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. 

Fourteen distinct phyletical lineages which belong at least in three families: Ischyromyidae ALSTON, 1876, Gliridae THOMAS, 1896 and Theridomyidae ALSTON, 1876, have been identified after the study of more than 3600 rodent dental remains from about twenty Early and Middle Eocene european localities. A systematical and phylogenetical revision of these rodents has been achieved. Nearly all the specific and generic diagnosis are emended. Several new combinations and synonymies are proposed. Four new species and two new genera, Euromys nov. (Ailuravinae) and Hartenbergeromys nov. (Microparamyini), are named and described. Euromys nov. gen. is known by three distinctive ypresian (MP 7 to MP 10 european reference levels) chronospecies. This new lineage is thought to be the direct ancestor of Meldimys MICHAUX, 1968 and Ailuravus RUTIMEYER, 1891. A new species of the genus Plesiarctomys BRAVARD, 1850, Pl. lapicidinarum from Condé-en-Brie (MP 8-9 reference level), allows to relate the Plesiarctomys lineage to the Pseudoparamys MICHAUX, 1964 one. The taxa Sparnacomys HARTENBERGER, 1971, Pantrogna HARTENBERGER, 1971, and Corbarimys MARANDAT, 1989 are erected to genus rank; the last one is not thought to be an Ischyromyidae. A new chronospecies of Pantrogna, P. marandati nov. sp. from the locality of Prémontré (MP 10 reference level), is described. This lineage is at the origin of two others, namely Masillamys TOBIEN, 1954, including M. mattaueri (HARTENBERGER, 1975) nov. comb. (MP 10 reference level), and Hartenbergeromys nov. gen., known from MP 10 (H. hautefeuillei nov. sp.) and MP 11 (H. parvus TOBIEN, 1954) reference levels. The phylogenetical position of Hartenbergeromys nov. gen., at the origin of the european family Theridomyidae, is discussed. The systematical and phylogenetical status of two probable Paramyinae, "Paramys" woodi MICHAUX, 1964 and an unnamed genus and species, are discussed. New populations of the primitive Gliridae Eogliravus HARTENBERGER, 1971 and of the primitive Theridomyidae Protadelomys HARTENBERGER, 1968, are described and assigned to previously known species.

  

A brief historical account of fossil vertebrate discoveries in the Eastern part of the Paris Basin between the beginning of the nineteenth century and 1950 is given. Other localities discovered since then are presented. A reconstruction of past landscapes is briefly elaborated. A biozonation based on mammals is proposed, from the Late Thanetian to the Middle Bartonian. Paleogeographical considerations are added. Suggestions regarding the search for new marnmal localities are made. 

Some new material of percrocutas from the late Miocene of Axios valley (Macedonia, Greece) is studied. They have been found in the locality of "Pentalophos 1" (PNT). The material has been described and compared with the known late Miocene percrocutas of Eurasia. This comparison indicates that it can be identified as Dinocrocuta gigantea (SCHLOSSER, 1903). A maxilla of a percrocuta, named ”Hyaena" salonicae, was found in the same area (Andrews, 1918). "Hyaena" salonicae is smaller than the PNT material. It is also compared with other material from Eurasia while its taxonomic and age problems are discussed. It belongs to Dinocrocuta and shows close relationships with D. robusta and D. senyureki; its age can be considered as late Vallesian-early Turolian. The age of the locality PNT is also discussed and a possible Vallesian age is proposed for it. 

The Laprade fauna is chronologically situated between those from Egerkingen and Lissieu and consequently, is close to the MP 14 reference-level of the European mammalian biochronological scale (Symposium of Mainz, 1987).
This new fauna is presently the oldest known in the Quercy phosphorites, formerly the Le Bretou fauna (MP 16) was considered as the oldest one. The Laprade fauna includes 21 species which belong in 7 mammalian orders (Marsupialia: Amphiperatherium bastbergense, Amphiperatherium goethei; Apatotheria: Heterohyus (Gervaisyus) pygmaeus nov. subgen., nov. sp.; Lipotyphla: Saturninia cf. mamertensis, Saturninia cf. intermedia; Chiroptera: Vespertiliavus lapradei nov. sp.; Rodentia: Protadelomys cf. lugdunensis, Elfomys nov. sp.; Primates: Nannopithex cf. filholi, cf. Pseudoloris or Pivetonia; Perissodactyla: ?Palaeotherium ?castrense, small-sized Palaeotherium sp., Plagiolophus sp., Anchilophus sp.; Artiodactyla: Dichobune cf. robertiana, Mouillacitherium cartieri, Tapirulus cf. depereti, Mixtotherium priscum, Pseudamphimeryx schlosseri, and Artiodactyla indet). Sixteen of these species are mentioned for the first time from the Quercy faunas.
The recognition of a new apatemyid, Heterohyus (Gervaisyus) pygmaeus nov. subgen., nov. sp., attests to an early origin of a lineage known in the Late Eocene. The emballonurid bat Vespertiliavus lapradei nov. sp. is presently the earliest record of this genus and family. This Auversian fauna leads to discuss the age of taxa showing archaic features. These taxa were defined on specimens collected in the Quercy during the last century and have never been found in the Quercy localities recently investigated. This fauna bears also evidence of a karstic filling episode older than those previously dated by fossils in the Quercy Jurassic.