Dichotomius (Cephagonus) itatiaiaensis, 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 : 2333-2334

5.2. Dichotomius (Cephagonus) itatiaiaensis new species

( Figure 45 (a-e))

Diagnosis. this species is differentiated in the group by the following combined characters: elytral striae and puncture weakly impressed (like D. fissus ); pronotal disc having two to four rounded lobes on anterior portion (like D. ascanius and D. bicuspis ); paramera having distinct longitudinal excavation (dorsal and lateral view); larger males reaching 17 mm; distance between triangular projections on female sixth ventrite equal to 1/10 of ventrite length ( Figure 9 (c-d)).

● HOLOTYPE (male): BRASIL: Rio de Janeiro. Itatiaia. PARNA Itatiaia. 22³25 ʹ 01 ʹ ’ Sı 48³38 ʹ 35 ʹ ’ Wı 1850 m. Pitfall. 23-xii-2011. C Araújo & C. Andrade [at CEMT].

● PARATYPES: same data of Holotype [5 ƋƋı 11 ♀♀ at CEMT] .

Description. colour: blackı shiny. Head: fronto-clypeal surface smooth. Inter-ocular space with fine punctures interrupted medially. Gena border slightly curved inward. Cephalic horn rounded at apex. Pronotum: anterior portion with a wide central emargination with a pair of weak knobs delimiting pronotal disc anterior margin; pronotal disc smoothı shiny. Posterior margin with a single row of ocellate punctures. Posterior angle excavated and with groups of 5 ocellate punctures. Metasternum: sides and anterior portion of anterior lobe with ocellate setigerous puncturesı setae shortı with similar size to those on legs. Elytra: striae weakly impressed with weak punctures. Punctures separated by twice their diameter. Puncture on basis expanded forming a small fovea. Interstriae flatı lacking microsculpture. Abdomen: punctures of each ventrite anterior margin interrupted medially. Sides of ventrites 1 – 5 with groups of 8 – 15 setigerous punctures. Aedeagus ( Figure 45 (a-e)): dorsallyı having longitudinal excavation taking whole paramaera length; apexes roundedı convergent. Laterallyı subtle declivity. Posterior margin with a narrow ‘ u ’ shape emargination near phalobasis junction. Ventrallyı basis with wide lateral excavations. Basis of subgenital plate acuteı advancing towards phalobasisı apically emarginated.

Morphological variation. males BL: 11 – 17 mmı PW: 7 – 11 mm. Genitalia comparison allowed us to conclude that smaller males do not have a central emargination delimiting pronotal disc and cephalic horn consists of a low tubercle. Females BL: 11 – 16 mmı PW: 7 – 11 mm. Distinguished from males as follows: Head: fronto-clypeal surface transversely wrinkledı interocular space with coarse punctures interrupted medially. Cephalic carinae produced in a single tubercle. Clypeo-genal angle very obtuse (160³); clypeo-genal margin very thick. Pronotum: simply convexı punctures weaker than on males but following same distribution pattern. Elytra: striae deeply impressedı punctures separated by twice their diameter. Basis with strong blue sheen. Abdomen: sixth ventrite with subtle central emargination – distance between triangular projections equal to 1/10 of ventrite length ( Figure 9 (c-d)). Disc with very fine puncture medially (viewed under 30x magnification).

Etymology. named after the type locality.

Distribution. Brazilian Atlantic Forestı higher altitudes in the municipality of Itatiaiaı state of Rio de Janeiro State ( Figure 44 ).

Etymology. Itatiaia is a Brazilian municipality in the state of Rio de Janeiroı where the holotype was collected.

Figures

Figure 9. (a) Abdominal ventrites of a male of D. spadiceus. (b) ventrites of a female of D. spadiceus. (c) abdominal ventrites of a female of D. itatiaiaensisı (d) detail of C; (e) abdominal ventrites of a female of D. fissus. (f) Adbominal ventrites of a female of D. reichei. (g) Abdominal ventrites of a female of D. lucianomourai.

Figure 44. Distribution map of D. spadiceusı D. lucianomourai and D. itatiaiaensis.

Figure 45. D. itatiaiaensis: (a) male dorsal habitus; (b) female ventral habitus; (c) paramera dorsal view; (d) paramera ventral view; (e) paramera lateral view.