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 study of another faunal assemblage (mostly macromammals) from Torralba de Ribota (Calatayud, Zara-
goza Prov.) demonstrates the Middle "Burdigalian" age of the deposit, MEIN zone 4a. Some ten genera have been recognized. a.o. Anchitherium, Aceratherium and Lagopsis. 

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. 

The small insectivorous placental mammals from Ste-Néboule are poorly varied. Two orders of insectivores are documented : the Proteutheria by Pseudorhyncocyon cayluxi (leptictids), the Lipotyphla by Saturninia gracilis and S. beata (nyctitheriids). The bats are only rhinolophoids and mostly hipposiderids. Sufficient populations allow us to restrict the original definitions of three previous species (Hipposideros schlosseri, Palaeophyllophora quercyi, P. oltina). From now, these species can be regarded as monophyletíc. 

The description of new material from three classic middle Eocene localities of western Europe permits the addition of details to the systematics of primitive Pseudosciurids. The cranial anatomy of Protadelomys cartieri (STEHLIN and SCHAUB) from Egerkingen is described here and compared to that of the Adelomyines from the late Eocene, until now the only ones known. The morphologic and biometric study of the dentition of P. cartieri compared to that of P. alsaticus n. sp. from Bouxwiller and P. Iugdunensis n. sp. from Lissieu, forms respectively older and younger than P. cartieri, permits the evolutionary tendencies of the group to be demonstrated and shows that notable differences in age exist between these localities. This ensemble of forms can constitute a valuable guide lineage in the establishment of a fine stratigraphy of the period. Other less well known lineages are present at Egerkingen along with P. cartieri. They can be related to genera that have been noted int he late Eocene. In conclusion, a criticism of recent zonation proposals, made by divers authors, completes this article. 

In this article is described a new species of Nyctitheriidae with primitive characters: Leptacodon nascimentoi n. sp. from the early Eocene of Silveirinha (Portugal). 

The study of all the available skulls allows us to review the systematic relationships of the longirostrine Steneosaurus from the Middle Jurassic of western Europe. Up to now, Aalenian and Bajocian deposits have not yielded any significant Steneosaurus remain. In the Bathonian, the only valid longirostrine species, S. megistorhynchus, is known in the Britain-Normandy Basin, the Poitou and the Lorraine. In the Callovian, most of the longirostrine Steneosaurus remains can be attributed to the species S. leedsi. Nevertheless, some remains from the Middle Callovian of Poitou (France) show important differences with S. leedsi. A new Steneosaurus species, only known in Poitou, is created and named S. pictaviensis. The specific characters are carried by the skull (preorbital pit well marked, orbit and ptetygoid fossae shapes), by the mandible (symphysis shape) and by the teeth (ornamentation). S. megistorhynchus is probably situated near the stem of the Callovian species but remains from the Bathonian and Lower Callovian are very scarce and it is very difficult to precise the phylogenetic relationships between the longirostrine species of the Middle Jurassic.
  

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 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. 

HGL50 is a latest Early-early Middle Eocene vertebrate-bearing locality located in Western Algeria. It has produced the richest and most diverse fauna of amphibians and squamate reptiles reported from the Palaeogene of Africa. Moreover, it is one of the rare faunas including amphibians and squamates known from the period of isolation of Africa. The assemblage comprises 17 to 20 taxa (one gymnophionan, one probable caudate, three to six anurans, seven ‘lizards’, and five snakes). Two new taxa were recovered: the anuran Rocekophryne ornata gen. et sp. nov. and the snake Afrotortrix draaensis gen. et sp. nov. The locality has also yielded the first confirmed anilioid snake, the first Palaeogene gymnophionan, and probably the first caudate from the Palaeogene (and possibly from the Tertiary) of Africa. The presence of a caudate at that time in Africa would be of particular interest; unfortunately, the available material does not permit a definitive identification. The fauna comprises Gondwanan and more specifically West Gondwanan vicariants, probably autochthonous groups and a Eurasian immigrant (assuming that the identification of the caudate is accurate). The fauna from HGL50 is clearly distinguished from the few other Eocene assemblages of Africa. However, if this results largely from differences in geological ages, geographic positions of the localities and mainly differences in environments took a part in the composition of the faunas. 

Six orders of birds adapted to aquatic life are represented among the numerous avifauna of "Saint-Gérand-le-Puy": Gaviiformes, Procellariiformes, Pelecaniformes, Ciconiiformes, Phoenicopteriformes, and Anseriformes. The present study of this avifauna proposes several changes in systematics:- Procellariiformes: Puffinus arvernensis does not belong in Procellariidae but in Diomodeidae, and it is transferred to the fossil genus Plotornis previously described in the Middle Miocene of France. - Pelecaniformes: Phalacrocorax littoralis remains in Phalacrocoracidae; P. míocaenus is different from the modern species, and is transferred to the new genus Nectornis. Empheresula arvernensis, described in the Oligocene deposits of Gannat, seems to be present in Saint-Gérand-le-Puy too. Pelecanus gracilis shows many differences from the modern species, and belongs to the new genus Miopelecanus, - Ciconiiformes: Ardea formosa nom. oblit. is a synonym of Proardeola walkeri. - Anseriformes: a new species closely related to swans is described, and belongs to the fossil genus Cygnopterus, of the Middle Oligocene of Europe; this species is called C. alphonsi. The ecology of each species is suggested by comparison with that of its nearest living relatives, and by study of osteological adaptations. 

Amongst a collection of selachian teeth made at Hoegaarden in a marine level of Bruxellian (Lutetian) age, containing a reworked Landenian (Sparnacian) fauna mixed with a contemporaneous one, a few teeth of  terrestrial mammals have been discovered. They comprise two rare European taxa: ? Hallensia sp. and Palaeonictis gigantea, both known from the Landenian. Even though the ?Hallensia has not been definitely identified, il differs from the only perissodactyl of this age previously recorded from Belgium (Cymbalophus cuniculus). 

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. 

Dichobunoid artiodactyls are described in this paper from the middle Eocene Geiseltal lignite deposits near Halle (Sachsen-Anhalt, Germany). The genera Eurodexis and Parahexacodus are established based on odontologica1 studies. The type-species are E. ceciliensis (FRANZEN & KRUMBIEGEL, 1981) and P. germanicus n. sp. from the "obere Mittelkohle" (see text), MP 13. The genera are referred to the new subfamily Eurodexeinae (Dichobunidae, Artiodactyla, Mammalia), which also contains the monospecific genus Eygalayodon SUDRE & MARANDAT, 1993. These new genera show many features similar to North American homacodontids and antiacodontids. They exemplify a high degree of diversity in European dichobunids. Moreover, the family Dichobunidae includes the Dichobuninae and the Hyperdichobuninae. The connection of the posthypocristid with the postentocristid, the shift of a medial to a lingual position of the hypoconulid on the lower molars and the development of a large, caniniform P1 are regarded as the principal tendencies of the eurodexeines. The entoconid is larger and more mesially situated compared to that of Diacodexis. The hypoconulid has a lingual position on a broad postcingulid. The elongation of the premolars and the presence of diastemata are considered associated with extension of the muzzle. This and the acute tubercles of the molars could indicate a limited degree of insectivory. Protodichobune cf. oweni and Diacodexis cf. varleli, first reported here from the "untere Unterkohle" (MP 11) of the Geiseltal, demonstrate the existence of forms in the basal part of the middle Eocene, that are direct descendants of lower Eocene ones. Eurodexis russelli n. sp. from MP 10 of Premontre is the most primitive representative of Eurodexis. A further part of this lineage could be Messelobunodon sp. from MP 11 of Messel (Germany). Another form from Premontre, referred to Eurodexeinae indet., represents the origin of the lineage to Parahexacodus germanicus n. sp. from the Geiseltal (MP 13). The identification of several lineages in MP 10 is evidence of an adaptive radiation during this time. Unfortunately the history of the earlier species of Diacodexis is not known well enough to exclude earlier diversifications. Our study shows the independent development of artiodactyls at the end of the lower Eocene in Europe, North America (and maybe in Asia) with much convergence. The question of the geographic origin of the genus Diacodexis is still open. 

The present study of Artiodactyla from the Middle Eocene of the Geiseltal lignite beds concems systematics, biostratigraphy, and palaeoecology on the basis of 174 specimens: isolated remains to more complete skeletons. Instead of the formerly known five species of two families are now recognized 14 species of the Diacodexeidae, Dichobunidae, Cebochoeridae, and Haplobunodontidae. New species are Aumelasia maniai, Anthracobunodon neumarkensis, Masillabune franzeni. Four species of the Geiseltalfauna are definitely known from elswere, and five species are closely related to those from other European localities. Evidently the faunal situation of artiodactyls during the Middle Eocene of Europe was largely uniform. The distribution of artiodactyls within the sequence of the Geiseltal strata corroborates the biostratigraphical concept of the land mammal age Geiseltalian (Franzen & Haubold l986b) as well as the mammalian reference levels MP 11-13 (Franzen 1987). Reconstructions of the skulls and skeletons allow conclusions on the functional morphology and palaeoecology of the artiodactyls of the European Middle Eocene 

A classification should be both usable and useful,not too complex either in the amount of splitting or in the number of hierarchies involved, and not so simple as to give a false assurance of knowledge of relationships. Classifications are only possible because we do not have complete knowledge of the evolution of the organisms concerned because gaps in the record are necessary to allow the separation of the various taxa. Rodent classification is complicated by the large number of organisms involved and by the geat amount of parallelism that has taken place in the evolution of any and all features. If several independent features are characteristic of a certain taxon, should an effort be made to define the group on the basis of all the features, or should only one be selected as the determinant ? Unless the evolution of the several features was closely linked, the former solution will sooner or later lead to insurmountable problems. 

Le matériel provenant de nouvelles fouilles dans les phosphorites du Quercy, soumis aux divers spécialistes, a conduit à la soutenance de plusieurs thèses d'état: sur les rongeurs (Hartenberger, Vianey-Liaud), les Chiroptères et Insectivores (Sigé), les Artiodactyles (Sudre), les Squamates (Rage) et, en partie, les Chéloniens (De Broin). Chacun dans son domaine, à côté des conclusions d'ordre évolutif, paléogéographique ou paléoécologique, a pu établir des successions stratigraphiques des gisements du Quercy qui se sont révélées largement concordantes. Ainsi la succession des faunes du Quercy est actuellement l'une des mieux établies. Dans ce contexte, les différents spécialistes ont décidé de conjuguer leurs efforts dans l'étude monographique de plusieurs gisements repérés le long de cette échelle, afin de rassembler l'information paléontologique sur des faunes bien précises et de tenter d'obtenir des indications d'ordre taphonomique. 

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. 

Two new Squalicorax species, S. benguerirensis nov. sp. and S. microserratus nov. sp. are described from the Lower Maastrichtian of the Benguérir phosphate open mine, Ganntour deposit, Morocco. The species S. benguerirensis nov. sp. was classically assigned to S. yangaensis since Arambourg (1952) and has been also recognized in coeval deposits from eastern USA to Mid-East. The species S. microserratus nov. sp. correspond to the lateral teeth of S. kaupi as reported by Arambourg (1952) and which is now referred in fact to S. bassanii. The comparison of these two new species with other Anacoracids, known in Moroccan or elsewhere, allows highlighting the great taxonomic and ecological diversities of this family during the Cretaceous.
  

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".