Onthophagus marginatus

Onthophagus marginatus species group*. This group is diagnosed by a pale antennal club; head frons with a strong carina; elytral intervals having a median row of tubercles each bearing a strong seta; distal edges of the elytra have contrasting pale markings (brown in O. fragosus); the pygidium has distinct setiferous umbilicate punctures; males with a brush of fused long hair at the distal end of the protibiae. Its two species live in Cuba. Although no species of this group could be included in the mtDNA analysis, this aggregation is established based on a characteristic set of morphological characters mentioned in the diagnosis. The group is composed at present by O. marginatus Laporte and O. fragosus Génier & Howden. The first species is widely distributed on the island; the second has been collected in litter on an isolated patch of moist forest (650-935 m a.s.l.) (Matthews 1966; Génier & Howden 2014). There is also a third species in the Greater Antilles living in Hispaniola, O. albicornis Palisot. Matthews (1966) is of the opinion that the species of the Greater Antilles are derived from a common ancestor. This might be so because O. albicornis shares with the two Cuban species the following characters: distal edges of the elytra have contrasting pale markings (brown in O. fragosus); the antennal clubs are white while alive, turning yellowish when dead; prominent brush of fused setae emerging from the distal end of the male foretibia. Génier and Howden (2014) indicated that the protibiae of O. fragosus lacked the apical setal brush. However, photographs provided by Andrew Smith of the male O. fragosus clearly shows the existence of this structure.