Classification and phylogeny of the Orphninae
The name of the group was proposed (as Orphnidae) by Erichson (1847). Contemporary superspecific classification of orphnines is mostly based on the works of Renaud Paulian. He revised the genus Orphnus and divided it into 6 subgenera (Paulian, 1948), and later (Paulian, 1984) established 2 tribes, Aegidiini and Orphnini. Past researches gave higher priority to characters of sexual dimorphism, especially to processes on the head and pronotum in males. These characters vary significantly in the members of the subfamily and, generally, have low phylogenetic value in scarab beetles.
Phylogeny of the Orphninae is poorly studied and the phylogenetic relationships of some taxa within the group are unclear, as is the position of the Orphninae among the other Scarabaeidae. Preliminary computer-aided parsimony analysis was conducted for 29 terminal groups including members of majority of nominal genera and subgenera of the orphnines and 47 characters of adult morphology (Frolov 2012). The analysis yielded 20 most parsimonious trees (length 94, CI = 77, RI = 86) which have very similar topology and differs chiefly by the positions of Orphnus giganteus and O. strangulatus.
The analysis was not aimed at testing sister-group relationship of Orphninae and Allidiostomationae, therefore the characters 14, 15, 17, 37, 41, and 42 should not be considered the synapomorphies of these groups. Putative sister group relations with the Allidiostomatinae need further testing.
Erichson, W. F. 1847. Conspectus insectorum coleopterorum quae in Republica Peruana observata sunt. Archiv für Naturgeschichte, 13(1): 67-185.
Paulian, R. 1948. Revision des Orphnus Africains (Coleoptera, Scarabaeidae). Annales de la Societe entomologique de France, 117: 1-75.
Paulian, R. 1977. Les Orphnidae de Madagascar. Bulletin du Muséum National d'histoire naturelle, Paris. Ser. 3., 411: 1199-1223.
Paulian, R. 1984. Les Orphnidae Americains (Coleopteres, Scarabaeoidea). Annales de la Société Entomologique de France (N. S.), 20(1): 65-92.
Paulian, R. 1992. Un nouveau genre et une nouvelle espèce d'Orphnidae de Madagascar (Coleoptera, Scarabaeoidea). Revue Française d'Entomologie (N.S.), 14(4): 169-171.