Dichotomius (Selenocopris) darwini, Nunes, Rafael V. & Vaz-De-Mello, Fernando Z., 2016

Nunes, Rafael V. & Vaz-De-Mello, Fernando Z., 2016, New brachypterous species of Dichotomius (Selenocopris) Burmeister (Coleoptera: Scarabaeidae: Scarabaeinae) with the definition of species groups and taxonomic notes in the subgenus, Zootaxa 4139 (1) : -

Dichotomius (Selenocopris) darwini new species

( Fig. 4 )

Material studied. Holotype: Ƌ BRASIL: Goiás: Mineiros. Parque Nacional das Emas. 18°00’51”S; 52°58’17”W. 870mosl. Prc 54. III-2011. HumFaec. MFSouza / Dichotomius darwini n. sp., holotype. RVNunes & FZVaz-de- Mello [ CEMT]. Paratypes: same as holotype [3 ♀, CEMT]; same but 17°55’47”S; 52°57’49”W. 838mosl. Prc 7. [1 ♀, CEMT]; same but 17°59’46”S; 52°56’11”W. 852mosl. Prc 37 [1 Ƌ, CEMT]; same but 18°03’43”S; 52°56’35”W. 860mosl. Prc 32 [1 Ƌ, CEMT]; same locality but 1999. G.Machado [3 Ƌ, 3♀, CEMT].

Diagnosis. In the group, D. darwini n. sp. is one of the five recognized brachypterous species and is separated from them by the wrinkling/striation on the cephalic carina ( Figs. 4 A–B, E).

Holotype. male: length: 19.5 mm. Maximum width (pronotum): 12.5 mm. Black, shinny. Head: dorsal surface wrinkled/striated. Clypeogenal junction obtuse. Margin of clypeal teeth bearing a single row of short scattered setae. Ventral clypeal process feebly bifurcated (? possibly broken). Cephalic carina striated, as tall as wide, slightly emarginated apically and lacking tubercles at apex. Clypeo-genal suture distinct. Antennal club with light red tumescence. Pronotum: wider than long and wider than elytra. Anterior excavation bearing dense coarse ocellate punctures spaced by twice their diameter. Ocellate punctures present along the pronotal margins being interrupted near the anterior angles. Pronotal disc delimited from the anterior declivity by a slight curved lobe. Anterior angles acute. Hypomeron: anterior portion with a lateral band of ocellate setose punctures. Posterior portion almost glabrous with few sparse ocellate setose punctures. Prosternum: with ocellate setose punctures: setae do not reach one quarter the length of hypomeron setae. Mesosternum: strongly narrowed, glabrous and chagrinated medially. Mesepisternum: bearing ocellate setose punctures. Posterior portion of upper margin ending in an acute angle and reaching pseudoepipleuron ( Figs. 1 B–C). Metasternum: mesometasternal suture indistinct. Anterior lobe strong narrowed medially. Ocellate setose puncture present along the anterior margin of the lobe. Long and sparse setae present along the margins of the anterior lobe. Mestasternal disc bearing a longitudinal sulcus that ends in a feeble posterior concavity. Fine puncture present around this posterior concavity, near the region between the coxae. Elytra: interstriae shinny. Lacking humeral callus. Striae punctures separated by twice their diameter. Elytral interstriae convex. Hind wings: length: 11mm. Having folding articulation. Basal sclerites glabrous. Subcostal vein intersecting costal axis at its basal quarter. Medial vein extending toward the folding articulation. Distinct setae present on the basal third of costal axis and on folding region. Part of the cubital vein present, anal vein absent. Small developed membranous portion apical to folding articulation with incomplete or weakly-marked venation. Legs: anterior tibial spur strongly bent downward at the apical third. Anterior tibiae with three well defined teeth and a fourth basal one, feebly indicated by a sinuosity. Ventral surface of anterior femur smooth, glabrous. Length of 5th hind tarsomere twice the length of the 4th hind tarsomere. Abdomen: sternites 1 to 6 glabrous and having ocellate punctures along the upper margin. Pygidium: wider than long. Shinny, glabrous, lacking distinct punctures. Paramera: (as in Figs 4 C–D) having rounded/circular excavations near the basis (dorsal view) and longitduinal excavation toward the apex (lateral and dorsal view). Apex divergent, curved outward (dorsal view). Beggining of longidutinal excavation delimited by an acute angle (lateral view).

Morphological variation. Length varies from 18.5–19.5 mm on males and from 18–21 mm on females. Pronotum width varies from 12.0– 12.5 mm on males and from 11.5–12 mm on females. Both males and females have variations in following characters: Head: height of the clypeo frontal carina varies among the individuals – generally it is direct proportional to the body size. Pronotum: anterior declivity may vary in size. In most females, the anterior declivity as well the punctures are less conspicuous. Elytra: both males and females have variations on the shining of the elytra basis, which may have brown reflections. Abdomen: Only on females, the sixth abdominal segment has a pair of central tubercles and that is typical within the brachypterous species of the quadraticeps group ( Fig. 1 A).

Distribution. Known from the municipality of Mineiros, south of the state of Goiás, Brazil. All known specimens were collected at the Parque Nacional das Emas, a major conservation unit at Central Brazil ( Fig. 8 ).

Etymology. Named after Charles Darwin (1809 – 1882), in part because of his admiration and enthusiasm on Scarabaeidae beetles and in part because this species is a good example of atrophy or disuse, a theme that that he discussed on the Chapter V of his Origin, listing several examples of brachypterous animals ( Darwin 1859).

Remarks. Due to the males pronotal and paramera conformation, it is close to the other brachypterous species in the group and to D. fissiceps (Felsche) a macropterous species occuring in gallery forests near the locality-type. D. darwini inhabits open habitat formation (a type of Cerrado grassland formation called campo-sujo). It is attracted by human feces and two individuals were seen activity during the hottest hour of the day (between 11:00 and 13:00 (M.F. Souza, personal communication).

Figures

FIGURE 1. (A) Ventral habitus of a female of Dichotomius (Selenocopris) periotoi n. sp. The white arrow at the head indicates the position of the ventral clypeal process and the white at the abdomen indicates the modification at the medial portion of the 6 th sternite; (B) lateral view of the same specimen. The white arrow indicating the position of the mesepisternum.; (C) detail of the mesepisternum of the same specimen. The white arrow indicates the posterior portion of the upper margin of the mesepisternum ending in an acute angle, which is typical of Selenocopris; (D) elytral striae and interstriae of D. (S.) fissus (Gillet); (E) elytral striae and interstriae of D. (S.) fissiceps (Felsche) (quadraticeps group); (F) head and clypeal teeth of D. (S.) bicuspis (Germar); (G) head and clypeal teeth of D. (S.) fissiceps (quadraticeps group); (H) 6 th abdominal sternite of the female of D. (S.) spadiceus (Luederwaldt); (I) 6 th abdominal sternite of the female of D. (S.) punctulatipennis (Luederwaldt) (bicuspis group); (J) 6 th abdominal sternite of the male of D. (S.) ascanius (Harold); (K) 6 th abdominal sternite of the female of D. (S.) ascanius (Luederwaldt); (L) 6 th abdominal sternite of the female of D. (S.) quadraticeps (Felsche).

FIGURE 4. Paratypes of Dichotomius (Selenocopris) darwini n. sp.: (A) male dorsal habitus; (B) female dorsal habitus; (C) dorsal view of male paramera; (D) lateral view of male paramera; (E) detail of male cephalic carina with striation; (F) detail of the anterior pronotal excavation with ocellate punctures. Scale bar = 5 mm.

FIGURE 8. Distribution of the brachypterous species of Selenocopris.