The Oligocene Malembo locality, Cabinda exclave, Angola, has yielded a rich vertebrate fauna represented by fragmentary remains. This fossiliferous locality is the only definite occurrence of Oligocene terrestrial mammals in sub-Saharan West Africa. The hyracoids from Malembo have only been very succinctly described and compared thus far, so that their systematic attribution is not consensual among specialists. A revision now allows the identification of three (or four) medium to large-sized species represented by Geniohyus dartevellei, Pachyhyrax cf. crassidentatus, and two undetermined taxa. The species G. dartevellei is revived for the holotype of Palaeochoerus dartevellei Hooijer, 1963; this species is unique to Malembo but appears close to Geniohyus mirus, a species only known from the early Oligocene of the Fayum, Egypt. Other species of Geniohyus and Pachyhyrax crassidentatus are also only known from the early Oligocene of the Fayum. The presence of Geniohyus and Pachyhyrax cf. crassidentatus at Malembo thus supports an early Oligocene age for the fauna.
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Paleogene mammal localities of North China are particularly well represented in the Erlian Basin, Inner Mongolia. Among them, the locality of Bayan Ulan is most famous for its late Paleocene Gashatan fauna. However, the younger Arshantan fauna of the same site is not well known, since no extensive study has been done so far. Here, we present a small mammal assemblage based on dental and tarsal material from a new Arshantan collection retrieved from the red beds of the late early to early middle Eocene Arshanto Formation at Bayan Ulan. It consists of at least six different taxa: the basal lagomorph Dawsonolagus antiquus, the large pantodont Pantolambdodon sp., the tapiroid Schlosseria magister, and the rhinocerotoids Hyrachyus crista and Rhodopagus guoi nov. sp. The assemblage is dominated by perissodactyls, especially Lophialetidae and Hyracodontidae. For the first time, p4-m1 of Dawsonolagus antiquus, tarsal material from Pantolambdodon sp., and lower dentition and tarsals of Hyrachyus crista are described and illustrated. Unlike other described Arshantan faunas, the Bayan Ulan Arshantan mammal assemblage has been collected exclusively from a single locality, which contributes to the reassessment of the misunderstood Arshantan Asian Land Mammal Age.
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