Dichotomius (Cephagonus) tissianiae, Nunes & Vaz-de-Mello, 2019

Nunes, Rafael V. & Vaz-de-Mello, Fernando Z., 2019, Taxonomic revision of Dichotomius (Cephagonus) Luederwaldt 1929 and the taxonomic status of remaining Dichotomius Hope 1838 subgenera (Coleoptera: Scarabaeidae: Scarabaeinae: Dichotomiini), Journal of Natural History 53 (37), pp. 2231-2351 : 2327-2328

3.21.: Dichotomius (Cephagonus) tissianiae new species

( Figure 40 (f-j))

Diagnosis. separated from other species in the quadraticeps group by the following combined characters: males cephalic carina rounded at apex (as D. bicuspis ); males pronotum with a central-rounded lobe with two lateral emarginations on anterior portion (as D. reichei ); head dorsal surface striated and paramera apexes strongly flattened apically.

● HOLOTYPE (male): BRASIL: Mato Grosso. Santo Antônio de Leverger. São Vicente da Serra . 15³49 ʹ 42 ” Sı 55³25 ʹ 11 ʹ ’ W. Gallery forest. Human faces. 18-iii-2001. AS Tissiani [at CEMT ].

● PARATYPES: BRASIL: Mato Grosso. Chapada dos Guimarães. Fazenda Aurora. Luz. 20- x-2009. FR Fernandes [1 Ƌ at CEMT]; Juara. 15-xi-2008. LT Schrader [1 Ƌ at CEMT].

Description (Holotypeı male). BL: 20 mmı PW: 12 mm. Colour: blackı shiny. Head: frontoclypeal surface slightly striated. Striation stronger towards genae. Gena borders slightly curved inward. Cephalic carina longer than wideı conical with rounded apex. Pronotum: disc shinyı lacking punctures and having a central-rounded lobe with two lateral emarginations on anterior portion. Region adjacent to eyes with coarse deeply impressed punctures. Posterior margin with a single row of ocellate punctures. Metasternum: sides and margins of anterior lobe covered by long hair. Anterior portion of anterior lobe glabrous. Setigerous punctures equally spaced at sides. Elytra: striae weakly impressed having very discrete puncture (viewed under 30x magnification) spaced by three to four times their diameter. First interstriae (near elytral suture) convex in relation to other interstriae which are almost flat. Interstriae disc with dark brown colourı lacking microsculpture with very fine puncture (20x). Abdomen: sides of each ventrite excavated near anterior margin and with concentrated ocellate punctures. 1st ventrate with 5 setae on each side; other ventrite having very scattered and short setae evenly spaced on sides. Puncture of each ventrite interrupted medially as well as groove along the posterior margin of sixth ventrite. Aedeagus ( Figure 40 (h-j)): dorsallyı paramera apexes roundedı strongly flattenedı convergent; longitudinal excavation absentı basal elliptical excavation present. Laterallyı abrupt declivity from basis towards apex; lacking excavation; posterior border near phalobasis with rounded excavation. Ventrallyı central portion of basis advancing as a rounded lobe beneath phalobasis junction; sclerotised portion of subgenital plate taking almost whole ventral paramera surface; strongly excavated.

Morphological variation. male BL: 17 – 20 mmı PW 10 – 12 mm. Comparison of male genitalia allowed us to find a strange phenotype for this species. Despite the genitalia is exactly the same of the larger maleı a smaller male from Chapada dos Guimarães (BL = 17 mmı PW = 10 mm) bears a transversal low cephalic carinaı lacks pronotal lobes and elytral interstriae has chagrinated microsculpture. A more detailed study of this species may reveal if this male in fact is a D. tissianiae variation or if it is a new species. Since we did not find such evidenceı this specimen is included in the type series of this species.

Distribution. Brazilı state of Mato Grosso ( Figure 36 ).

Etymology. named our friend and entomologist Dr. Ana Sílvia Tissiani (Universidade Federal de Mato Grossoı Brasil)ı who collected the holotype.

Figures

Figure 36. Distribution map of D. ricardosilvaiı D. marcoscarvalhoiı D. furtadoiı D. barbaraeı D. tissianiaeı D. eması D. frizzasae and D. candangoi.

Figure 40. D. tissianiae: (a) larger male dorsal habitus; (b) smaller male dorsal habitus; (c) paramera dorsal view; (d) paramera ventral view; (e) paramera lateral view. D. ricardosilvai: (f) larger male dorsal habitus; (g) smaller male dorsal habitus; (h) paramera dorsal view; (i) paramera ventral view; (j) paramera lateral view.