The knowledge of the Anchilophini has been lately renewed by the discovery of a rather large amount of new material still largely unpublished. This new material offers the opportunity of a systematic revision of this tribe gathering those of European Eocene Equoidea which bear no mesostyle on upper check teeth and display a heavy trend to the molarization of premolars.

A cladistic analysis has made out two genera, Anchilophus (Paranchilophus included as a subgenus), characterized by a marked lophodonty and the transverse narrowness of the cheek teeth, a rather high hypsodonty, the frequent occurrence of "crochets" and "anticrochets" on the superior ones, and a rather weak molarization of the premolars, opposite to Metanchilophus n. gen. whose cheek teeth are more transversally elongated, less high, less lophodont, with cusps better distinct, enamel thicker and premolars more molarized on the whole.

Three species of Anchilophus are recognized, A. desmaresti, type species of the genus, A. (Paranchilophus) remyi and A. (Paranchilophus) jeanteli n. sp.

The genus Metanchilophus is more diversified with the species dumasi, radegondensis, gaudini (whose a new sub-species M. g. fontensis is defined), depereli, castrensis n. sp. and chaubeti n. sp.

The skull anatomy has been moreover described with several taxa; it brings to light (for all that one can generalize) that Anchilophini were light animals with a slender and elongated snout, a thin zygomatic arch, a rather developed encephalon with an advanced gyrencephaly.

The structure of the nasal opening together with the occurrence of epitympanic sinuses and the molarizing process of the premolars corroborate the attribution of this tribe to the family PalaeotheIiidae. 

The Oligocene deposits of the Ulantatal area in Inner Mongolia (China) contain among the richest mammalian faunas from Asia. To date, only some parts of the rodent faunas have been described. Here, we propose to review the rodent faunal lists for each site, including the description of a few new rodent specimens. We describe three additional rodent species: the Cylindrodontidae Anomoemys lohiculus, the Eomyidae Asianeomys sp., and the Dipodidae Litodonomys huangheensis. This study allows us to constrain the stratigraphic range of Anomoemys lohiculus, which ranged from the late Early Oligocene to the early Late Oligocene in this area. Asianeomys sp. and Litodonomys huangheensis are dated from the latest Oligocene. These Oligocene deposits consist now of more than 70 species of mammals if we include the fauna from Kekeamu. This latter corresponds to the basal part of the Ulantatal Formation and could be dated biochronologically from the earliest Oligocene. When compared to the faunas from the Valley of Lakes in Central Mongolia, the Ulantatal faunas present a great majority of rodents, and this difference can be partly explained by sampling and description biases regarding macro-mammals. This study also shows that variations existed between Inner and Central Mongolia, especially regarding the composition of the rodent paleocommunities. However, the assessment of their evolutionary history in this part of Asia with respect to the important climate and environment changes, require further precisions and more material than current data allow. 

The review of material recently collected in the new localities from the “Phosphorites du Quercy", and different localities from the South of France, bring new informations on the genus Eucricetodon THALER. 1966, and Pseudocricetodon  THALER,  I969 (Middle and Upper Oligocene. Western Europe). Thanks to Eucricetodon huerzeleri VIANEY-LIAUD, 1972, which were unsufficiently known until now, is proposed. During the middle Oligocene Eucricetodon atavus  MISONNE, 1957 seems to give rise to two lineages. One of them led to Eucricetodon huberi,which however exhibits a larger size and a development of progressive characters on the teeth. The other would be Eucricetodon huerzeleri well differentiated at the “Mas de Pauffié" standard level (beginning of the upper Oligocene). The ornementation of lower incisors is described, when possible. Though the fossils are not abundant, it seems that the ancestral lineage, Eucriretodon atavus, remains in  the upper Oligocene (Boningen standard level). evolving into Eucricetodon praecursor SCHAUB, 1925 (Rickenbach standard level). The characters of Eucricetodon dubius  (SCHAUB. 1925), represented by a numerous population in Pech Desse and Pech du Fraysse (Quercy). confirm that this species and Eucricetodon praecursor  belong to two different lineages. As Eucricetodon dubius shows more primitive features, this species could not originale from Eucricetodon atavus -Eucricetodon huberi. The appearance of this species at the level of Mas de Pauffié could be the result of an immigration. A new definition of Pseudocricetodon incertus (SCHLOSSER. 1884) is given. This species has been found in several localities, where it had not been identified until now. lts comparison with Pseudocricetodon moguntiacus  (BAHLO. l975), found at several localities from the standard level of Antoingt (end of middle Oligocene). shows a parallel evolution to that of Pseudocetodon incertus, which is  of larger size and with a less complicated pattern of teeth. 

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.
  

Extensive sampling of the Siwalik deposits of the Potwar Plateau of northem Pakistan and from the Zinda Pir dome of central Pakistan has produced a fossil record of Miocene ctenodactylids that can be correlated with the paleomagnetic time scale. The early Miocene Prosayimys flynni (n. gen., n. sp.) is recognized as the first ctenodactylid in the Indian subcontinent. Prosayimys is ancestral to Sayimys. From the late early Miocene to the early late Miocene, there is an anagenetic succession of three species of Sayimys: S. cf. S. intermedius, S. sivalensis, and S. chinjiensis (n. sp.). Sayimys chinjiensis gave rise to the late late Miocene S. perplexus. A second lineage is represented by Sayimys minor, S. sp. A, and S. sp. B. 

The entelodonts of the Quercy phosphorites are essentially known from isolated teeth. The skull remains attributed to Entelodon magnum by Kowalewsky in 1876 and the type left mandible of Enteladon depereti RÉPELIN, 1918 do not belong to this family. From a morphologic point of view, the teeth from Quercy are quite comparable to those from the type localities of E. magnum and E. deguilhemi. In the absence of distinctive anatomical criteria between E. magnum (small species from the level of Ronzon) and E. deguilhemi (large species from the level of Villebramar) they are referred, according to their size, to one or the other of these two species. However, some of them are intermediate in size. Their existence speaks in favor of a close relationship between E. magnum and E. deguilhemi and confers a real stratigraphic interest to these entelodonts of Western Europe. Finally, some anatomical characters (notch on the mesial border of P4, presence of a paraconid joined to the metaconid, trigonid higher than talonid) considered until now as peculiar to the North American Archaeotherium and not yet cited in its European contemporary Entelodon have been brought to light on the teeth from Quercy.

  

Until the discovery of dinosaur eggshells locality in the Oukdiksou syncline, (Middle Atlas, Morocco) in 1999 (Garcia et al. this volume) the maastrichtian reptiles faunas were unknown in North Africa. Additional material from Achlouj-2 allows us to describe five oospecies, belonging to four oofamilies. The Megaloolithidae is recorded by Megaloolithus maghrebiellsis Garcia el al. and Pseudomegaloolithus atlasi oogen. novo oospec. nov. Tipoolithus achloujensis Garcia et al. is questionably considered as a Subtiliolithidae. A relatively small Elongatoloolithidae is represented by Rodolphoolithus arioul oogen. nov. oospec. nov. A thin Prismatoolithidae is described as a new oospecies of ? Pseudogeckoolithus Vianey-Liaud & Lopez-Martinez, 1997: P. tirboulensis. The diversity of these oospecies indicates that the dinosaur fauna comprises at least five dinosaur oospecies, with perhaps one sauropod and three theropods. 

Extensive collecting in previously known and new Middle Eocene rodent localities in the Subathu Group of the Rajauri and Reasi districts, Jammu and Kashmir (northwest Himalaya, India) has yielded over 500 isolated cheek teeth, numerous incisors and cheek tooth fragments, and two mandibular fragments with M/1-M/3. An analysis of this additional material and a restudy of that reported earlier from the Metka (Rajauri) area has revealed the presence of diverse Middle Eocene ctenodactyloid rodents in India. The assemblage comprises six genera and twelve species, viz.., Bírbalomys woodi, B. ibrahimshahi, B. sondaari, Basalomys vandermeuleni, B. ijlsti, B. lavocati, Chapattimys wilsoni, C. debruijni, Gumbatomys asifi, cf. Advenimus bohlini, cf. Petrokoslovia sp. indet. 1 and cf. Petrokoslovia sp. indet. 2. Most species of this assemblage are endemic to the Indian subcontinent and are referred to the Family Chapattimyidae. However, at least three taxa, viz.., cf. Advenimus bohlini, cf. Petrokoslovia sp.indet. 1 and cf. Pezrokoslovia sp. indet. 2 show close affinities with their Central and Eastern Asiatic contemporaries and are attributed to the Family Yuomyidae. The dentitions of most of the Middle Eocene rodents from India are described here in better detail thus providing more precise characterization than was available earlier. The taxonomie status of Basalomys, formerly a subgenus of Birbalomys has been raised to that of a genus. Basalomys vandermeuleni is here designated as the type species of Basalomys in place of B. ijlsti. The rodent assemblage from the Subathu Group is specifically similar to that from the coeval Kuldana Formation of Pakistan. The absence of Birbalomys ibrahimshahi and cf. Advenimus bohlini in Pakistan is related to sampling bias. The identifications of the Early Eocene rodents from Barbara Banda, Pakistan have been reexamined and the familial assignments of some of the Early and Middle Eocene rodents from Central and Eastern Asia have been discussed and reviewed in the light of recent discovery of early rodents in Mongolia.

  

Enamel microstructure in the incisors of Old- and New World hystricognath rodents:

The incisor enamel microstructure in more than 100 genera of fossil and Recent hystricognath and sciurognath rodents was studied. A multiserial schmelzmuster is present in the Hystricognathi, the Ctenodactylidae, advanced Chapattimyidae, and in Pedetes. A redefinition of pauciserial and multiserial HSB is given that makes the two enamel types unambiguously distinguishable which apparently represent well defined evolutionary levels. In the pauciserial Schmelzmuster the IPM is thicker than in the multiserial one. In pauciserial HSB the IPM always surrounds each prism, and the crystallites of the IPM run parallel to prism direction; transition zones between HSB are lacking; the inclination of the HSB is normally very low and the prism cross sections are not flattened but somewhat irregular. The number of prisms per HSB is no good distinctive character for pauciserial and multiserial HSB, since there exists a wide overlap. The pauciserial schmelzmuster is primitive, the multiseiial derived because: 1. the pauciseiial schmelzmuster appears earlier in the fossil record in the most primitive rodents (Paramyids s.l. and Ctenodactyloids); 2. the Eocene Ctenodactyloidea show pauciserial HSB but the Oligocene and younger ones are characterized by multiserial HSB; 3. in the outgroup comparison, the Eurymylidae (Mixodontia) show pauciserial HSB; 4. biomechanically, multiserial HSB strenghten the enamel better than pauciserial HSB, since their IPM runs nearly always in an angle of 45° or more to the prisms.

In multiseríal HSB three subtypes can be distinguished which are differentiated by the IPM orientation. Primitive is a (rarely strict) parallel or acute angular, anastomozing IPM, and derived is an interrow sheet-like ("plattenartige") IPM. This evolutionary polarity is indicated by enamel evolution in the Ctenodactylidae which show an acute angular IPM in the Oligocene and a rectangular interrow sheet-like IPM since the Miocene. Among the Caviomorpha a rectangular interrow sheet-like IPM is restricted to the Octodontoidea; therefore they must be considered derived in terms of their enamel structure. The first multiserial HSB in rodent incisors appear in phiomyids or chapatrimyids from the Upper Eocene of Algeria. The IPM is acute angular and anastomozing. The worldwide next younger multiserial HSB are found in Lower Oligocene phiomyids of Fayum, Egypt There already a rectangular interrow sheet like IPM is present (in Metaphiomys) besides the acute angular anastomozing IPM.

The first Caviomorpha from the Deseadan (Oligocene-Miocene) likewise show already acute angular anastomozing IPM (e.g. Scozamys) and rectangular interrow sheet-like IPM (Platypittamys). Therefore the first Caviomorpha cannot be positioned close to a transition from pauciserial to multiserial HSB. In none of the potential caviomorph ancestors from southern North America multiserial HSB or transitional stage between pauciserial and multiserial HSB could be found. The similarities between the enamel types of the Fayum rodents and the rodents from the Deseadan of South America make a derivation of the Caviomorpha from Paleogene North African phiomorph rodents or their direct ancestors most probable. This supports at the same time a descent of the platyrrhine Primates from North African anthropoids.
  

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 dentitions as well as one complete and several partial skeletons of Equoids from the Eocene lignite beds of the Geiseltal locality are revised. Instead of 13 species distinguished up to now 3 chronoclines with 5 species and 3 separate species are recognized (text. fig. 1). Propalaeotherium hassiacum HAUPT, 1925 is evolving into Propalaeotherium isselanum (CUVIER, 1824) between the levels of the « obere Unterkohle ›› and the « untere Mittelkohle ›› of the Geiseltal section. Propalaeotherium argentonicum GERVAIS, 1849 is shown to be present in the « untere Unterkohle ››, whereas Lophiotherium pygmaeum (DEPERET,1901) occurs in the « obere Mittelkohle ›› and in the « oberes Hauptmittel ››. Plagiolophus cartieri STEHLIN, 1904 appears during the transition from the « Mittelkohle ›› into the « Oberkohle ›› as the earliest true Palaeothere. Therefore the « Oberkohle ›› is already regarded as Upper Eocene. This is corroborated by the occurrence of a phyletic descendant of Propalaeatherium parvulum (Propalaeotherium n.sp.) in the middle and upper "Oberkohle " because this species appears otherwise for the first time at the mammal level of Lissieu. On the other hand Propachynolophus gaudryz (LEMOINE, 1878) described by Matthes (1977) from the « untere Unterkohle ›› turns out te be in fact a Phenacodont. Thus the decisive argument for classifying the « untere Unterkohle ›› as Lower Eocene has to be dropped. Biostratigraphically the « Unterkohle ›› and the «Basishauptrnittel ›› correspond with the lower Middle Eocene (mammal level of Messel), whereas the «unteres Hauptmittel ›› and the « untere Mittelkohle ›› are equivalent to the middle part of the middle Eocene (mammal level of lssel), and the « obere Mittelkohle ›› together with the « oberes Hauptmittel ›› coincide with the upper Middle Eocene (mammal level of Bouxwiller). 

The recent excavation of the Upper Miocene locality of Montredon (Hérault) provides a rich material of Mammals. The present study deals with rodents. The new quarry is 10 meters above the classical Depéret's Quarry. No differences have been noticed between the rodent populations coming grom these two sites. The description of two new species : Hispanomys mediterraneus and Muscardinus heintzi is given and the dormouse Eliomys is recorded there for the first time. The new zonation of the Miocene given by Aguilar (1982) and the previously established correlations between marine and continental chronological scales give Tortonien age (estimated between 9 and 10 M.Y. old) to the site of Montredon, which belongs to the Mammal zone D 2. 

Seventeen species of cricetid rodent are recognized and described from lower and middle Siwalik deposits in the Potwar Plateau of Pakistan. These species are grouped in three categories, characterized as subfamilies (e. g., Megacricetodontinae, Myocricetodontinae, and Dendromurinae); an additional and more abundant category of rodents from these deposits, the Democricetodontinae, is excluded from this study, and will be described in a later study. Fifteen of the species are new, and four new genera are described. The Siwalik cricetid taxa are : Megacricetodon aquilari, n. sp.; Megacricetodon sivalensis, n. sp.; Megacricetodon daamsi, n. sp.; Megacricetodon mythikos, n. sp.; Punjabemys downsi, n. gen. & n. sp.; Punjabemys leptos, n. gen. & n. sp.; Punjabemys mikros, n. gen. & n. sp.; Myocricetodon sivalensis, n. sp.;  Myocricetodon sp.; Dakkamyoides lavocati, n. gen. & n. sp.; Dakkamyoides perplexus, n. gen. & n. sp.; Dakkamys asiaticus, n. sp.; Dakkamys barryi, n. sp.; Dakkamys sp.; Paradakkamys chinjiensis, n. gen. & n. sp.; Potwarmus primitivus, n. gen.; and Potwarmus minimus, n. gen. & n. sp. This diverse record of middle Miocene small mammals illuminates a profound radiation of cricetid rodents in southem Asia, the effects of which were felt in Europe and Africa as well as the rest of Asia. 

The rodents (Cricetidae, Gliridae, Sciuridae) found in lacustrine, brackish marine and karstic sediments of Miocene age in Languedoc, assign the position of the different localities in the scale of "niveaux repères" used by mammalogists. Some detailed stratigraphical studies bring several correlations between this continental biochronological scale and the marine scale ; the most important results are the Aquitanian age of the "niveaux repères" of Coderet and Paulhiac, the Burdigalian age of Laugnac, Estrepouy, Vieux-Collonges, La Romieu and Sansan and the Langhian or Lower Serravallian age of La Grive M. The correlations between the Tethys and the Central Paratethys for the Lower Neogene profit also of these results, since the locality of Neudorf Spalte 1, 2 (Czechoslovakia) is shown to be younger than Sansan (France). The paleontological study has also several geological inferences for the Miocene of Languedoc ; with the calibration of this Miocene, we know quite precisely that the Lower Miocene is chiefly a time lacustrine sedimentation, and also that the marine Miocene sedimentation ends early in the Miocene Period, in Langhian or lower Serravallian times. 

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. 

The analysis of oxygene isotope variations as well as paleobotanical data suggest that the Oligocene/Miocene boundary corresponds to a transitional period marked by floristical and climatic variations. During this period, the pyreneo-alpine tectonics has contribued to modify the geography and western Europe landscapes. Faunal changes (appearances, extinctions, migrations) are observed in different mammalian groups, notably in the rodents. A study of the evolutionary trends and patterns in paleogene rodents is involved for the period ranging from level MP 28 of the Late Oligocene to the Early Miocene, including the Oligo-Miocene boundary.
The Rodents fauna from the sites of Venelles (Bouches-du-Rhône District, France) and Thezels (Lot, France), previously mentionned in litterature, have been studied. The first description of the Eomyidae of La Milloque (MP 29) has been completed. These faunas are compared to those from various localities dating from the considered period. In La Milloque, a new representative of the Eomys species is described next to a form close to Rhodanomys hugueneyae ENGESSER, 1987. It is the Eomys milloquensis nov. sp., the likely descendant of Eomys quercyi COMTE & VIANEY-LIAUD, 1987. Two new species are also described in Thezels: Eucricetodon thezelensis nov. sp., resulting from a likely and local evolution of Eucricetodon praecursor (SCHAUB, 1925) from La Milloque, which, in the same geographic area, could be at the origin of Eucricetodon hesperius ENGESSER, 1985 from Paulhiac. Plesiosminthus admyarion nov. sp., quite distinct from Plesiosminthus schaubi VIRET, 1926, which announces Plesiosminthus myarion SCHAUB 1930. Venelles 'Plesiosminthus schaubi population is considered as a sub-species, named Plesiosminthus schaubi meridionalis nov. subsp. New phylogenetic patterns are proposed. Among the Eomyidae, a quantification of various features of the M1-2/ crown (hypsodonty, degree of abrasion, occlusal angle, state of development of the I and V anticlines), and a comparison with the occlusal diagram of the other teeth among various other populations allows a more efficient separation of Eomys and Rhodanomys genera. In Western Europe, and within this period, it finally does not seem possible to gradually connect the genus Eomys to the genus Rhodanomys. The evolution of the Eomys quercyi - milloquensis lineage seems to underline a similar evolution to that which may have led from the Eomys to the Rhodanomys form. The latter which appears totally accomplished at level MP 29 of the Oligocene is considered as an immigrant. If we compare the most representative species of the Venelles, Thezels, and Coderet sites, (i.e. Rhodanomys, Eucricetodon, Adelomyarion, Peridyromys, Plesíosminthus), it becomes impossible to confirm their biochronological separation. The noticeable differences between the populations may be interpreted as geographical variations. An explanation to these variations, and to fauna's evolution during the Late Oligocene and Early Miocene can be found in the environmental modifications, supported by isotopic, paleobotanical and sedimentologic analysis. A tentative reconstruction of the environments is attempted by the cenogram method. The analysis of the fluctuations of fauna's diversity shows variations which may be correlated to a drop in temperature at MP 29, during the Late Oligocene, followed by an increase in temperature along with an aridity phenomenom, during the basal Miocene (MN O).The confrontation of various methods give the opportunity of reconstituting and comparing the evolution of the environment of three sequences of sites chosen from different regions. Ecological affinities of various rodents' species are being examined. It is possible to consider that the integration of all the conclusions resulting from this study should lead to an explanation to the evolution of rodents for the period around the Oligocene-Miocene boundary. The site of Coderet- level 3- would be posterior to the latter, at the beginnig of the Miocene, and would mark the level MN 0 of the Aquitanian.

  

The earliest cetaceans are found in the early Eocene of Indo-Pakistan. By the late middle to late Eocene, the group colonized most oceans of the planet. This late Eocene worldwide distribution clearly indicates that their dispersal took place during the middle Eocene (Lutetian). We report here the first discovery of a protocetid fossil from middle Eocene deposits of Senegal (West Africa). The Lutetian cetacean specimen from Senegal is a partial left innominate. Its overall form and proportions, particularly the well-formed lunate surface with a deep and narrow acetabular notch, and the complete absence of pachyostosis and osteosclerosis, mark it as a probable middle Eocene protocetid cetacean. Its size corresponds to the newly described Togocetus traversei from the Lutetian deposits of Togo. However, no innominate is known for the Togolese protocetid, which precludes any direct comparison between the two West African sites. The Senegalese innominate documents a new early occurrence of this marine group in West Africa and supports an early dispersal of these aquatic mammals by the middle Eocene.
  

A short review of the genera and species of snakes from the Quercy's phosphorites described by former authors is followed by the study of specimens recently collected. Most of these latter specimens belong to the Aniliidae, Boidae, Colubridae and to the Scolecophidia; the precise systematic position of some of them is not defined yet. The following genera and species are described: Eonilius europae nov. gen. and nov. sp., Platyspondylia lepta nov. gen. and nov. sp., Coluber cadurci nov. sp. and Dunnophis cadurcensis nov.  sp.; a species described by de Rochebrune (Palaeopython filholi) is revised. One of the most important conclusions of this study is that the Colubridae appear as early as the Upper Eocene. The stratigraphic repartition of these snakes shows that the rich Upper Eocene fauna is followed by the very reduced fauna of the Lower Oligocene; then the oligocene «Grande Coupure» corresponds to a very important faunistic renewal. The fauna remains poor and little diversified during the beginning of the Middle Oligocene after which there is a new faunistic explosion. 

A new artiodactyl, Diacodexis antunesi n.sp., is described from the early Eocene of Silveirinha, Portugal. Comparisons are made with Diacodexis gazini GODINOT, 1978, D. varleti SUDRE et al., 1983, D. cf. varleti from Paris Basin sites, D. sp. from Dormaal and from localities in Spain and England, D. secans from North America and D. pakistanensis from Asia; affinities and evolutive tendencies are discussed. The presence of Diacodexis in the locality of Silveirinha confirms the very early Eocene age of the latter. As Diacodexis antunesi appears ta be more primitive than D. gazini from Rians (early Eocene of France), it lends corroboration to the interpretation (essentially based previously on condylarths) of the Silveirinha assemblage as the oldest Eocene fauna known in Europe and supports the hypothesis that early artiodactyls migrated from Europe to North America. 

A detailed comparative study of a complete skeleton of Bachitherium and a cladistic analysis of the sub-order Neoselenodontia lead us to propose a cladogram and a new classification of this group. The Tylopoda are the sister-group of the Ruminantia, which are chiefly defined by the fusion of the cuboid and navicular. Within this infra-order, Amphimeryx is the sister genus of a tetraselenodont group, in which the Hypertragulidae are well-separated group from a monophyletic group defined by the loss of trapezium, fusion of capitatum and trapezoid, and the isolation of the hypoconid on lower molars. The most primitive genera of this group, Lophiomeryx and Iberomeryx still have an open trigonid on the lower molars, but this is lingually closed in Archaeomeryx, sister-genus of the higher Ruminantia which have fused metatarsals and more evolved milk teeth. We divide them into two pan/orders : Tragulina (including the recent and miocene Tragulidae, and the North-American Leptomerycidae), and Pecora, with reduced lateral metacarpals and a new crest (telocristid) on the lower premolars. Within the Pecora, the upper molars of Gelocus are more primitive than those of Bachitherium (a genus with many autapomorphies in the dentition) itself more primitive than the group Prodremotherium + Eupecora, with fused metacarpals. We consider the Eupecora (including several genera without frontal appendages) to be monophyletic.