Jean-Louis Hartenberger

Review and analysis of the radiation of the south American Hystricognathi (Mammalia, Rodentia)

The fossil record of the first genera of each family of South American Hystricognathi rodents is reviewed. On this basis the main events for the radiation of the infraorder on this continent are recognized. Two main events can be identified: the first occurs probably during the Eocene-Oligocene boundary, and the second at the Middle-Late Miocene boundary.

Description de la radiation des Rodentia (Mammalia) du Paléocène supérieur au Miocène; incidences phylogénétiques

Abstract Reviewing the ancestor-descendant relationships of first genera representatives of 52 fossil and extant families of rodents allow the building of a phylogenetic tree of Rodentia. The shaping of this tree suggests the distribution of these families in six suborders and six infraorders.

The Eocene Mammalian Fauna of Chambi (Tunisia) in Its Geological Context

In the Kasserine area of Tunisia there is a Cenozoic basin containing Paleogene continental deposits. Palustrine limestones located at the base of the Paleogene series have yielded the Chambi mammalian fauna. Representatives of the following mammalian orders and families have been found: Marsupialia, Peradectidae; Placentalia, Protheutheria indet.; ?Lipotyphla, ?Erinaceomorpha; Chiroptera, Rhinolophoidea, Nycterididae and Vespertilionoidea, Philisidae; Primates, Adapidae; Rodentia, Zegdoumyidae; Macroscelidea, Herodotinae; Hyracoidea, Pliohyracidae. The analysis of this local fauna provides insights into its position with regards to other North African mammalian faunas and its possible relationships with Eocene Eurasian faunas.

AN ASIAN GRANDE COUPURE

Roughly 55 million years ago the world underwent a climatic change from the warm temperatures of the Eocene to the cooler, more arid environment of the Oligocene. This Eocene/Oligocene boundary is associated with an extinction/origination event in Europe known as theGrande Coupure, whereby new immigrants from Asia replaced most of the old Eocene genera from Europe. But was such an extinction a worldwide event? One group has now looked at the fossil record from Central Asia, and has found that a similar extinction event —called the Mongolian remodelling by the authors —did indeed occur.

Nouveau mammifère insectivore (?Lipotyphla, ?Erinaceomorpha) de l’Eocène inférieur de Chambi (Tunisie)

KurzfassungEin neuer Insektenfresser,Chambilestes faussanensis n.gen., n.sp., belegt durch einen Oberkiefer mit P4/ und M1-3/, wird aus dem Unteren Eozän Tunesiens von der Fundstelle Chambi beschrieben. Er zeigt bemerkenswert archaische Merkmale, die auf eine lange endemische Evolution in Afrika zurückzuführen sind. Sie rechtfertigen die Benennung einer neuen Familie, die Chambilestidae, deren genaue systematische Stellung unsicher bleibt. Mehrere Merkmale trennen die archaischen Insektenfresser von der Gruppe der ‘Proteutheria’ und legen eine Verwandtschaft zu den Lipotyphlen nahe, besonders mit den Erinaceomorphen. Der Vergleich mitScenopagus aus dem Mittleren Eozän Nordamerikas ebenso wie mit den primitivsten Erinaceiden (Tupaiodontinen) ist besonders ergiebig. Die Detailmerkmale der Molaren sind der an der Basis gut voneinder getrennte Paracon und Metacon, das gut entwickelte Metacingulum, der in deutlich mesialer Stellung stehende Protocon (ebenso beim P4/), die große transversale Verlängerung der Kaufläche (ebenso beim P4/), die allgemein robuste Morphologie (Paracon, Metacon, Metacrista) und die starke Rückbildung des Paracon beim P4ARésuméUn nouvel insectivore,Chambilestes foussanensis n.gen., n.sp., illustré par un maxillaire portant P4/ et M1-3/, est décrit dans la localité de Chambi, de l’Eocène inférieur de Tunisie. Il présente des caractères archaïques remarquables qui sont mis au compte d’une longue évolution endémique africaine. Ceux-ci justifient l’érection d’une nouvelle famille, les Chambilestidae dont la position systématique exacte reste incertaine. Plusieurs traits l’écartent des insectivores archaïques du groupe des ‘Proteutheria’ et suggèrent une affinité avec les lipotyphlés, et en particulier avec les érinacéomorphes. La comparaison est plus particulièrement fructueuse avecScenopagus de l’Eocène moyen d’Amérique du Nord et les érinacéidés les plus primitifs (tupaiodontinés). Les caractères affines des molaires sont les paracône et métacône bien séparés à la base, le métacingulum bien développé, le protocône en position sensiblement mésial (également P4/), le grand allongement transversal du contour occlusal (également P4/), la morphologie générale robuste (paracône, métacône, métacrête) et la forte réduction du paracône sur P4/.

Un exemple de corrélation marin–continental dans le Priabonien de Roumanie. Remarques sur la Grande Coupure

Between the Calata and Turea marine series, some Priabonian continental intercalations with charophytes and mammals were found. The presence of Cricetids (Rodentia, Muroidea), one of the migrants representative of the Grande Coupure event, lead to the conclusion that in this region, like in Southern Germany, the migration of the Asian elements is earlier than in western Europe.

Observations sur la morphologie comparée des prémolaires déciduales et définitives de rongeurs fossiles

Abstract The comparative morphology of the deciduous(dP4) and successional fourth premolar (P4) is studied in successional chronospecies of the Theridomys lineage. It is shown that the allometric relation dP4/P4 has been modified through time: in more recent species the dP4 is more developed. This should suggest that juvenile stage could be longer in more recent species. Regarding the problem of the use of the juvenile dental characters in phylogenetic analysis, examples from Glirid and Ctenodactylid families are given.

What isIvanantonia efremovi (Rodentia, Mammalia)?

KurzfassungIvanantonia efremoviShevyreva 1989 aus dem frühen Eozän von Tsagan Khushu (Mongolei) wurde irrtümlich unter dem NamenOrogomys obscurusDashzeveg 1990 beschrieben. Die Form zeigt eine interessante Mischung von ursprünglichen und abgeleiteten Merkmalen: Der InzisivenSchmelz ist zweilagig und hat in der portio interna pauciseriale Hunter-Schreger-Bänder; im Unterkiefer finden sich nur drei Backenzähne; das Kronenmuster der unteren Molaren ist primitiv und ähnelt stark dem vonAlagomys, wobei jedoch das Trigonid im Vergleich zum Talonid weniger reduziert ist. Unterschiede zu anderen primitiven Nagetieren bestehen auch in der Anordnung der Usurfacetten, die auf ein Vorherrschen propalinealer Bewegungen beim Kauvorgang hindeuten. Vergleiche vonInvanantonia mit verschiedenen eozänen und oligozänen Nagern deuten mögliche Beziehungen zuNonomys aus dem Unter-Oligozän Nordamerikas an.AbstractIvanantonia efremoviShevyreva 1989, known from the Tsagan Khushu locality (Early Eocene of Mongolia), erroneously has been described asOrogomys obscurusDashzeveg 1990. This form shows an interesting association of primitive and derived characters: the enamel of the incisors is two-layered and has pauciserial Hunter-Schreger bands in portio interna; the lower tooth row has only three jugal teeth; the tooth pattern of lower molars is primitive and looks very similar to that ofAlagomys, but the trigonid is less reduced with regards to the talonid. It also differs from other primitive rodents in the distribution of wear facets, suggesting that mandibular propalineal movement was pre-eminent during chewing. Comparisons ofIvanantonia with several Eocene-Oligocene rodents indicate possible relationships to the Early Oligocene North American genusNonomys.

Louis Thaler (1930–2002)

Resume Nous presentons l’œuvre scientifique de Louis Thaler, completee d’un choix de references bibliographiques, et soulignons son influence au sein de la communaute scientifique francaise. Pour citer cet article : J.-L. Hartenberger, J. Michaux, C. R. Palevol 2 (2003) 119–124.

Évaluation des rythmes et des vitesses d'évolution chez les Mammifères

The natural selection proceeds to very different time paces according to the hierarchical level of the observations. Two methods are used by palaeontologists for reporting how fast is evolution through geological time: the taxonomical and the morphological rates of evolution. However, the interpretation and the understanding of these rates of evolution are not easy. So, there were and still are many debates, and even controversies, concerning the tempo of the history of life as depicted by fossils. Examples from European Palaeogene fossil mammals illustrate some aspects of this problem.