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. 

Messiphoca mauretanica nov. gen., nov. sp. représente le premier Phocidae fossile recensé en Afrique du Nord. Provenant du gisement sahélien (Miocène supérieur) de Raz-el-Aïn (Algérie), il est connu par quelques os du membre antérieur (humérus, radius, ulna), quelques vertèbres dorsales et un crâne très fragmentaire. La description de cette forme nouvelle amène à considérer Messiphoca mauretanica comme un Monachinae archaïque proche de l'origine du groupe Pliophoca - Monachus. L'incidence de cette interprétation d'un Phocidae «pré-Messinien ›› sur la crise de salinité du Messinien est aussi envisagée. 

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 rodents from the spanish locality of Can Ponsic 1 bring new data about some rodents species of the beginning of the Upper Miocene in South-West Europe. The criticims made by Mein and Freudenthal about the validity of the species Hispanomys thaleri from Can Llobateres are not justiíied. The study of the anatomy of the skull of Rotundomys from Can Ponsic 1 gives accurate information about the affinity of this genus with Cricetulus, and shows that the hypothesis, according to which Rotundomys is an ancestral form of the Arvicolids, is unlikely. The systematics of Heteroxerus and the phylogeny of the mio-pliocene Muscardinus species are also discussed. The Can Ponsic 1 locality is a little older than Can Llobateres.

  

Two species lineages of North American late Paleocene Plesiadapis exhibit a pattern of size divergence from a common ancestral lineage. Time series of fossils in each of these lineages are analyzed to test the idea that size divergence represents competitive character displacement. The critical factor in a test of character divergence is showing that divergent lineages evolved directionally rather than randomly (multifactorially). Analysis of evolutionary rates and their temporal scaling in Plesiadapis shows that both divergent species lineages have the scaling slope expected for lineages evolving randomly rather than directionally, and size divergence in Plesíadapis does not represent character displacement. Rates of evolution commonly observed on a per-generation time scale are high enough to produce character displacement within a few generations. Thus character displacement is not likely to be visible on scales of time that can be studied in the fossil record. 

A general view is given of the vertebrate faunas, Cretaceous to Quaternary of age, found in Columbia and of their principal characteristics. This view leads to the discussion of the isolation of the South American continent and of the role played by the Bolivar syncline with respect to North American immigrants during the Oligocene. The absence of marine deposits of Oligocene age in the north and northwest of Columbia suggests the possibility of a communication with Central America. This communication would have permitted the passage of hystricomorph rodents, of platyrrhine monkeys, and of colubrids. The non-occupation, until then, of the ecologie niches of these groups would have favored their installation beside the indigenous fauna. In this hypothesis it would no longer be necessary to admit that these vertebrates arrived as «island hoppers ››. The eco-biologic conditions would explain the absence of large-sized forms of North American origin. 

 Detailed anatomical description of arsinoithere cranial remains from the Lower Oligocene, Fayum Depression, Egypt, provides the basic data for a systematic investigation. All cranial and some postcranial features are assessed from a phylogenetic standpoint. Several soft tissue characters are then added to a cladistic analysis based on 54 derived ungulate morphological characters. The resulting phylogenetic hypothesis implies that perissodactyls, sirenians, proboscideans and arsinoitheres constitute a monophyletic unit (5 synapomorphies). However, increasing the tree length by 3 steps reveals a closer association between hyraxes and perissodactyls. Nevertheless, 13 synapomorphies link proboscideans, sirenians and  arsinoitheres to the exclusion of all other ungulates. Form of the sphenopalatine and ethmoid foramina, recurved posttympanic process, absence of a fenestra rotundum in the petrosal, vestigial paroccipital process of the exoccipital and the highly unusual absence of a hypoglossal foramen in the skull, imply a robust sister-group relationship between arsinoitheres and proboscideans. In this analysis artiodactyls share only one derived character with all other ungulates studied. Monophyly of Ungulata, including Artiodactyla, is therefore only weakly supported. It is argued that pedal anatomy of hyraxes is non-homologous with that of Tethytheria. Arsinoitherium should now be classified within Tethytheria, sharing a sister-group relationship with Proboscidea. Hyraxes are excluded, thus refuting the concept of Paenungulata. However, monophyly of the wider concept, Pantomesaxonia, containing hyraxes, perissodactyls, sirenians, proboscideans and now, arsinoitheres, is supported by this study. 

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. 

Les Pistes de Vertébrés du Stormberg Supérieur ("Trias terminal à Rhétien"), ou Quthingien

Si les zones du Stormberg inférieur se sont révélées contenir de nombreuses traces, surtout dans les faciès dits "Molteno moyen et supérieur", représentant apparemment la base du Keuper, il est frappant de voir pratiquement l'ensemble de cette grosse faune "Molteno" disparaître avec la fin de cette période, que nous avons appelée le "Maphutsengien".

Dès les premières zones du Stormberg supérieur, que nous nommons le"Quthingien" la zoocénose et la phytocénose, en même temps que les données d'ensemble manifestées par l'environnement, sont modifiées. Nous ne verrons plus guère de dépôts marécageux à flore riche et variée, parfois même luxuriante. Les fougères elles-mêmes ont disparu. Elles sont remplacées par de maigres plantes, aux feuilles très souvent filiformes qui paraissent témoigner d'un climat continental. Le sol est devenu de plus en plus rouge, avec des variations latérales beaucoup plus accusées. Les fleuves amenant des galets des monts du "Grand Sud" ont tari. La faune va en subir les conséquences. Certaines des espèces se révèleront sautillantes ou coureuses, pour un grand nombre plus légères et pour la quasi-totalité d'apparence carnivore ou entomophages, les phytophages devant se contenter d'un régime ingrat,difficile ou à tout le moins irrégulier,les dépôts le montrent.

C'est dans ces conditions que s'inaugure notre Etage nouveau,quelque peu discordant sur les zones A/5, A/6 ou A/7 du Stormberg inférieur (Maphutsengien). Le Stormberg supérieur (ou Quthingien) commence avec le paléopaysage remarquable dit de Moyeni, que nous allons maintenant étudier, typologiquement, avec ses homologues du même âge. Quelques 38 types d'animaux tous nouveaux vont défiler à nos yeux lors de la zone de base de cet Etage, ou zone B/1.

L'on nous avait proposé d'intituler ce Ile Tome de la série : "La grande Dalle de Moyeni et ses homologues. Paléo-spectacles, scènes et paysages animaux au Lesotho à l'approche du Trias finissant". Nous avons préféré garder le sous-titre plus haut, peut-être plus prosaïque.

Un llle Tome est en préparation : "Les développements ultérieurs et terminaux de la faune du Gondwana".

  

The biometric and morphologie variability of the cheek teeth in the end-of-the-phylum species Lophiodon lautricense Noulet studied in this note, reposes on the observation of about 800 teeth. These were revealed to be little variable in absolute dimensions. The considerable morphologie variability in the upper premolars permitted the problem of the molarization process to be taken up. An hypothesis concerning the order of eruption of the cheek teeth is formulated based on an examination of a large number of milk dentitions. In conclusion, it is suggested that reservations be held on the value of dental characters classically used in systematics for the group under consideration. 

A sample of 231 isolated teeth of lagomorphs from the upper Miocene of Montredon (southern France), identified as the ochotonid Prolagus crusafonii DOPEZ, 1975, is studied, comparing it with other populations of the same species as well as with its closest species P. oeningensis (KÖNIG, 1825).
The maintenance dining 5 m.y. of a high morphological variability in a group of non-selected features is interpreted as an evolutionary response. This may be related with the heterogeneity and probably too with the regression of the environment. 

This paper is mainly devoted to the systematics of rodents from two middle Eocene (Bartonian) localities: Chéry-Chartreuve and Rocourt-Saint-Martin (Aisne, Eastern Paris Basin). These two localities are stratigraphically located slightly above the Auversian sands. The two faunas, which comprise 11 and 8 taxa, respectively, are very different in their composition. That of Rocourt-Saint-Martin shows strong similarities with that of the geographically very close locality of Grisolles, referred to the MP16 mammalian Reference level. The very distinct fauna of Chéry-Chartreuve includes a new species of Ailuravinae, Ailuravus nov.sp, and some teeth of the theridomyid Protadelomys, which represent archaic elements in the fauna. The most abundant species of the locality represents a new genus of primitive Theridomyidae. The presence of some teeth belonging to a new species of large Remyinae, Remys nov. sp., of Elfomys engesseri HOOKER & WEIDMANN, and a population of small dimensions referred to the genus Estellomys allow a correlation with Les Alleveys (Switzerland), with however some differences that would indicate an older age for Chéry-Chartreuve. Situated at the base of the "Marinesian" from the Bassin de Paris, this fauna is unquestionably different from those referred to the MP16 reference level and could represent an older level for which the macrofauna remains very poorly known. Conversely, the comparison of rodents from La Livinière II with those present in MP16 faunas, especially those of Robiac (Gard), shows a great similarity between both localities. This casts doubts on whether to keep this La Livinière II faunule to define the current MP15 reference level, while the biostratigraphical position of Pontils 26 (Spain), previously referred to this level, is reconsidered. Chery Chartreuse could be a good candidate for a new definition of the MP15 reference level. 

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. 

Le volume 11 du «Handbuch der Paläeoherpetologie», consacré aux «Serpellles» et redigé par Jean-Claude Rage, apporte une remarquable information sur ce groupe particulier de reptiles dont on ne pouvait guere se faire une idée très précise à partir, par exemple, des seuls chapitres des traités classiques de Paléontologie et de Zoologie. 

Two steps can be distinguished in the history of the first invasion of western and south western Europe by the arvicolines. The first step corresponds to the installation of these rodents with the immigration of Promimonys inxuliferus Kowalski, then of Mimomys stehlini Kormos and of Mimomys gracilis (Kretzoi). The second is characterized by the establishment of a geographic differentiation in the arvicoline fauna between the south of France and Spain, from where are described new species of Mimomys (Mimamys cappettai, Mimomys septimanus, Mimonys medasensis), and the rest of France, where are found only elements already known from central Europe or England (Mimomys polonicus Kowalski, Mimomys pliocaenicus F. Major, Mimomys reidi Hinton, or forms very close to the latter). This geographic differentiation, which is very certainly the consequence of the division of Europe into distinct climatic provinces, one of them being the southern province comprising at least Spain and southern France, could result from a cladogenetic evolution of Mimomys stehlini and Mimomys gracilis after their immigration. The present work is also a contribution to the search for correlations between the diverse micromammal localities of the latest Pliocene (or early Villafranchian) and of the early Quaternary of Europe. 

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. 

New Dendromus species (Rodentia, Muroídea) from Langebaanweg (Pliocene, South Africa). Stratigraphical and paleoecological consequences.

Two new species of Dendromus are described from the Langebaanweg site which precises the evolutionary trend among this genus in South Africa and gives further paleoenvironmental indications. Two evolutionary stages are described: D. darti nov. sp. shows low-crowned molars with bunodont cusps and its more closest relative would be D. melanozis from the Cape region. On the contrary, D. averyi nov. sp. is more lophodont and is better related with the modem D. melanotis. Both species are at a less evolved stage than the Dendromus sp. from Laetolil Beds at Laetoli. The Langebaanweg deposits cannot still be dated by biostratigraphy but they clearly cannot be older than the basis of Pliocene times. The association of Dendromus and Mystromys in the same levels indicates a grassland environment with woodland patches as well as probable swamps. 

La faune d'artiodactyles de Ste-Néboule, qui comprend neuf espèces, présente de nombreux
points communs avec les faunes habituellement rattachées au Ludien supérieur, telles celles de La Débruge ou de Montmartre. A l'inverse de ces localités, on ne connaît pourtant, à Ste-Néboule, ni Oxacronae, ni Anoplotheriinae. Parmi les espèces du gisement se trouve une nouvelle espèce du genre Mouillacitherium (M. schlosseri n. sp.), cette forme devant être interprétée comme le dernier représentant du rameau. Nous faisons connaître par ailleurs la presque totalité de la denture du Dacrytherium saturninii, espèce qui était à ce jour très imparfaitement documentée. Ste-Néboule est, d'autre part, la seule localité où l'on peut signaler l'association probable de deux lignées du genre Amphimeryx. Les primates sont peu diversifiés à Ste-Néboule, puisque le groupe est limité au seul genre Adapis. Les genres Microchoerus et Pseudoloris, que l'on sait pourtant être représentés dans des gisements dâge voisin (Microchoerus ornatus à San Cugat de Gavadons et Mormont-Entreroches, Pseudoloris reguanti à San Cugat de Gavadons, Pseudoloris cf. reguanti à Neustadt ; cf. Louis et Sudre 1975) sont absents dans les faunes du Quercy de cette période. 

Le Quercy est aujourd'hui un vaste plateau calcaire, parcouru par un réseau karstique actif, pro· fondément entaillé par des vallées aux falaises abruptes, comme celles du Lot ou du Célé. Sur un sol peu épais domine la forêt de chênes, accompagnés de cornouillers, érables, genévriers. La faune est pauvre, peu diverse, et les nombreux chasseurs se satisfont de gibier d'élevage ...
Il y a trente-cinq millions d'années environ, le paysage était bien différent. La période de l'Eocène supérieur, qui s'achevait, avait été chaude et humide, si l'on se réfère à la fois aux paléotempératures (calculées à partir de sédiments marins extra-européens) et aux restes fossilisés de végétaux typiquement tropicaux.
Le Causse du Quercy devait être un plateau très disséqué par la karstification, à surface lapiazée creusée de gouffres en rapide évolution interne, et couvert d'un sol assez épais. Une forêt tropicale humide, avec notamment des Myricacées et des gymnospermes, recouvrait l'ensemble du pays, à peine interrompue au niveau des rares points d'eaux situés dans les bas-fonds. Dans ce cadre vivait une faune considérablement différente de la maigre faune actuelle. Si nous pouvons l'imaginer, c'est grâce aux cadavres des animaux entraînés dans les cavités par les eaux courantes ou les prédateurs, ou bien logeant et mourant dans les milieux souterrains. Nombre de ces restes, fossilisés, sont parvenus jusqu'à nous et sont aujourd'hui l'objet d'étude. 

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).