Emmanuel Gheerbrant

Paleocene emergence of elephant relatives and the rapid radiation of African ungulates

Elephants are the only living representatives of the Proboscidea, a formerly diverse mammalian order whose history began with the 55-million years (mys) old Phosphatherium. Reported here is the discovery from the early late Paleocene of Morocco, ca. 60 mys, of the oldest and most primitive elephant relative, Eritherium azzouzorum n.g., n.sp., which is one of the earliest known representatives of modern placental orders. This well supported stem proboscidean is extraordinarily primitive and condylarth-like. It provides the first dental evidence of a resemblance between the proboscideans and African ungulates (paenungulates) on the one hand and the louisinines and early macroscelideans on the other. Eritherium illustrates the origin of the elephant order at a previously unknown primitive stage among paenungulates and “ungulates.” The primitive morphology of Eritherium suggests a recent and rapid paenungulate radiation after the Cretaceous-Tertiary boundary, probably favoured by early endemic African paleoecosystems. At a broader scale, Eritherium provides a new old calibration point of the placental tree and supports an explosive placental radiation. The Ouled Abdoun basin, which yields the oldest known African placentals, is a key locality for elucidating phylogeny and early evolution of paenungulates and other related endemic African lineages.

Un gisement sparnacien exceptionnel à plantes, arthropodes et vertébrés (Éocène basal, MP7): Le Quesnoy (Oise, France)

A new fossil locality is reported from the argiles a lignite du Soisonnais (Early Ypresian, MP7) of the Oise region (France). After the preliminary survey of the flora and the vertebrate and arthropod faunas, we propose a reconstruction of a fluvio-lacustrine palaeoenvironment with a forest, under a warm and wet seasonal climate. This site is outstanding because of the richness, diversity and the state of preservation of the fossils. The present discovery opens a unique window on terrestrial life during the Earliest Eocene.

A radiation of arboreal basal eutherian mammals beginning in the Late Cretaceous of India

Indias Late Cretaceous fossil mammals include the only undisputed pre-Tertiary Gondwanan eutherians, such as Deccanolestes. Recent studies have suggested a relationship between Deccanolestes and African and European Paleocene adapisoriculids, which have been variably identified as stem euarchontans, stem primates, lipotyphlan insectivores, or afrosoricids. Support for a close relationship between Deccanolestes and any of these placental mammal clades would be unique in representing a confirmed Mesozoic record of a placental mammal. However, some paleogeographic reconstructions place India at its peak isolation from all other continents during the latest Cretaceous, complicating reconstructions of the biogeographic history of the placental radiation. Recent fieldwork in India has recovered dozens of better-preserved specimens of Cretaceous eutherians, including several new species. Here, we incorporate these new specimens into an extensive phylogenetic analysis that includes every clade with a previously hypothesized relationship to Deccanolestes. Our results support a robust relationship between Deccanolestes and Paleocene adapisoriculids, but do not support a close affinity between these taxa and any placental clade, demonstrating that Deccanolestes is not a Cretaceous placental mammal and reinforcing the sizeable gap between molecular and fossil divergence time estimates for the placental mammal radiation. Instead, our expanded data push Adapisoriculidae, including Deccanolestes, into a much more basal position than in earlier analyses, strengthening hypotheses that scansoriality and arboreality were prevalent early in eutherian evolution. This comprehensive phylogeny indicates that faunal exchange occurred between India, Africa, and Europe in the Late Cretaceous-Early Paleocene, and suggests a previously unrecognized ∼30 to 45 Myr “ghost lineage” for these Gondwanan eutherians.

On the early biogeographical history of the African placentals

The Paleocene Adrar Mgorn local fauna recently discovered in the Ouarzazate basin (Morocco) along with several significant Eocene North African faunas, has yielded the oldest known placental mammals of Africa. Contrary to those from the Eocene which are basically endemic, the Adrar Mgorn placentals display affinities with taxa from North‐Tethyan continents and indicate active faunal interchanges between Africa and Europe (and perhaps Asia) during the Cretaceous/Paleogene times. On biogeographical grounds, two dispersal events are suggested as a working hypothesis. The oldest one, exemplified by the presence of paleoryctid and adapisoriculid “insectivores”; in the Moroccan locality, possibly took place by the K/T boundary. The second dispersal event exemplified by the discovery of an omomyid primate and possible hyaenodontid creodonts may have been contemporaneous with the Paleocene/Eocene boundary during which a marine regression is also known.

The oldest modern therian mammal from Europe and its bearing on stem marsupial paleobiogeography

We report the discovery of mammalian tribosphenic teeth from the basal Cenomanian of southwestern France that we refer to a new primitive marsupial-like form identified as a basal taxon of Marsupialiformes, a new clade recognized here to include the crown group Marsupialia and primitive stem lineages more closely related to Marsupialia than to Deltatheroida. Arcantiodelphys marchandi gen et sp nov. shares several significant marsupial-like features (s.l.) with marsupialiform taxa known from the North American Mid-Cretaceous. Among marsupialiforms, it shows a closer resemblance to Dakotadens. This resemblance, which is plesiomorphic within “tribotherians,” makes Arcantiodelphys one of the most archaic known Marsupialiformes. Moreover, Arcantiodelphys is characterized by an original and precocious crushing specialization. Both the plesiomorphic and autapomorphic characteristics of Arcantiodelphys among Marsupialiformes might be explained by an Eastern origin from Asian stem metatherians, with some in situ European evolution. In addition, the presence of a mammal with North American affinities in western Europe during the early Late Cretaceous provides further evidence of a large Euramerican biogeographical province at this age or slightly before. Concerning the paleobiogeographical history of the first stem marsupialiforms during the Albian–Cenomanian interval, 2 possible dispersal routes from an Asian metatherian ancestry can be proposed: Asia to Europe via North America and Asia to North America via Europe. The main significance of the Archingeay-Les Nouillers mammal discovery is that it indicates that the beginning of the stem marsupialiforms history involved not only North America but also Europe, and that this early history in Europe remains virtually unknown.

Late Cretaceous non-marine vertebrates from southern France: A review of recent finds

Abstract During the last few years, systematic prospections and excavations in the non-marine Campanian andMaastrichtian of southern France, from Provence in the East to the valley of the Garonne in the West, have considerably increased our knowledge of the continental vertebrates (fishes, amphibians, turtles, squamates, crocodilians, pterosaurs, dinosaurs, birds and mammals) from that time interval. A succession of faunal assemblages, corresponding to the Early Campanian, the Late Campanian/Early Maastrichtian and the Late Maastrichtian, can now be recognised, with a marked change in the dinosaur fauna during the Maastrichtian, but no clear evidence of decline during the last million years of the Cretaceous. The biogeographical complexity of the Late Cretaceous vertebrate assemblages from southwestern Europe is underlined.

FIRST ASCERTAINED AFRICAN “CONDYLARTH” MAMMALS (PRIMITIVE UNGULATES: cf. BULBULODENTATA AND cf. PHENACODONTA) FROM THE EARLIEST YPRESIAN OF THE OULED ABDOUN BASIN, MOROCCO

Abstract We report here the discovery of the first well identified “condylarths” from Africa, from the phosphatic beds of Ouled Abdoun Basin, Morocco, of probable early Ypresian age, which have also yielded the oldest known proboscidean. Abdounodus hamdii n. gen., n. sp. and Ocepeia daouiensis, gen. et sp. nov., show closest relationships with Mioclaenidae and Phenacodonta respectively. Both taxa also have resemblances with South American primitive ungulates, especially Abdounodus which resembles kollpaniine mioclaenids in several derived features, mostly related to a similar crushing specialization. However divergent specializations in Abdounodus and kollpaniines strongly suggest their parallelisms, in accordance with their age disparity. Some features of Abdounodus appear to be even original with respect to known mioclaenids. Though Ocepeia shares peculiar derived features with phenacodontids, it is strikingly specialized in its secondarily simplified p4, indicating sister-taxa relationships within Taxeopoda (Phenacodonta, Pantomesaxonia). Moreover, Ocepeia shares a remarkable derived feature with more advanced pantomesaxonian ungulates (Perissodactyla, Hyracoidea, Tethytheria and extinct relatives): the development of an entolophid. This raises the alternative question of their sister-taxa relationships within Taxeopoda and indeed the question of an African origin of Pantomesaxonia, which is congruent with the Paenungulata hypothesis.Though still poorly documented, these new Ouled Abdoun taxa show that early Paleogene African mammal faunas might provide key-data for the problem of the origin and basal phylogeny of main pantomesaxonian ungulate lineages. These fossils show again the importance of the African scene in the early evolution of (modern) eutherians and the poor state of our knowledge there.

Early African hyaenodontid mammals and their bearing on the origin of the Creodonta

We report a new proviverrine hyaenodontid creodont mammal, Boualitomus marocanensis , n.g., n.sp., from the earliest Eocene of Morocco, and provide new comments on Tinerhodon from the late Paleocene of Morocco. Aside from the autapomorphic loss of P/1, Boualitomus is characterized by a primitive morphology (e.g. M/3 subequal to M/2, short molar trigonid, narrow talonid, metaconid comparable to paraconid) which resembles most closely the proviverrine Prototomus. Boualitomus is more primitive than Prototomus , especially in its small size and the talonid of P/4 not being fully simplified, bearing at least two accessory cusps including a bulbous protostylid. These primitive features are remarkably reminiscent of Tinerhodon. The morphological relationship of Boualitomus and Tinerhodon supports the proviverrine affinity of the latter. Significant basal hyaenodontid synapomorphies of Boualitomus and Tinerhodon are the paraconid and paracristid development in M/1–3, anterior premolar morphology and occurrence of diastemata. Boualitomus and Tinerhodon throw new light upon the question of the origin of the Creodonta. Tinerhodon further fills the structural gap between Hyaenodontidae and primitive insectivore-like eutherians, and it provides additional data for the hypothesis of a didelphodontan origin for the Creodonta. The presence of cimolestids (as the stem-group of hyaenodontids) in the late Paleocene of Morocco, and the identification of Boualitomus and Tinerhodon as the most primitive and earliest known Hyaenodontidae, support an African origin of the family and its order.

Presence of the genus Afrodon [Mammalia, Lipotyphla (?), Adapisoriculidae] in Europe; new data for the problem of trans-Tethyan relations between Africa and Europe around the K/T boundary

The species Adapisoriculus? germanicus Russell 1964 from the Late Palaeocene of Walbeck (G.D.R.) is recognized, after its revision, at Cernay (late Palaeocene of France) and referred to Afrodon Gheerbrant 1988, a genus recently described from the late Palaeocene of Morocco. The affinity between the European species and A. chleuhi, from Morocco, implies a trans-Tethyan terrestrial exchange between Africa and Europe at about the time of the deposition of the Walbeck fossiliferous sediments (corresponding to the earliest Thanetian of marine depositional areas) or well prior to it. Comparison of the two species also permits an emended diagnosis of the genus to be proposed.

Les vertébrés continentaux de l’Adrar Mgorn (Maroc, Paléocène); une dispersion de mammifères transtéthysienne aux environs de la limite mésozoïque/ cénozoïque ?

Resume— Le gisement paleocene sud-marocain de l’Adrar Mgorn recele les plus anciens Mammiferes placentaires africains, dont la plupart sont les premiers reconnus dans le domaine sud-tethysien. L’identification, parmi eux, d’« Insectivores » paleoryctides, tres proches des genres strictement nord-americains Cimolestes et Palaeoryctes (Cretace superieur et/ou Paleocene), suggere une liaison par voie continentale des domaines nord-americain et africain autour de la limite Cretace superieur/Tertiaire. Celle-ci suppose une traversee transtethysienne dont nous discutons les possibilites a la lumiere des donnees paleogeographiques.