Two somewhat “odd” taxa of theridomyid rodents, one formerly known (Bernardia marandati Vianey-Liaud, 1991) and the other new (Idicia vidalenci gen. et sp. nov.) are discussed from a taxonomical and taphonomical perspectives. These two rodents were found at Lavergne, a late middle Eocene (MP16) “phosphatière” from the Quercy (Southwest France). The genus Bernardia, being preoccupied by a scale insect (Bernardia Ashmead, 1881), is here renamed Burgia. We benefit from this nomenclatural change to describe additional new dental specimens of this patriotheridomyine species, including a previously undescribed locus (P4). The other theridomyid from Lavergne, Idicia vidalenci gen. et sp. nov., so far documented by a mandible preserving two teeth (m2-m3) is a new taxon of peculiar occlusal morphology, and whose subfamilial affinities remain unknown. These two peculiar theridomyids recorded at Lavergne are found nowhere else, whether in coeval localities in Quercy or elsewhere in Western Europe. We discuss the possible causes of their unique presence at Lavergne.
  

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.

  

The description of new material of the Upper Eoœne of France, Southem Germany and Spain together with the restudy of the material described by Thaler (1966b) as Pairomys allows to confirm the validity of the genus Ectropomys up to know controversally discussed. As a consequence the subfamily Remyinae and Oltinomyinae can be defined precisely. The study of the dental characters shows that the Remyinae in fact belong to the Theridomyidae and represent a derived evolutionary unit within this family. The Oltinomyinae together with the Theridomyinae and Issiodoromyinae very probably form a monophyletic unit. 

A new example of parallelism in the dental pattern ofthe Theridomyidae is illustrated by the description ofa new species: Theridomys Iudensis from the standard level of Antoingt (middle Oligocene). Considering the occurence ofthis parallelism phenomenon. the use of numerous qualitative and quantitative criteria is essential to characterize the different stages ofthe different evolutive lineages. Thus, a new simple parameter is proposed (CHY = H+l/0,5 L) to estimate hypsodonty of the medium hypsodont Rodentia. 

La faune de Rongeurs d'Escamps (Lot) bien que relativement pauvre en espèces (dix) s'avère riche d'enseignement pour les Rongeurs de l'Oligocène inférieur d'Europe Occidentale. Cette periode semble caracterisée par une cladogenèse des Théridomyines. A Escamps, un nouveau genre (Patriotheridomys) est décrit ainsi qu'une nouvelle espèce de Theridomys. Avec Oltmamys platyceps, décrit ici plus complètement et désormais bien situé stratigraphiquement, les deux espèces précédentes constituent un ensemble original du Sud de la France. A la même époque, en Angleterre, Allemagne et Espagne, des espèces «régionales» de Théridomyinés se dersifient.  A côté de ces formes qui ne semblent pas franchir la «Grande Coupure» sont représentées deux lignées d'Issiodoromyinés (Elfomys sp et Pseudoltmomys cuvieri), une de Théridomyiné (T. (Blainvillimys) rotundidens) ainsi qu'un Gliridé, Gliravus priscus (que l'on différencie nettement de la deuxième lignée des Gliravus oligocènes : G.  meridionalis -> G. majori). On retrouve ces formes dans les gisements plus récents du niveau de Hoogbutsel où elles sont à peine plus évoluées. Le fait que les degrés évolutifs de ces lignées soient très proches laisse supposer que le laps de temps séparant les niveaux d'Ecamps et Hoogbutsel fut relativement court.