Dichotomius guaribensis
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Ordo: Coleoptera
Familia: Scarabaeidae
Genus: Dichotomius
Name
Dichotomius guaribensis Valois & Vaz-De-Mello & Silva, 2017 – Wikispecies link – Pensoft Profile
- Dichotomius guaribensis Valois, Marcely C., 2017, Zootaxa 4277: 518-520.
Etymology
Etymology. The species name is a toponym in apposition referring to the type locality.
Materials Examined
Brazil Rio Triunfo Pitfall & M. I. M. Hernandez Brazil Mamanguape A. A. Endres Brazil Mamanguape A. A. Endres Brazil Mamanguape A. A. Endres Brazil Rio Triunfo M. I. M. Hernandez Brazil Paraiba Joao Pessoa & A. A. Endres Brazil Natal Parque das Dunas & M. E. Maldaner Brazil Natal O. Camara Brazil Brejo Novo Fernando Silva
Diagnosis
Diagnosis.Dichotomius guaribensis sp. nov. is similar D. gilletti sp. nov. and D. catimbau sp. nov. in having the disc of the pronotum with ocellate punctures (Figs 6 d, 7d, 9d) and the disc of the pygidium smooth, with ocellate punctures only on the margins (as in Fig. 11 h). It can be distinguished from D. gilletti sp. nov. by the surface of elytral interstriae lacking rough, being almost smooth. It can be distinguished from D. catimbau sp. nov. by the metasternum on its anterior lobe with dense ocellate punctures, margins of punctures touching (Fig. 6 e); margin of lateral lobes of the metasternum, near metepisternum, with sparse ocellate punctures. The shape of the parameres and lamella copulatrix are also diagnostic: in lateral view, the dorsal margin of parameres are straight on basal half (Fig. 6 f); in dorsal view, the basal portion of parameres slightly wider than apical portion (Fig. 6 h); and lamella copulatrix with subretangular projection; lateral portion of projection abruptly curved inward medially (Fig. 10 e).
Description
Description. Length:11–14 mm. Body black with glossy bluish sheen on pronotal and elytral surface (Fig. 6 a). Head: clypeal surface with ocellate punctures only on anterolateral portion; central portion smooth (Fig. 6 b). Clypeofrontal suture with one central and conical horn; and two weak and smooth knobs on interocular portion of head, closer to the eye (Fig. 6 b). Dorsal interocular surface with slight depression on its central portion; surface covered by dense ocellate punctures, separated from each other by less than their diameter (Fig. 6 b). Pronotum: slightly convex in lateral view. Disc with small and sparse ocellate punctures, separated from each other by three times their diameter (Fig. 6 d); punctures larger, denser and separated from each other by less than their diameter on anterolateral portion and on anterior margin (Fig. 6 d). Posterior margin with a row of large ocellate punctures. Margination of posterior edge with large and dense punctures. Hypomera: posterolateral portion with elliptical punctures, some punctures setigerous. Metasternum: lateral portions of metasternum with setigerous punctures, separated from each other by approximately twice their diameter. Elytra: surface of interstriae convex, punctures noticeable only at high magnification. Legs: ventral surface of profemur with elongated, sparse and setigerous punctures on apical third. Posterior margin of meso and metafemur with longitudinal sulcus on apical half; sulcus approximately one-eighth as wide as the femur (Fig. 11 c). Ventral surface of mesofemur with setigerous punctures on apical half. Row of setae toward the body on ventral surface of mesotibia restricted to apical third of tibia (as in Fig. 11 f, arrow). Abdomen: surface of sternites with a single medial row of ocellate punctures; lateral portion densely punctate on anterior half. Length of male medial portion of sixth sternite half that of the fifth. Pygidium: slightly wider than long. Disc smooth, ocellate punctures just near the margin (as in Fig. 11 h). Aedeagus: parameres subtriangular, 2/3 as long as the phallobase (Fig. 6 f–h). [lateral view] — Ventral margin of parameres slightly curved inward on apical two-thirds (Fig. 6 f). [ventral view] — inner margins of parameres slightly curved outward (Fig. 6 g). [dorsal view] external margin of parameres slightly expanded toward apex (Fig. 6 h). Endophallus: lamella copulatrix — Projection subretangular; superior portion slightly curved outward. Secondary sexual characters: females differ from males by: clypeal teeth more acute (Fig. 6 c); anterior surface of clypeus with well-defined transversal ridges (Fig. 6 c); medial portion of sixth sternite as long as the fifth.
Discussion
Remarks. Specimens from Reserva Biológica Guaribas, Mamanguape, Paraíba, were referred to as D. sericeus (Harold, 1867) (Endres et al., 2007). We have examined some of these specimens and after analysis we concluded that they correspond to the species described here as D. guaribensis sp. nov. According to Endres et al. (2007), this species is abundant in Reserva Biológica Guaribas, corresponding to approximately 50% of specimens recorded in the Tabuleiro Nordestino (coastal tableland of the northeast) and Atlantic rainforest areas.
Taxon Treatment
- Valois, Marcely C.; Vaz-De-Mello, Fernando Z.; Silva, Fernando A. B.; 2017: Taxonomic revision of the Dichotomius sericeus (Harold, 1867) species group (Coleoptera: Scarabaeidae: Scarabaeinae), Zootaxa 4277: 518-520. doi
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