirsute laterally and on posterior edge; densely wrinkled on edges; larger and denser punctures medially. Genitalia: Parameres, in dorsal view, as in Fig. 6F; in lateral view, thicker than apex of phallobase, lateral carina strongly curved at base (Fig. 6D); in ventral view, apex acute, ventral carina basally round, inferior edge of parameres deeply emarginate (Fig. 6E).

Measurements of holotype. Body length: 29.4 mm. Cephalic horns length: 6.4 mm. Elytral length: 15.9 mm. Elytral width: 8.8 mm. Pronotal width: 13.2 mm. Protibial length: 7.9 mm.

Paratypes variation, males. Only minor males were found. Minor males (Fig. 9B) with cephalic horns as long as vertex. Thoracic horn short, tuberculate, not crossing anterior margin of pronotum. Ocular canthi anteriorly rounder, but still protruding. Punctures of pronotum larger and denser than holotype.

Measurements of male paratypes. Body length: 18.1–22.8 mm. Cephalic horns length: 1.1–1.6 mm. Elytral length: 12.3–12.6 mm. Elytral width: 6.7–7.1 mm. Pronotal width: 9.5–10.9 mm. Protibial length: 5.8–6.2 mm.

Paratype description, females. Females as males in general aspect except the following (Fig. 9C). Head: Cephalic horns absent. Frons with two strong tubercles (Fig. 7D). Clypeus trapezoidal, slightly concave from frontoclypeal suture to apex (Fig. 7C). Surface with punctures larger and denser, especially on clypeus, wrinkles in front of tubercles; punctures absent on vertex near the pronotal margin. Ocular canthi strongly convex anteriorly, concave posteriorly (Fig. 3D). Mouthparts: Labrum more convex anteriorly, sides round. Mandibles and teeth shorter, middle part of mesal brushes more concave (Fig. 8B). Maxilla shorter, galea and stipes less hirsute, maxillary palpomere IV 2.9 times longer than wide, sensorial area broader and shorter, striae sparser and almost indistinct (Fig. 4F). Mentum shorter, apex longer, less hirsute, carina not touching anterior angles (Fig. 8E). Pronotum: Weakly convex; prothoracic horn absent; punctures large and dense, wrinkles absent. Scutellum: Surface more punctate, punctures larger. Pygidium: Convex, slightly concave near apex, apex compact. Strongly hirsute, laterally with long bristles, short bristles at middle. Coalescent punctures denser medially, annular punctures near apex.

Measurements of female paratypes. Body length: 21.1–25.2 mm. Elytral length: 14.2–15.5 mm. Elytral width: 7.3–8.2 mm. Head length: 3.2–3.3 mm. Pronotal width: 10.3–10.6 mm. Protibial length: 5.7–6.3 mm.

Geographic distribution. Brazil: northwestern Minas Gerais (Fig. 11).

Material examined. Holotype male dissected, labeled: a) “ BRASIL: Minas Gerais. / Buritis. Faz. Querência. / 15°10'50.4''S;46°32'20.1'' / W. 978m. 18-X-2013. / C.M.Oliveira ”; b) “ Aegopsis diceratops n. sp. / male HOLOTYPUS / R. Sobral & P.C. Grossi det. 2018”. Paratypes: 3 males and 3 females with same data as holotype . Holotype and one female paratype at CERPE, one male and one female paratype at CEMT, one male and one female paratype at EPGC.

Etymology. From the Greek, “ Di ” meaning “two”, “ keras ” meaning “horn” and “ ops ” meaning “face”, in reference to the two cephalic horns. This name is an adjective in the nominative singular.

Remarks. Aegopsis diceratops is known from Brazilian Cerrado areas, in a rupestrian field area, at 900 m of elevation, from the northwest of Minas Gerais state. This species is most similar to Aegopsis chaminadei Dechambre, 1999 as both species have three teeth on protibia, the clypeal apex round, and the same shape of ocular canthus. However, A. chaminadei occurs in an intersection area of Peruvian Yungas and Southwest Amazon moist forests, at 450 m of elevation, from southeastern Peru (Dechambre 1999; Dinerstein et al. 2017). Also, the shape of parameres and mentum is very distinct. Whereas A. chaminadei has the apex of parameres almost as long as the base of parameres (Fig. 12A) and the mentum round (Fig. 12B), A. diceratops has the apex two times longer than base of parameres (Fig. 6F) and mentum subrectangular (Fig. 5E).

Although the distribution of A. diceratops is geographically close to Brasília municipality (one of the locality records of A. bolboceridus), males of both species can be easily distinguished by the clypeal apex, which is convex (Fig. 2C) in the new species and truncate (Fig. 2A) in A. bolboceridus . Also, A. diceratops differs by having the ocular canthi anteriorly protruding (Fig. 3C) and paired carinae on the apical angles of the mentum (Fig. 5E), while in A. bolboceridus the ocular canthi are anteriorly straight (Fig. 3A), and the mentum carinae are absent (Fig. 5D). Females of A. diceratops have a trapezoidal clypeus (Fig. 7C) and strong frontal tubercles (Fig. 7D), while females of A. bolboceridus have a round clypeus (Fig. 7A) and inconspicuous frontal tubercles (Fig. 7B). The morphological differences of these two species, as well as the fact that specimens of A. diceratops were not found in the same localities as A. bolboceridus, may indicate that these two species are geographically separated. In the Brazilian Cerrado, the rupestrian field is a phytophysiognomy that occurs above 900 m on ridges associated with quartzite, arenite and iron ore outcrops (Vasconcelos 2011). Rupestrian fields are similar to islands intercalated by valleys or different phytophysiognomies (i.e., Cerrado fields or peat bogs), so we hypothesize that ancestral lineages of A. bolboceridus and A. diceratops may have been isolated by the Neogene uplift of the Brazilian Plateau and Quaternary climate oscillations, in which the ridges, lowlands, and phytophysiognomies were shaped. This has been observed in some species of lizards (Domingos et al. 2014) and presumed for some species of dung beetles (Nunes et al. 2012).