Early Oligocene mammals from Europe are not well known. In Belgium this interval (reference level MP 21) is represented by four coeval localities, Boutersem, Boutersem-TGV, Hoogbutsel and Hoeleden. Included in a vertebrate assemblage of 20+ mammalian genera, one bat, Quinetia misonnei, has been previously described from Hoogbutsel, based on four lower dentitions. Twenty new specimens of Quinetia were recently recovered from Boutersem-TGV including six upper molars, a humerus, and thirteen lower dentitions. These new specimens confirm that Quinetia is a plecotine vespertilionid and consequently represents the earliest known occurrence of this tribe. Additionally, twenty five other dental specimens document the presence of a larger vespertilionid from Boutersem-TGV. These specimens are assigned to Myotis based on the primitive 3.1.3.3 dental formula, the presence of a single-rooted p3, myotodont lower molars, a relatively high crowned lower canine with well-developed mesial and distolingual shelves, M1 and M2 lacking both paraconules and metalophs, protofossa of M1 and M2 open posteriorly, and M3 being relatively short. The Boutersem-TGV Myotis specimens represent the earliest known record of this extant genus. Only some isolated potential myotine teeth from Le Batut (MP 19) in France are older but these teeth differ from Myotis in having upper molars with a paraloph and a protofossa closed posteriorly, both features more typical of the enigmatic “Leuconoe”. Myotodont species, such as “L”. salodorensis from Oensingen (MP 25) in Switzerland and “L”. lavocati from Le Garouillas (MP 25-28) in France, both share features of upper teeth that distinguish them from Myotis. Younger still are three Myotis species from Herrlingen 8-9 (MP 29) in Germany. Compared to the Boutersem-TGV Myotis, M. minor is much smaller with a relatively smaller, shorter and more delicate p4, M. intermedius is somewhat smaller in molar dimensions but with a substantially smaller and shorter p4, while M. major has larger m1-2, similar sized m3, smaller p4, more robust M1 and a more constricted P4 lingual shelf. The origin of Myotis appears to be at least as old as the earliest Oligocene.
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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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