Athyreus arretado Celante & Carvalho & Jahyny & Araújo & Santos 2024, new species

Athyreus arretado Celante & Carvalho, new species Fig. 2A, 3A–G, 4A–F, 5A http://zoobank.org/ urn:lsid:zoobank.org:act: 1CA6E1C3-F6DE-452F-A177-AA 2730DEC2 CF Type material. Holotype male, BRAZIL: “24 L 240709 8960576, BAHIA, Casa Nova, Areia Grande, LMS16AB, 27.i.2023, Celante, G. leg.” (MFCE014265, deposited at MFCE) (Fig. 3A–H). Paratype male, BRAZIL: “24 L 241461 8960156, BAHIA, Casa Nova, Areia Grande, LMS98AB, 17.ii.2024, Celante, G., Gurgel, M., Melo. A, Silva-Junior, A. legs.” (MFCE018115, deposited at INPA). Diagnosis. This species can be distinguished from other Athyreus species by the following combination of characters: clypeal horn absent (Fig. 3A, C–E, G); pronotum with only one horn in the middle of anterior margin (Fig. 3A, C–E, G); presence of a pair of central carinae that begin in the anterior region of the pronotum that extend divergently to the medial region, where they change direction, extending convergently to the posterior region where they curve towards the center of the pronotum, giving a “J” pattern (Fig. 3A, D); protibia with six teeth on outer margin (Fig. 3D, G). Description. Holotype. Male (Fig. 3A–H). Length: 23.6 mm, width: 14.5 mm. Color. Dorsally brown, head and pronotum reddish brown, elytra dark brown; laterally slightly lighter; ventrally orange-brown. Head. Labrum 2.3x wider than long, in dorsal view, lateral margins rounded, anterior margin concave, surface irregularly punctate (Fig. 3A, E). Clypeus without a central horn (Fig. 3A, C–E, G); in dorsal view, presence of a pair of carinae that originate, posteriorly, close to the height of the insertion of the antennae, extending obliquely towards the center of the anterior margin of the clypeus, without being connected (Fig. 3E); in lateral view, central region elevated, with a triangular appearance, approximately the height of the apex of the mandibles (Fig. 3C). Gena, in dorsal view, anteriorly and posteriorly concave; ocular canthus with rounded apex; carinate margins, starting at the clypeal carina and surrounding the laterodorsal margin of the head to the anterior region (Fig. 3E). Front, in dorsal view, with a pair of carinae that begin at the proximal anterior angle of the gena and extend obliquely towards the vertex, without meeting (Fig. 3E). Pronotum. Middle of anterior margin with a single horn, directed upwards (Fig. 3A, C–E, G); posterior region with a groove extending from behind the central horn to a concavity located in the anterior region (Fig. 3A, G); a carina extends around the outer margins, thicker in the posterior region (Fig. 3A); a pair of central carinae on disc extend from the base of the anterior pronotal horn divergently to the medial region, where they change direction, extending convergently to the region posterior where they curve towards the center of the pronotum giving a “J” appearance (Fig. 3A, D, G); median region of the central carinae with a tooth in lateral view (where the carinae change direction, from divergent to convergent) (Fig. 3C); posterior region with two trapezoidal lobes in frontal view, slightly exceeding the level of the elytra (Fig. 3D); cavity of the procoxae connected to the most anterior margin of the pronotum by a carina (Fig. 3F). Elytra. Six striae between the base of the elytra and the humeral callus (Fig. 3A). Legs. Protibiae with five well-defined teeth on the outer lateral margin, elongate apical tooth, teeth 2–5 triangular, gradually decreasing as they move away from the distal region, a reduced sixth tooth is present in the proximal region (Fig. 3D, G). Aedeagus. Parallel and separate parameres, regularly curved from the base to the apex, divergent; in lateral view, parameres flattened and hooked. (Fig. 4A–F). Variation. No variation noted between the holotype and the paratype. Female. unknown. Etymology. The species is named in reference to a typical expression from the northeastern region of Brazil. The term “arretado ” can have several meanings, including positively highlighting characteristics of people, objects, and places, and can be used as a synonym for beautiful, impressive, and spectacular. Ecology. The only known specimens of this species were attracted by flashlights and flew relatively close to the ground, approximately 60 cm high. Distribution. The new species is only known from the type locality in the São Francisco River Sand Dunes Ecoregion (-9.3952, -41.3610, Casa Nova Dunes Complex, Bahia, Brazil). (Fig 1, 2A, 5A). Taxonomic position. Athyreus arretado is a representative of the A. aeneus species group and differs from all species belonging to the A. bifurcatus species group and A. chalybeatus species group by the presence of a complete longitudinal sulcus, which begins at posterior base of anterior pronotal horn, and extends to the posterior region of pronotum (Fig. 3A, G). The species groups established by Howden & Martínez (1978) facilitate the identification key and the recognition of species. However, the phylogenetic validity of these species groups has never been tested and were questioned by Howden (1999), who noted that the males of Athyreus fritzi Howden, 1999 and A. langeri Howden, 1999 fit in the A. aeneus species group, while females fit in the A. chalybeatus species group. Taking this discussion into account and considering the morphological similarity of A. langeri and the recently described species A. joseferreirai, we consider the latter as a member of the A. aeneus species group and included it in the updated key below.