| abstract | Nine described and two new species of Macrocheles are united by a set of characters that are interpreted as reductions from a more strongly ornamented ancestor in the glaber species group (sensu Walter & Krantz 1986). These species most strongly resemble M. scutatus (Berlese), the smallest and least sclerotized species in Filipponi & Pegazzanoʼs (1962) glaber-group, and herein are assigned to four species complexes in the scutatus subgroup. Species in the scutatus complex are distributed throughout the Old World, while those of the transmigrans, paganus, and rhodesi complexes are known only from subsaharan Africa and southeastern Asia. M. scutatus, a synanthropic species, is widely distributed (Europe, Africa, Asia, New Zealand) and uses the broadest range of phoronts of any species in the subgroup. Species in the remaining complexes usually are associated with scarab beetles of the tribe Scarabaeini, the dung rollers. Scutatus subgroup associates of Scarabaeini tend to have greatly reduced sclerotization and ornamentation, perhaps as a result of reduced competitive pressures in the isolated dung balls of their scarab hosts, or because they avoid competition through early exploitation of the dung substrate. |