Dichotomius (Cephagonus) arnaudi, 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 : 2312-2313

publication ID	https://doi.org/ 10.1080/00222933.2019.1692088
DOI	https://doi.org/10.5281/zenodo.3671908
persistent identifier	https://treatment.plazi.org/id/C740D609-2A30-BB16-FEFE-E432E55B2D9F
treatment provided by	Valdenar
scientific name	Dichotomius (Cephagonus) arnaudi
status	sp. nov.

Treatment

3.7.: Dichotomius (Cephagonus) arnaudi View in CoL new species

( Figure 33 View Figure 33 (a-d))

Diagnosis. this species is separated from other in the group by the following combined characters: males pronotal disc simply convex with a most central knob on anterior portion (as D. emas ); ventrite glabrous and lacking distinct ocellate puncture along anterior margins; males cephalic process produced in a single tubercle (as D. edmondsi and smaller specimens of D. bicuspis , D. ascanius and D. reichei ); genae borders divergentı posterior angle rounded; paramera having fine carina delimiting basal and longitudinal excavations and sides of elytra sub-parallel in dorsal view (as in D. clypeatus ).

● HOLOTYPE (male): BOLIVIA: Nor Yungas. Caranavari/Carrasco. xii-1991. P Arnaud [ CEMT].

● PARATYPES: same data of Holotype [2 ♀♀ at CEMT]. PERU: Cuzco. San Pedro. 13³03 ʹ 15 ʹ ’ Sı 71³32 ʹ 54 ʹ ’ Wı 1500 m. Cloub Forest. FIT. xi-1999. T Larsen [1 Ƌı 2 ♀♀ at TLpc]

Description (holotype). male: BL: 15 mmı PW: 8 mm. Colour: dark brown to blackı shiny. Head: fronto-clypeal surface smooth with few lateral striations along clypeo-genal groove. Cephalic horn produced in a single central tubercle. Pronotum: simply convexı with a weak knob on anterior portion. Ocellate punctures present on posterior angles. Pronotal disc smoothı shinyı with very fine punctures (viewed under 20x magnification). Anterior portionı adjacent to eyes with coarse weakly impressed 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 deeply impressed having fine punctures spaced by twice their diameter. Interstriae convexı disc smooth with very fine punctures (viewed under 20x magnification). Abdomen: ventrites glabrous and lacking rows ocellate punctures along anterior margin. Groove along the posterior margin of sixth ventrite complete but not concealing the ventrite. Aedeagus ( Figure 33 View Figure 33 (b-d)): Dorsallyı paramere apexes roundedı convergent; longitudinal excavation present taking the whole paramera length; basal-rounded excavation present; fine continuous carina present along paramera delimiting basal and longitudinal excavations. Laterallyı subtle declivity from basis towards apex. Ventrallyı basis with wide excavationı lacing sclerotised portions; subgenital plate emarginated both basally and apically.

Morphological variation. males BL: 13 – 15 mmı PW: 7 – 8. Females BL: 15 mmı PW: 8 mm. Distinguished from males as follows: Head: fronto-clypeal surface striated. Few coarse puncture present posterior to cephalic carina near both eyes. Cephalic carina transversalı forming a weak pair of tubercles. Pronotum: simply convexı lacking lobes. Deeply impressed coarse punctures near anterior angles. Elytra: striae weakly impressedı punctures separated by one to twice their diameter. Interstriae convexı disc microsculpture chagrinated. Blue sheen present near basis. Abdomen: sixth ventrite three times larger than fifth and bearing a weakly central-rounded lobe.

Distribution. Peruvian and Bolivian Yungas ( Figure 34 View Figure 34 ).

Etymology. named after Patrick Arnaudı entomologist from France and who collected the holotype.