Metallophanaeus Olsoufieff, 1924

Edmonds, W. D. & Zidek, J., 2010, A taxonomic review of the neotropical genus Coprophanaeus Olsoufieff, 1924 (Coleoptera: Scarabaeidae, Scarabaeinae), Insecta Mundi 2010 (129), pp. 1-111 : 22-23

Subgenus Metallophanaeus Olsoufieff, 1924

Metallophanaeus Olsoufieff, 1924: 23 . Type Species: Phanaeus saphirinus Sturm , original designation.

Diagnosis. General – Lower portion of eye small, width no more, and usually less, than twice that of oculogular space. Paraocular areas (genae) carinate or not lateral to eyes. Occipital areas of parietals more-or-less flattened, lacking angulate prominence (as in Fig. 12 ). Circumnotal ridge entire, not effaced behind eyes (as in Fig. 8 ). Pronotal sculpturing variable, usually granulorugose anterolaterally, punctate to some degree posteromedially; basal fossae variable. Pronotum lacking posterolateral ridge. Striae fine, simple or carinulate, anterior ends of 1-4 impressed to some degree. Hind wing not notched basally ( Fig. 10 ). Posterior surface of protibial tooth with single basal row of long setae (as in Fig. 6 ). Abdominal sterna usually smooth medially. Sexual dimorphism marked.

Male – Head bearing posteriorly curved horn. Pronotum variable, flattened or transversely concave anteromedially. Parameres variable.

Female – Protarsi absent. Pronotum variable, usually with transverse process near anterior margin.

Distribution. Eastern Brazil (east of Amazonia) southward to northeastern Argentina.

Comments. This subgenus brings together eight mostly colorful species distributed between two different species groups recognized by Edmonds (1972) and Arnaud (2002c). Only six of the eight are treated in the key and species accounts (see below). As far as we know, all Metallophanaeus species are diurnal and copronecrophagous. The subgenus as here constituted is undoubtedly paraphyletic. Affinities to Megaphanaeus (mainly via C. bellicosus , q.v.) are clearly suggested in the saphirinus group by, in particular, similarity in male secondary sexual characters (form of head and pronotum and apically hooked parameres). Affinities to the jasius group of Coprophanaeus s. st r. are equally demonstrable in the thalassinus group by male and female secondary sexual characters (male head horn and pronotal shape; swollen tips of parameres; pronotal ridge and oval concavity in female). A cogent argument can be made to isolate the two species groups of Metallophanaeus into separate subgenera. Indeed, Olsoufieff included only C. saphirinus and C. horus in this subgenus, which he defined mainly on the basis of the male pronotum; C. pertyi , C. punctatus (of which Olsoufieff had no male) and C. thalassinus he placed in Coprophanaeus s. str. We have combined the two groups here mainly because both lack (by symplesiomorphy, we presume) the notching of the hind wing (a synapomorphy) characteristic of the nominate subgenus. Our preference now is to maintain the current, probably artificial, inclusion of both groups in Metallophanaeus ; any decision otherwise should await a more formal phylogenetic analysis of the entire Coprophanaeus lineage, including Dendropaemon .

The salient differences between the two species groups recognized here reside in secondary sexual characters and in the shape of the anterior portion of the metasternum. Regarding the latter, the thalassinus group exhibits a tendency for the anterior metasternal angle (viewed in profile) to be enhanced to some degree – either squared or obviously prolonged anteriorly in contrast to the evenly curved profile seen in the saphirinus group. Accentuation of the anterior metasternal angle of the thalassinus group (supposedly most developed in C. vazdemeloi ) correlates with a tendency for the profemora to be swollen posteriorly, and for the swollen posterior surface to be divided longitudinally into a flat, glabrous area and a rounded setose area behind it. Sexual dimorphism is striking but expressed differently in the two groups. In the saphirinus group, as in Phanaeus , Sulcophanaeus and Oxysternon , the male possesses a long, gradually tapering, cylindrical head horn and prominent posteromedian pronotal salience; the female, a trituberculate cephalic carina and a convex pronotum with subtle relief and (usually) a transverse crest near the anterior margin. In the thalassinus group, the male head horn is proportionately shorter with a distinctly swollen base and the pronotum bears a transverse ridge; the female has a trituberculate cephalic carina and the pronotum bears a strong anteromedian crest followed by an oval concavity (as in many species of Coprophanaeus s. str.). Protarsi are absent in both sexes of all Metallophanaeus species.

We are not able to treat formally in this review two undoubtedly valid species belonging to the thalassinus group. One is C. vazdemeloi Arnaud (2002a) , known from the holotype male and one paratype female ( BRAZIL: Piauí – São Raimundo Nonato, Parque Nacional Serra de Capivara [Jan]) housed in the private collection of Patrick Arnaud. We have been unable to examine these specimens, which are reported to be unique among the thalassinus group for the very strong prolongation of the anteromedian angle of the metasternum. Since we have no way to reliably assess other characters of this species and to formally compare it with other members of the species group, we are obliged to exclude it from formal consideration at this time. We refer the reader to the original description and to the photographs and comments in Arnaud (2002c).

The key and species treatments below also do not consider an eighth species from the Chapada do Parecis (northern Mato Grosso, Brazil) assignable to the thalassinus group and currently under study by Fernando Vaz-de-Mello and Patrick Arnaud. It will key out below to C. thalassinus , from which it differs by the following combination of characters: new species – a) posteromedian portion of pronotum granulorugose ; b) paraocular areas flat; c) abdominal sterna distinctly punctured medially; d) elytra golden with green reflections basally and along elytral suture; pronotal disk bluish green, sides and head golden; antennal club golden; e) from Mato Grosso; f) all elytral interstriae more-or-less evenly convex; first interstria not more strongly raised than others. Coprophanaeus thalassinus differs from the new species as follows: a) posteromedian portion of pronotum with punctures grading to fine ridges to scalelike granules around basal fossae; b) posterior portion of paraocular areas convex; c) abdominal sterna smooth medially at least along midline; d) dorsum metallic green and dark blue; antennal club black; e) from Bahia; f) elytral interstriae weakly convex except first; first more strongly raised and shinier than others.

Figures

Figure 5-12. Characters of Coprophanaeus. 5) Ventral view of front left tibia of C. ensifer (arrow marks elongate tuft of setae). 6) Same, C. dardanus. 7) Left anterolateral pronotal margin of C. spitzi (arrow indicates unbroken circumnotal carina. 8) Same, C. magnoi (arrow indicates broken circumnotal carina). 9) Base of left hind wing of C. cerberus. 10) Same, C. horus. 11) Lateral view left occipital lobe of C. ensifer (asterisk marks swelling). 12) Same, C. spitzi (asterisk marks flat area).