Hyaenodontida is a group of carnivorously adapted mammals, which was successful in the Paleogene of Africa. Contrary to Laurasian representatives, African hyaenodontidans had no ecological competitors until the late Oligocene. On one hand, the late Eocene and early Oligocene hyaenodontidans have been known since the beginning of 20th century thanks to the discovery of fossils from the Fayum area (Egypt). On the other hand, the Paleocene-Middle Eocene history of these predators was clarified only recently thanks to fieldwork in Northern Africa (Algeria, Morocco, and Tunisia). The recent discovery of the koholiine, Lahimia, in the Paleocene of Ouled Abdoun Basin (Morocco) allows the origin of the African hyaenodontidans to be traced as far back as the Selandian. A second Paleocene taxon is recorded in the Ouarzazate Basin (Morocco): Tinerhodon from the Thanetian. Lahimia and Tinerhodon interestingly display two distinct dental morphologies: Tinerhodon has very primitive dental features, while Lahimia is derived in the secant morphology of its molars and loss of P1. These differences can be explained by a presently unknown Paleocene radiation. The recent discoveries of hyaenodontidans in the late early or early middle Eocene of Gour Lazib area (Algeria) and middle Eocene-early Oligocene of Dur At-Talah (Libya) show that three new families appeared in Africa, at least during the middle Eocene: Apterodontinae, Hyainailourinae, and Teratodontinae. The postcranial material of Apterodon shows that hyaenodontidans even occupied a semi-aquatic niche in Africa. New fossils from Chambi, in Tunisia, show a common carnivorous fauna with the sites from Gour Lazib area. Interestingly, hyainailourines and teratodontines were also present in southern Africa (Sperrgebiet, Namibia; Lutetian); this is evidence that hyaenodontidans had a wide African distribution. Hyaenodontidans show a global trend of body size increase during the Paleogene. However, the recent discovery of the small hyaenodontidan Furodon in the Gour Lazib area and Chambi shows that small hyaenodontidans co-existed with large ones. Several hypotheses on hyaenodontidan origins in Africa were proposed. Some assume an endemic African origin, while others suppose several trans-Tethyan dispersals from Laurasia to Arabo-Africa. The best evidence is for the dispersal of endemic African hyainailourines and apterodontines in Europe around the Eocene-Oligocene boundary, participating in the renewal of the European carnivorous fauna at the ‘Grande Coupure’.
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Surprisingly, after the Early Cretaceous taxonomic diversity recorded in Europe, which probably is largely an artifact of inadequate taxonomy and inflation of taxa, multituberculate mammals became extremely scarce in the Late Cretaceous in this continent, being reported exclusively from the uppermost Cretaceous continental deposits of the so-called “Haţeg Island” in Transylvania, Romania. Such mammals have been documented from the Haţeg and Rusca Montană sedimentary basins, as well as from the southwestern area of the Transylvanian Basin. All these records belong to the endemic family Kogaionidae. The present paper reports additional data related to the smallest Cretaceous kogaionid, Barbatodon oardaensis Codrea, Solomon, Venczel & Smith, 2014 based on a series of new isolated teeth recovered mainly from the type locality, Oarda de Jos (Oarda A). Furthermore, the fossil locali-ties Oarda B and Vălioara are other new occurrences for the species. Based on this new material, the intraspecific variability of B. oardaensis is confirmed and its presence is attested in the three basins. Details related to the diversity of the “Haţeg Island” kogaionids are also provided.
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RBINS Staff Publications 2022 OA
