Dichotomius (Cephagonus) socius
Creators: name: Nunes, Rafael V.
name: Vaz-de-Mello, Fernando Z.
Publisher: name: Zenodo
Year: 2020
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Scarabaeidae
Dichotomius
Dichotomius socius

description: 1.3.: Dichotomius (Cephagonus) socius (Luederwaldtı 1929) (Figure 18)
Pinotus socius Luederwaldt 1929 ı p. 127 (description)
Pinotus (Cephagonus) socius ı Luederwaldt 1930 ı p. 119
Pinotus (Cephagonus) socius ı Luederwaldt 1936 ı p. 216
Pinotus socius ı Blackwelder 1944 ı p. 208
Dichotomius (selenocopris) socius ı Vaz-de-Mello 2000 ı p. 193
Diagnosis. Dichotomius socius is distinguished from other species in the group by the following combination of characters: anterior portion of pronotum widely emarginated and covered with coarse punctures; cephalic horn carinate with rounded apexesı as large as tall; elytral striae weakly impressed and flat; female sixth ventrite emargination taking 1/third of pygidium length (contrary to D. ascanis and D. mundus in which the emargination is equivalent to one-fifth of pygidium length).
● LECTOTYPE of Pinotus socius (maleı here designated): P. socius Gillet Esp. Santo 1907 {whiteı handwritten} [MZSP];- PARALECTOTYPE of Pinotus socius (female): P. socius Gillet Esp. Santo 1907 {whiteı handwritten} [MZSP].
Non-type material. BRASIL: Bahia. Ubaíra. 13³06 ʹ 55 ” Sı 39 ³40 ʹ 03 ” W. 416 mosl. Pitfall. CMP Leite [2 ♀♀ at CEMT]; Espírito Santo: 1907 Pinotus socius Gillet [1 Ƌı 1 ♀ at CEMT]; Vargem Alta. ix-1995. JNC Louzada [1 ♀ at CEMT]; Santa Teresa. 1964 – 1967. C Elias. [4 ƋƋı 13 ♀♀ at DZUP]; Tijuco Preto. xi-1948. FJ Donor [1 ♀ at CEMT]; Minas Gerais: Berizal. Serra do Anastácio. 1375 mosl. Fezes humanas. 19-xii-2012. P Grossi [1 ♀ at CEMT]; Conceição dos Ouros. x-2002. EA Pereira [1 Ƌı 1 ♀ at CEMT]; Itamonte. 22³21 ’ Sı 44 ³48 ʹ W. 12.x-2009. T Vidaurre [1 Ƌ at CEMT]; Lavras. Poço Bonito. x-2001. P Grossi & FZ Vaz-de-Mello [2 ƋƋ at CEMT]; Nova Era. 1-iii-1995. JC Zanuncio [1 ♀ at CEMT]; São Gonçalo do Rio Abaixo. 11-x-2010. FM França [2 ƋƋı 1 ♀ at CEMT]. Viçosa. x-1981. F Fiuza [1m #ı 2 ♀♀ at CEMT]; same data but xii-1981 [1 ♀ at CEMT]; same data but x-1994. FZ Vaz-de-Mello [1 Ƌ at CEMT]; same data but Mata da Prefeitura. Luz UV. xii-1981. F Fiuza [2 ƋƋ at CEMT]; same data but x-1982 [1 ♀ at CEMT]; same data but Mata da Prefeitura. 20³48 ʹ 08 ” Sı 42 ³51 ʹ 31 ” W [2 ƋƋı 1 ♀]; same data but x-2011. J Chamorro-Rengifo [1 Ƌ at CEMT]; Paraná: Curitiba. Barigui. Xi- 1945. Ernesto [1 ♀ at DZUP]; Pato Branco. 26³11 ’ Sı 52 ³40 ʹ W. Fezes humanas. A Bugoni [1 ♀ at CEMT]; Rio de Janeiro: Cordeiro. x-1998. R Salgado [1 ♀ at CEMT]; Itatiaia. xii-1992. C Godinho [1 Ƌ at CEMT]; Nova Friburgo. xi-1993. E Grossi [1 ♀ at CEMT]; same data but xi 1997. E & P Grossi [1 ♀ at CEMT]; same data but xi- 1998 [1 Ƌ at CEMT]; same municipality but Macaé de Cima. xii-2005. E & P Grossi [1 Ƌ at CEMT]; Rio de Janeiro. Guaratiba. Iii-1956. J Guimarães [1 Ƌ at DZUP]; Rio de Janeiro. Floresta da Tijuca. x-1972. C Godinho [1 Ƌ at CEMT]; same data but xi-1972 [1 ♀ at CEMT]; same data but xii-1986 [1 ♀ at CEMT]; same locality but 15-x-2008. W Beiroz [1 Ƌ at CEMT]; São Paulo: Jundiaí. Serra do Japi. 23³14 ’ Sı 46 ³56 ʹ W. Fezes humanas. 1998. MIM Hernandéz [2 ♀♀ at CEMT].
Redescription. Colour: blackı shiny. Head: dorsal surface smooth with fine punctures. Gena borders straight. Clypeo-genal angle obtuse (110³) and with a slight protuberance. Cephalic carina with round apexı as wide as long. Coarse punctures present posteriorly to cephalic carina. Pronotum: pronotal disc delimited anteriorly by a central emargination with a pair of weak knobsı filled with coarse punctures. Anterior angles covered with fine punctures. Posterior margin with two rows of ocellate elliptical punctures. Metasternum: almost glabrousı margin of anterior lobe and sides with sparseı scattered setae. Punctures larger towards the sides of the metasternum. Elytra: striae shallowly impressed with well- defined punctures. Punctures separated by three times their diameter. Interstriae flatı semi-opaque lacking distinct microsculpture. Abdomen: sixth ventrite with strong groove all over its extension. Punctures of anterior margin of each ventrite interrupted medially. Aedeagus (Figure 15 (e-g)): basal excavation shortı only taking the central portion. Paramera having one half the length of phalobasis. Ventral portion with two well- definedı rounded excavations on each paramera.
Morphological variation. males BL: 15 – 22 mmı PW: 8 – 14 mm. Larger males (redescribed above) bear central anterior emargination on pronotum and cephalic horns are well developed. Smaller males have a simply convex pronotal disc while the cephalic horn is produced in a low cephalic carina with two acute tubercles at the apex. Both phenotypes and females have similar punctuation and setae distribution pattern. Females BL: 16 – 17 mmı PW: 9 mm. Distinguished from males as follows: Head: fronto-clypeal surface striated. Coarse punctuation presents posteriorly to cephalic carina near both eyes. Cephalic carina transversalı forming a weak pair of tubercles. Pronotum: simply convexı lacking lobes. Elytra: striae deeply impressedı punctures separated by twice their diameter. Blue sheen near basis. Abdomen: sixth ventrite with a wide “ U “ shaped emarginationı equal to 1/third of the ventrite lengthı widely emarginated (Figure 8 (e-f)).
Remarks. chosen Lectotype is the male because it has more informative characters and the diagnostic characters of this speciesı fixing its name. Luederwaldt (1929 ı 1930) commented on specimens sent to him by Staudinger in 1925 and a male and female specimens sent by Joseph Gillet in 1907ı all of which we have examined. In those publicationsı Luederwaldt stated that he had not found any diagnosis for Gillet ’ s specimens (Luederwaldt 1929) and gave a brief description and comparison of this species with D. acutircornus (Luederwaldt 1930). Indeedı despite J. Gillet having labelled these specimensı he has never published a diagnosis for D. socius. The designation of one of Gillet ’ s specimens as the lectotype fixes the species name and is based on Luederwaldt citations of 1929 and 1930.
description: Published as part of 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), pp. 2231-2351 in Journal of Natural History 53 (37) on pages 2293-2294, DOI: 10.1080/00222933.2019.1692088, http://zenodo.org/record/3665519