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. 

This paper proposes a systematic revision of the Oligocene Mongolian Ctenodactylidae, on the basis of abundant material obtained by screen/washing operations in stratified localities of the Ulantatal area (Inner Mongolia) (UTL1, 2, 3, 4, 5, 7, 6 & 8). A Chinese-German team has collected several thousands of isolated rodent teeth, and a number of fragmentary jaws. A new genus is identified (Alashania nov. gen. tengkoliensis nov. sp.), and eight former species are reevaluated, Karakoromys decessus, Tataromys sigmodon, T. minor, T. plicidens, Yindirtemys ulantatalensis, Y. bohlini, Y. deflexus, with several synonymies. A new Yindirtemys species is described: Y. shevyrevae nov. sp. and another one close to that: Y. aff. shevyrevae nov. sp. Four new species, which are rare in the localities, remain in open nomenclature because they are not well-represented. Yindirtemys differs from the other genera by the permanence of crescentic structures, while the other genera show a general reduction of the trigonoid area (= anterior valley). We define a range of size variation for each well documented population. Although the dental morphology shows a wide range of variation, given that transitional morphologies occur in a single locality, it is possible to provide a clear definition for most species. We show that dental patterns of the different genera can be derived from the pattern of Karakoromys. As a number of Tataromyinae have been determined in several localities from China, Kazakhstan and Mongolia, usually on the basis of scarce material, or surface collections, the present study would be used to re-evaluate their attribution inasmuch as the taxa are now placed in the Oligocene stratigraphy. The diversity of sizes and forms reflects the adaptive radiation of the family during the Oligocene, within a forested environment where the vegetation was probably abundant. 

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.

  

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 new European rodent from the middle Eocene of Spain, Zamoramys extraneus n. gen., n. sp., appears to be closely related to the middle Eocene chapattimyid rodents of Indo-Pakistan. This contradicts the generally accepted paleobiogeographic hypothesis of a Tethyian barrier between Europe and Asia isolating Europe during the middle Eocene. Because of this barrier, some authors have proposed that European and Asian rodents were not closely related, their similarity being the result of morphological convergence. Here monophyly has been tested, using the parsimony criterion, based on an analysis of dental characters (including discussing of homology and the validity of some characteristics). Our results indicate a phylogenetic relationship among the Asiatic Ctenodactyloidea, Zamoramys from Spain, and the European endemic Theridomyoidea. We also conclude from our analysis that theridomyoids and European ischyromyoids are probably not closely related phylogenetically. 

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. 

This paper is about the oldest African rodents faunas, from the late Early Eocene, or early Middle Eocene, Glib Zegdou (Algeria) and Chambi (Tunisia) localities. Five species are described and figured, belonging to a new family here created, the Zegdoumyidae.

This family is compared to the Early and Middle Eocene rodents families from Asia, Europe and North America (Chapattimyidae, Yuomyidae, Gliridae, Theridomyidae, lschyromyidae and Sciuravidae), as well as to those known from the Late Eocene African locality Bir El Ater (Anomaluridae and Phiomyidae).

On the one hand, it seems clear that the African endemic Anomaluridae arise from the Zegdoumyidae. On the other hand, the lschyromyidae, or primitive Sciuravidae, may be the most reliable ancestral groups for the Zegdoumyidae. Thus, this new family can be considered as the sister group for the American Sciuravidae on the one hand, and for the European Gliridae on the other hand.

The biogeographical consequences of these phylogenetic hypotheses are discussed. A new phase of communication between Europe and North Africa is inferred, during the Early Eocene. It has been followed by a short period of endemism, allowing the adaptive radiation for the Zegdoumyidae, preceding the immigration of the Phiomyidae, during the Late Eocene, probably from Asian relatives. 

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. 

The fauna from three new rodent localities (Castelmaurou, Grépiac-carrière et Grépiac-rive gauche) from Oligo-Miocene molasses of the Toulouse area is described. The one from Colomiers is completed. 11 species belonging to 4 families (Cricetidae, Eomyidae, Gliridae, Sciuridae) are present. The Miocene localities of Grépiac-carrière and Colomiers are correlated with Balizac, La Brète, Lambert and Lespignan. Grépiac-rive gauche is just a little older than these sites. Castelmaurou is somewhat younger than La Milloque and belongs to Oligocene. 

Three new fossiliferous localities, two of karstic origin, Castelnou 3 and Font Estramar, respectively Late Upper Miocene and Lower Pliocene, and one of lacustrine origin, Thuir, Lower Pliocene, add data about the transition between Miocene and Pliocene faunas of rodents in southern France. An unexpected association of taxa was present in the late Upper Miocene, including between others, Myocricetodon, Hispanomys, Ruscinomys, Cricetus barrierei, Promimomys and a new species of Stephanomys, S. dubari nov. sp. Myocricetodon is still known in the Lower Pliocene. It is shown that the large field-mice known since the Late Upper Miocene belong to two different lineages, on one side, A. jeanteti, on the other side, A. gudrunae followed by A. gorafensis. Biochronological and biogeographical implications are discussed. 

Remarkable association of a small infraorbital foramen, similar to that in recent Heterocephalus, and of a strong muscular print on the dorsal anterior part of the zygomatic plate and on the premaxillary. Several anatomical structures to be compared with those of Heterocephalus suggest relationships with this genus. Richardus supports the ancestrality of the hystricomorph character in the bathyergids 

A peculiar new rodent, Malpaisomys insularis nov. gen., nov. sp., is described from subfossil deposits of the eastern Canary Islands. The species shows some highly specialized skull features although its molars exhibit a mixture of primitive and derived characters among which a partial stephanodonty is most notable. A comparison of the new rodent with several Miocene to Holocene Muridae shows that Malpaisomys possibly shares a common ancestor with Acomys and Uranomys. 

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 Mont-Hélène's fauna [Pyrénées-Orientales, France], includes 15 species of rodents with a new one, Occitanomys montheleni n. sp. among the 9 species of the Murids which are listed. The uncommon Cricetid, Blancomys neglectus, is well represented in the fauna. Peculiarities of the population referred to Slephanomys cf. donnezaniare discussed. The locality a fissure filling may be the oldest one of Tabianian age known in Southern France. The diversity of the Murids gives evidence of a subtropical climate and of a diversified environment which may be linked to the spreading of the coastal plain following the filling up of the Roussillon Neogene Basin. 

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. 

The genus Paraulacodus has been collected in the Ch'orora formation of Upper Miocene age, in Ethiopia. The new species, P. johanesi n. sp.. is more evolved than the previously described indian species P. indicus HINTON of the Siwalik Hills area. The morphological gap between P. johanesi and the present Thryonomys is still important. 

About the early radiation of Rodents, we have now from the early tertiary of Asia, a new fossil record, and
we can do new interpretations. First the problem of the origin of Rodents is studied : considered as a sister group of Lagomorpha, it is possible to find their ancestors between the Mixodontia. Second the new facts about the origin of modern groups of Rodents are reviewed. A general scheme of this diversification can be proposed. 

Rodents first appear in the latest Paleocene or earliest Eocene as very fragmentary specimens (Family Paramyidae) known largely from a single locality. After this sparse beginning, rodents are usually abundant in the North American record if proper recovery methods are used. Utilization of rodents for biostratigraphic purposes depends on 1/ extinction, and 2/ replacement by evolution of endemic groups and/or incursions of Old World rodents, and rarely and late by South American kinds. These incursions are separated by relatively long periods of isolation in the Paleogene, but more episodic in the Neogene. At least 10 rodent zones can be characterized by major distinctions, and these zones can be amplified into as many as 16 with little trouble. In general, rodent genera permit as refined a zonation as do genera of large mammals. Distinction at a specific level has not been attempted herein except in the Blancan and Post-Blancan. 

The wear facets of primitive rodents can be homologized with those of primitive primates and ungulates. As in primates, the jaw movement was ectental, with an increased anterior component in the lingual phase (phase ll). The buccal phase (phase I) in rodents approaches the horizontal and it tends to be reduced in importance in comparison with the lingual phase. ln more advanced rodents the efficiency of grinding is increased by the development of additional cutting edges of enamel (e.g. enlargement of hypocone, development of mesoloph and lingual sinus). The buccal phase movement becomes lined up with the lingual phase movement to form a single oblique chewing stroke,resulting in planation of the crown. As the stroke becomes more longitudinal (propalinal) the enamel edges become more transverse. In Muridae propalinal chewing evolved before the loss of cusps, facets were reorientated and additional cusps developed. 

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 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.

  

The rodent-fauna (Cricetidae and Gliridae) recently found at Castell de Barbera (Spain) is similar to those from the other locslities of the Valles - Penedes - Can Ponsic 1 and Can Llobateres - : same composition and similar evolutionary level of the different species. On the other hand this fauna is different from those of Upper Vindobonian and Vallesian localities of the Calatayud - Teruel area. Castell de Barbera has an intermediate chronological position between the localities of Anwil (Switzerland) and Can Ponsic 1. It is still not possible to validate or invalidate the initial attribution based on absence of Hipparion of Castell de Barbera to the Upper Vindobonian. 

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. 

Abstract not available 

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. 

The murid fauna of the terminal Pliocene of southwest Europe is rich in at least eight genera and ten species. With the species belonging to the genera Apodemus, Rhagapodemus, and Stephanomys not being studied here, the study of the other murids resulted for one thing in the description of three new genera and three new species: Castillomys crusafonti n. g., n. sp., Occitanomys brailloni n. g., n. sp., Anthracomys meini n. sp., Valerymys ellenbergerí (THALER) n. g., and for another thing in the recognition of a form hitherto unknown in this region, Micromys praeminutus KRETZOI. Systematic study has shown that certain species of the terminal Pliocene fauna had their ancestors in the Turolian fauna presently known in Spain. The evolutionary lineages thereby recognized have been studied more in detail and a list of the evolutionary tendencies of the dendal characters has been given. A chart of the probable phyletic relationships between the different murids of the Pliocene faunas of southwest Europe (With the genus Rhagapodemus and Apodemus dominans being excluded) is given in conclusion of this work. 

Description of four new rodents from a recently discovered locality at Montalban. Theridomys crusafonti nov. sp. is considered as the ancestry of T. Iembronicus. Theridomys varian: nov. sp. includes «Theridomys» morphotypes and «Blainvilllimys» morphotypes; it could be ancestral to B. blainvillei. Pseudoltinomys nanus nov. sp. represents a new lineage paralleling in evolution that of P. gaillardi (which is equally found at Montalban). Pseudocricetodon montalbanensis nov. gen., nov. sp. designates a lineage of very small Cricetidae accompanying Eucricetodon. With these well defined new species and six others present in the locality, Montalban appears as the best faunal reference point within the biochronologic zone of La Sauvetat.
As an annex, discussion of two rodent specimens from the classic localíty of Tárrega, close in age to that of Montalban. 

A recent campaign of excavations (1965-68) undertaken by the Laboratoire de Paléontologie of Montpellier in pockets of the Quercy phosphorites, has permitted the dating of several localities thanks to the analysis of their micromammalian fauna.
The rodents of localities belonging to the middle Oligocene (La Sauvetat zone) are the object of this study. This rodent fauna has been compared to the forms coming from three stratified localities belonging to the biochronologic zone of La Sauvetat :  Balm, Montalban and Lovagny.
The abundance of material, notably of theridomyids and cricetids, permitted a summary statistical study to be effected and gave some precise details on the variability of the species (Theridomys varians in particular). Other details were provided on certain groups, notably on the upper teeth of Scíuromys cayluxi and on the milk teeth of theridomyids. Some specimens of «Sciurus» sp. and of Plesispermophilus angustidens were collected. By this means, it has been possible to establish, for the first time, a precise upper limit to the epoch of their appearance in Europe. 

The exploitation of new early Eocene localities in the Paris Basin has resulted in the collecting of  numerous mammalian remains, among which are about 300 isolated teeth representing the rodents. They belong, for the most part, to the paramyid group. Only the latest level of the early Eocene has yielded rodents belonging to the pseudosciurid group. The paramyids, the object of this study, are represented by at least 5 genera and 10 species; they are distributed among 4 clearly dilferentiated subfamilies : Paramyinae Simpson 1945, Pseudoparamyinae Michaux 1964, Ailuraviínae n. subf., Microparamyinae Wood1962.
It results from this study that the principal types of rodents in the middle and late Eocene of Europe are clearly related to the forms described here: Plesiarctomys Bravard 1850 is related to Pseudoparamys Michaux 1964, Ailuravus Rütimeyer1891 to Meldimys n. gen., Gliravus hammeli Thaler 1966 to Microparamys nanus (Theilard1927), and some Masillamys Tobien 1954 to Microparamys russelli Michaux 1964 and to M. sp. 1. Gliravus and Masillamys are the oldest representatives of the Gliridae and the Pseudosciurídae, respectively, families which will progressively replace the Paramyidae in the course of the middle and late Eocene.
Two stages can be recognized in the history of te European Paramyidae fauna during the course of the early Eocene: the older is characterized by the Mutigny fauna, the younger by the Cuis fauna.
The Mutigny fauna appears already rather diversified and does not completely correspond, point by point, to the homologous fauna of North America. A geographic differentiation seems to have been manifested rapidly, unless the fauna established in Europe was already a little different from that which established itself in North America.