The region of Porrentruy (Swiss Jura Mountains) is known for its rich and diverse assemblage of Late Jurassic coastal marine turtles (Thalassochelydia). Dominated by the “Plesiochelyidae”, this assemblage also includes representatives of the two other thalassochelydian groups, the “Thalassemydidae” and “Eurysternidae.” In this study, we present new shell-based material from Porrentruy referable to eurysternids. One specimen represents a juvenile individual or a relatively small taxon, and is notably characterized by a well fenestrated plastron exhibiting a wider than long central plastral fontanelle. Two other specimens are much larger and possibly represent the largest eurysternids known to date. The fourth specimen is characterized by a unique plastral morphology otherwise only known in very small juveniles. This is the first time this unique plastral morphology is known to persist in an adult or subadult. The new material described herein represents at least three distinct taxa, all of them probably new. However, we refrain from naming new species based on this incomplete material in order to avoid adding confusion to an already complex taxonomical situation. This study provides new insights into the great diversity of eurysternids during the Late Jurassic. 

The revision of the Rhombodontidae from the Maastrichtian of Morocco led us to the description of a new species: Rhombodus andriesi.

The biometrical study of populations of R. binkhorsti and R. microdon, species sometimes considered as synonymous, supports the conclusion that they represent two distinct species and not young and adult specimens of a single species. The stratigraphical range of these two species confirms this
result.

The reexarnination of type-series studied by C. Ararnbourg led us to revise the generic status of Rhombodus bondoni which is now ranged, because his dental features, in the new genus Dasyrhombodus showing a less derived dentition than Rhombodus. The stratigraphical range of each species is clarified within the phosphatic series. 

Nyctereutes megamastoides (Pomel) from the Villafranchian of the Auvergne and from Saint-Vallier presents cranial and dental characters sufficiently close to those of the late Pliocene canid from Perpignan (Roussillon), described by Depéret under the specific name of Canis donnezani belonging to the same genus Nyctereutes. The extinction of the European "Nyctereutes" group seems due to the too great alimentary specialization of this canid, whereas the Asiatic lineage represented in the Villafranchian by Nyctereutes sinensis Schlosser and at present by Nyctereutes procyonider Gray was able to maintain itself probably by means of a profound change in its alimentary regime. 

Carolocoutoia ferigoloi gen. et sp. nov. is the largest of protodidelphid marsupials, known from Middle Paleocene levels at Itaboraí Formation, southeastern Brazil. It differs from other members of this family in having molars with low cusps which are basally inflated, rounded crests without cutting edges, and a thick enamel layer which is wrinkled, specially at the labial half. A comparative analysis among representatives of this family led us to recognize only three genera undoubtely assignable to it:  Protodidelphis PAULA COUTO, 1952, Robertbutleria MARSHALL, 1987, and Carolocoutoia gen. nov. Protodidelphids lack the basic derived features diagnostic of Polydolopimorphian marsupials, while most of its derived features agree with its belonging to the Didelphimorphia. Protodidelphids comprise a specialized clade of opossum-like marsupials adapted to frugivorous or frugivore-omnivorous feeding habits. They differ from other didelphimorphians in having very large, spire-like entoconids, reduced and antero-posteriorly compressed paraconids, absence of stylar cusp C and of para- and metaconules, large stylar cusps B and D which are proximate to each other, short postmetacristae, eccentric protocones, and molars that increase rapidly in size from M/ml to M/m3.
  

Perutherium altiplanerise THALER, 1967 from the Late Cretaceous of Peru has long been recognized as South America's oldest known placental mammal. Since its description Perutherium has been generally regarded as having condylarth affinity Based on our identification  of a unique notoungulate synapomorphy we recognize Perutherium as the oldest and the most generalized known member of that order. This new determination and the large taxonomic diversity (five families) of notoungulates in rocks of Paleocene age in Argentina and Brazil, favor a South American origin for this group. The occurrence of notoungulates in rocks of Late Paleocene age in Asia and North America is explained by dispersal of a notoungulate stock from South America to North America and from there to Asia. 

Le présent volume est l'aboutissement d'un projet né il y a presque cinq ans. En décembre 1991, l'un d'entre nous (MG) prenait des contacts en vue de proposer un symposium sur les mammifères fossiles, dédié à D.E. Russell, dans le programme du 4e Congrès de la European Society for Evolutionary Biology. Ce congrès, baptisé "Evolution 93", devait se tenir à Montpellier en août 1993. Son Comité d'Organisation, animé par F. Catzeflis, recherchait des organisateurs de symposiums. L'idée fut acceptée avec enthousiasme par le second d'entre nous (PDG), et le titre de notre Symposium fut précisé: " Palaeobiology and Evolution of Early Cenozoic Mammals - A Symposium in Honor of D.E. Russell". Le projet fut formellement accepté par le Comité d'Organisation en avril 1992. 

Afin d'étudier la magnétostratigraphie de la colline de Montredon, j'ai prélevé en Avril 1982, 93 carottes orientées réparties sur 29 sites. J.-P. Aguilar et I. Loridant m'ont aidé durant cette opération. Pour la stratigraphie de la coupe échantillonnée et pour le contenu faunique des deux gisements de mammifères de cette colline, voir J.-P. Aguilar & J.-Y. Crochet (1982).
[...] 

The new fauna of Collet Redon (Bouches-du-Rhône, France) is dated by three rodents: Megacricetodon aff. bavaricus, Democricetodon affinis mutilus and Peridyromys cf. hamadryas. They correlate this locality with Oggenhof and Ohningen in Bavaria (Western Germany). As the radiometric age of Ohningen is estimated between 14 and 13 M.Y., these three localities are of Serravallian age. This datation brings a complete readjusment of the stratigraphy of the section of Collet Redon formerly described by Collot and Combaluzier. The marine deposits with underly the continental formation with the mammal fauna, are Burdigalian. The angular unconformity between the marine and the continental deposits gives evidence of an episode of emersion on the margin of a sedimentary basin, with deformation and erosion. Owing to the newly discovered fauna, this geodynamical event is clearly settled within the regional geographical and chronological context. Lacustrine and continental deposits of such an age were up to now unsuspected in this area. 

Micro-CT imaging is an increasingly popular method in paleontology giving access to internal structures with a high resolution and without destroying precious specimens. However, its potential for the study of hypoplasia defects has only recently been investigated. Here, we propose a preliminary study to test whether hypoplastic defects can be detected with micro-CT (μCT) scan and we assess the costs and benefits of using this method instead of naked eye. To do so, we studied 13 fossil rhinocerotid teeth bearing hypoplasia from Béon 1 (late early Miocene, Southwestern France) as positive control and 11 teeth of the amynodontid Cadurcotherium (Oligocene, Phosphorites du Quercy, Southwestern France), for which enamel was partly or totally obscured by cement. We showed that all macroscopically-spotted defects were retrieved on 3D reconstructions and selected virtual slices. We also detected additional defects using μCT scan compared to naked eye identification. The number of defects detected using μCT was greater in the Cadurcotherium dataset (paired-sample Wilcoxon test, p-value = 0.02724) but not for our control sample (paired-sample Wilcoxon test, p-value = 0.1171). Moreover, it allowed for measuring width and depth of the defects on virtual slices (sometimes linked to stress duration and severity, respectively), which we could not do macroscopically. As μCT imaging is both expensive and time consuming while not drastically improving the results, we recommend a moderate and thoughtful use of this method for hypoplasia investigations, restricted for instance to teeth for which enamel surface is obscured (presence of cement, uncomplete preparation, or unerupted germs). 

The complex taxonomic history of the paramyid rodent genus Ailuravus is reviewed. It has been described as Hyracotherium, as a creodont carnivore and as a lemuroid primate - errors at the ordínal level that are most unusual for a rodent. The genus is a member of the poorly known subfamily Ailuravinae, probably derived from some European Early Eocene species of Paramys. Aíluravus was a large arboreal paramyid with highly rugose cheek teeth, very well developed hypocone, and a remarkably weak lower incisor. It was tropical to subtropical. Three named species are recognized, A. macrurus from the Lutetian of Messel; the genotype, A. picteti, from Egerkingen, Buchsweiler and the Geiseltal, slightly later in the Lutetian; and A. stehlinschaubi, new name, from the Bartonian of Mormont-Eclépens and Robiac. One or more unnamed species are present in the Ypresian of Cuis. The species are close to a phyletic sequence. No later representatives of the genus are known. The late Eocene to earliest Oligocene North American paramyid Mytonomys, whose relationships have been obscure, is tentatively referred to the Ailuravinae. 

Until now Aplodontidae of the European Oligocene have been documented by four species only. The phylogenetic relations remained obscure. as the distribution of only one species has been known in some detail. New material made it possible to define the stratigraphic range of two of the already existing species (Plesispermophilus angustidens, Sciurodon cadurcense) and to follow their development during the Oligocene beginning with the event of the « Grande Coupure ››. Sciurodon remained nearly without change until the end of the Middle Oligocene. Plesispermophilus angustidens split into two distinct phyletic lines, one of which (P. macrodon n. sp.) reaching considerable size, is represented till the beginning of the Upper Oligocene (Pech de Fraysse, Gaimersheim). The other line leads to Plesispermophilus ernii (basal Upper Oligocene of Burgmagerbein 1. terminal Upper Oligocene of Coderet). Besides the already known forms a new small-sized species (P. atavus n. sp.) is described, which by its primitive features closely resembles the genus Plesispermophilus. Two other small-sized species already known from the Upper Oligocene (? P. argoviensis) and Lower Miocene (? P. descedens) seem to be closely related to the new species. It cannot be decided whether they are descendents of this line or have developed independently, because of their poor fossil record.
Comparison of the evolutionary modalities in the different phylogenetic lines reveals general trends. the most striking of which is the complication of the tooth pattern by the development of additional crests. In the lower molars the cusps diminuate in size and are more and more transformed into ridges. ln addition new connection between the crests appear. in the upper molars, the « selenodont » shape of the teeth becomes more and more dominant, and in the two main evolutionary lines of Plesispermophilus the metaconulus becomes duplicated. A further evolutionary trend is the size increase of the premolars compared to the molars, which is even more pronounced in the Miocene Aplodontidae.
Phylogenetic relations between the primitive Plesispermophilus and certain « prociurines ›› of Northern America as well as between Plesispermophilus (P. angustidens) and more progressive forms of the Upper Oligocene (P. ernii, P. macrodon n. sp.) can be documented. In this light, the taxonomic distinction between Prosciurinae (bunodont) and Allomyinae (selenodont) sensu Rensberger 1976 can be shown to be artificial, because it separates forms from each other, which are evidently closely related. Consequently the separation into two subfamilies has been abolished. 

The genus Microstonyx was found only in the north eastern part of Spain : M. antiquus, referable to the
Eppelsheim type, from the pyrenean basins ; M. antiquus, more progresive, from the Vallès Basin : M. major-erymanthius group, from the Teruel-Ademuz Area and from Pieru (Penedès Basin).

  

The Montredon local fauna yielded very rare bats, represented by damaged isolated teeth. Only a few documents are available for this period of the European Neogene. ln this poor state of knowledge, the material represents three undetermined species, a supposed molossid and two vespertilionids. 

This paper is an English concentrate of various Russian publications by the senior author presenting the mammaIian taxa from the Cretaceous (Albian through Santonian) of the region termed Middle Asia by Soviet geographers. The diagnoses are the unmodified, literal translation of the original version, but are followed with short complementary remarks; most of the species are illuslrated anew with SEM photographs, others are by normal photography. The fossiliferous formations are cited and arguments for their dating are given. Finally, the main vertebrate groups accompanying mammaIs are listed and the environment and climate at the time of deposition are suggested. In conclusion, an hypothesis on the origin and high diversity of tribosphenic mammals on the Cretaceous coastal plains of southwest Asia is proposed. In appendix the taxon Khuduklestes bohlini novo gen. novo sp. is formally defined. 

Editorial for celebrating the publication of the volume 20.

La revue PALEOVERTEBRATA a été fondée en 1967 par Louis THALER, à une époque où il n'existait, au plan international, que deux périodiques uniquement consacrés aux vertébrés fossiles. Actuellement ce nombre n'est que de quatre. A l'origine la revue fut essentiellement créée pour diffuser les résultats des chercheurs du Laboratoire de Paléontologie de l'Université de Montpellier, alors en début d'expansion et plusieurs thèses et de nombreux travaux directement liés à des thèses y furent publiés ce qui n'excluait déjà pas la publication d'articles d'auteurs étrangers.
[...] 

Description, for the first time, of the skull of Ruscinomys Depéret on the basis of a nearly complete specimen, and description of a new facial part of a Megacricetodon Fahlbusch skull (material from upper Miocene, Spain). New description of the skull (facial part) of " Cricetodon" incertum Schlosser on the basis of the specimen from the Oligocene of Quercy phosphorites already published by S. Schaub.
Comparison of the skull of “ C. ” incertum with that of the asiatic genus Cricetops Matthew and Granger and that of the North-American Eumys Leidy. These three genera of similar age display very distinct characteristics; their common origin must go back to the Eocene, as Wood believed.
Comparisons of the auditory regions of Ruscínomys and of Megacricetodon where important differences are noted. Comparison of the Cricetodontines from European Miocene with contemporary Cricetines. Contrary of the opinion held by Schaub, their anatomical differences do not seem suflicient to warrant the contention that none of the Cricetines derive from a form close to one of the known Cricetodontines. 

On the Track of Ice Age Mammals justifie pleinement son titre car l'auteur, Anthony J. Sutcliffe, apporte au lecteur faits et interprétations qui l'amèneront à s'intéresser encore plus au passé récent et à l'avenir de son environnement et à la question de l'impact de l'homme sur la nature. Après les chapitres qui présentent les temps glaciaires et les divers témoignages qui nous en sont parvenus, les cinquième et sixième apportent les informations nécessaires à la compréhension des résultats que nous donnent les chercheurs: principes, moyens d'étude et limites des méthodes, difficultés de l'intégration des données dans un cadre stratigraphique, variabilité des signaux climatiques, variabilité de leur intensité selon l'endroit par rapport au centre de la glaciation, complications liées à la qualité inégale de l'enregistrement géologique, en mer et sur le continent. 

The intensive exploration of the Pliocene Hadar Formation, rich in hominid remains, led us to the discovery of several micromammals levels. ln some of them, rodents are very abundant. The stratigraphic repartition of these levels do not cover the whole fossiliferous series of the formation but takes place only in the sedimentary members from Sidi Hakoma and Denen-Dora (rancing from 3.1 - 3.2 MY to 2.8 - 2.9 MY, according to the recent geochronological data). During this gap of time, the species do not show morphological changes, what allowed us to gather, in the same taxa, forms of slighty different ages.
Two striking facts, giving a lot of indications, characterize these small rodents'faunas. First, we notice the domination of the Muridae, as well on a qualitative way (number of species) as on a quantitative one (number of individuals). Then, it appears that, until now, two genera of these murids were known only in the south-western asiatic regions. So, we can suppose continuous biotops between Africa and Indian Subcontinent before 3 MY. In this hypothesis, the hominids had already the possibility to leave their african « cradle ››. Finally, almost all studied genera are still represented at the present time. This fact, previously observed in Laetolil, Omo, Olduvai contributes to remove hope of establishing a biochronological scale based on rodents, in tropical zone. Nethertheless, that allows to try a reconstruction of the palaeoenvironnement, by using the principle of actualism.
  

The geomyoid genus Dikkomys is well represented in a sample from the Black Bear Quarry Il local fauna of Early Hemingfordian age in Bennett County, South Dakota. Isolated unworn P/4's of Dikkomys matthewi WOOD have a prominent median cristid (sagicristid) with a connection to the metaconid and the hypolophid. With wear, P/4 does not become as molariform as P/4 because of this cristid.
A large sample of the Whitneyan beteromyid Proheteromys nebraskensis WOOD contains variants of the P/4 with on incipient sagicristid in approximately 18 percent of the population. The upper dentition and lower molars of Proheteromys nebraskensis are sufficiently generalized to indicate probable ancestry to Dikkomys. 

The Tertiary of the Salla-Luribay basin consists of red beds affected by the second period of the andine compression, of Miocene ending age. The Tertiary layers are exposed at an approximate elevation of 3.500 to 4.000 meters. Two stratigraphic units can be distinguished in them: the Luribay conglomerates, in which vertical clifts result from erosion, and the Salla layers consisting mostly of consolidated clays. These clays are very fossiliferous and have furnished a rich vertebrate fauna which gave to R. Hoffstetter the possibility to establish the Oligocene age of these beds. Sediments of same age has been reported to be present in several other places of Bolivia, particularly near Lacayani, where have been collected highly hypsodont Rodents, different from those found in Salla-Luribay basin.