Megaphanaeus 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 : 9-14

Subgenus Megaphanaeus Olsoufieff, 1924

Megaphanaeus Olsoufieff, 1924: 23 . Type Species: Scarabaeus lancifer Linné , original designation.

Diagnosis. General – Width of lower portion of eye about twice that of oculogular space. Paraocular areas (genae) distinctly carinate lateral to eyes. Occipital areas of parietals with angulate prominence ( Fig. 11 , asterisk). Circumnotal ridge entire, not effaced behind eyes (as in Fig. 7 ). Pronotum completely sculptured, lacking smooth areas (except C. bellicosus ); anterior surfaces transversely ridged, posterior surfaces granulorugose, becoming strongly granulate posteromedially (except C. bellicosus ); basal fossae small, punctiform. Pronotum with thick, rounded ridge ( Fig. 37 , arrow) on each side extending ventrally from base of median prominence (reaching lateral fossa in C. bellicosus , Fig. 32 , arrow). Striae ( Fig. 13- 16 ) conspicuous, always carinulate, carinulae straight or undulate. Hind wing not notched basally (as in Fig. 10 ). Posterior surface of each protibial tooth with basal, elongate, brush-like clump of densely packed, short setae ( Fig. 5 , arrow). Abdominal sterna clearly punctate along entire width; puncturing finer and sparser medially. Sexual dimorphism usually subtle, female secondary sexual features male-like.

Male – Head bearing massive, posteriorly curved horn. Pronotum deeply concave; concavity transverse, posterior (dorsal) margin developed as massive prominence of varying shape. Parameres with dorsally directed apical, sometimes attenuated processes either rounded or acute in profile.

Female – Protarsi present (except C. bonariensis ). Head bearing massive, posteriorly curved horn like that of male (except C. bellicosus ). Pronotum transversely concave; posterior (dorsal) margin of concavity developed as massive, saddle-shaped prominence usually broader than equivalent prominence in male (except C. bellicosus ).

Distribution. South America east of the Andes from the Amazon basin to northern Argentina comprising the Amazonian, Chacoan and Paranaian subregions of the Neotropical region.

Comments. Megaphanaeus is used here exactly as conceived by Olsoufieff and followed by Blackwelder (1944) and Edmonds (1972). It includes the largest known phanaeines, C. ensifer and C. lancifer , some individuals of which can exceed 50 mm in length. The other two included species, C. bellicosus and C. bonariensis , are also large but can be equaled or exceeded in size by certain Sulcophanaeus , Diabroctis Gistel and members of the jasius species group of Coprophanaeus s. str. All four species are very well known and the absence of known types for three of the four is not a barrier to consistent use of the species names. Martínez’s (1944) review of the subgenus included six species, two of which Martínez and Pereira (1967) later synonymized. Our phylogenetic view of the subgenus has the species pair C. ensifer – C. bonariensis more closely related to C. lancifer than to C. bellicosus . The latter species is a taxonomic isolate that we place in a monobasic species group in apposition to the lancifer species group. Arnaud (2002c) moved C. bellicosus to Coprophanaeus s. str. (see Comments below under C. bellicosus ).

The similar development and expression of secondary sexual features of the head and pronotum between the sexes is unique among “armed” phanaeines. The usual situation in Megaphanaeus might be called “male dominant”, because the female (except of C. bellicosus ) has acquired a decidedly masculine form: a massive head horn and broad and massive saddle-shaped pronotal prominence. Large individuals clearly differ in details of pronotal shape, but medium-sized and small individuals are virtually identical. In two species, C. lancifer and C. ensifer , the female has retained protarsi, but in C. bonariensis , which lacks protarsi in both sexes, sexing these individuals requires dissection. In contrast, the females of C. bellicosus are easily recognizable by the tridentate cephalic process and presence of protarsi. Where present, female protarsi are very susceptible to loss, leaving only a very small empty socket at the base of the tibial spur. Determining sex in this subgenus using presence or absence of female protarsi therefore requires careful examination.

The distribution of Megaphanaeus occupies much of the South American portion of the Neotropical region. The exclusive Amazonian representative is C. lancifer . Coprophanaeus bellicosus inhabits the Atlantic coastal forests (Paranaian subregion) of Brazil, while the C. ensifer – C. bonariensis pair splits the wide, xeric central swath of the continent (Chacoan subregion) from the cerrados to the Chaco thorn forests. The ranges of three of the four species (all but C. bellicosus ) converge to within very short distances in the biodiversity hotspot, Parque Nacional Noel Kempff Mercado in northeastern Bolivia; but as far as we know, no two are ecologically sympatric (collected together in the same habitat).

Besides the characters mentioned in the key, there are differences among the parameres of these species that were first pointed out by Lane and Carmargo-Andrade (1935). These are not treated in the species diagnoses below but are illustrated.

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).

Figure 35-39. Coprophanaeus lancifer. 35-36) Female habitus. 37-38) Male habitus (arrow in 37 indicates posterolateral pronotal ridge). 39) Aedeagus (lateral view on left; dorsal view on right).

Figure 29-34. Coprophanaeus bellicosus. 29-30) Female habitus. 31-33) Male habitus (arrow in 32 indicates posterolateral ridge). 34) Aedeagus (lateral view below; dorsal view above).

Figure 13-27. Characters of the Coprophanaeus subgenus Megaphanaeus. 13) Elytral surface of C. lancifer. 14) Same, C. ensifer. 15) Same, C. bonariensis. 16) Same, C. bellicosus. 17) Mesosternum and anterior portion of metasternum of C. lancifer (arrow indicates smooth area of metasternum). 18) Metasternum of C.lancifer. 19) Same, C. ensifer. 20) Dorsal view of posteromedian pronotal prominence of female C. ensifer (broad form). 21) Same (narrow form). 22) Partial lateral view of pronotum male C. ensifer (arrow indicates lateral spine). 23) Same, C. lancifer (arrow indicates vertical ridge). 24) Dorsal view of posteromedian pronotal prominence of male C. lancifer. 25) Same, female (broad form). 26) Same (narrow form). 27) Anterior view of cephalic process of female C. bellicosus.