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), pp. -1--1: -1

publication ID

http://doi.org/10.11646/zootaxa.4139.1.4

publication LSID

lsid:zoobank.org:pub:2744EC46-70A1-4267-AAB8-2131F5DC21DC

persistent identifier

http://treatment.plazi.org/id/03C187AE-453D-FF89-0EC8-FCF8FD55FEE7

treatment provided by

Plazi

scientific name

Dichotomius (Selenocopris) darwini
status

new species

Dichotomius (Selenocopris) darwini  new species

( Fig. 4View FIGURE 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. 4View FIGURE 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. 1View FIGURE 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 4View FIGURE 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. 1View FIGURE 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. 8View FIGURE 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).