An assemblage of micromammals is reported from California Wash, a fossil bearing continental deposit in the San Pedro Valley, Arizona, late Blancan in age. Cricetid and Arvicolid rodents are richly represented, including four and two species, respectively. This study mainly focuses on Sígmodon, the most abundant form. The sample of Sigmodon is compared to samples of the same genus from other localities of the San Pedro Valley of comparable age, and some inferences on the taxonomy of the genus are attempted. The specimens are referred to Sigmodon minor and Sigmodon cf. S. curtisi. Other cricetids (Onychomys pedroensis and Baiomys brachygnathus) and arvicolids (Mictomys vetus and Ondatra ídahoensis) are also recognized and described. 

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 object of this work is the study of the artiodactyls of the karstic locality of Lissieu near Lyon. Among the sixteen species counted, five (Hyperdichobune nobilis, Hyperdichobune sp., Haplabunodon mulleri, Tapirulus depereti and Pseudamphimeryx schlosseri) are cited for the first time in this fauna. The description of part of the anterior dentition of «Dichobune» langi permits the referal of this species to the genus Hyperdichobune. The new selenodont species Dichodon lugdunensis  described in this work belongs, with its ancestor Dichodon simplex, to a lineage distinct from that of Dichodan cartieri and Dichodon ruetimeyeri. Finally, the taxonomic reality of the Lissieu species, Lophiobunodon rhodanicum Deperet, is justified. All the other species have been compared with those of Egerkingen. Even though with most of them no difference in age can be shown between the two deposits, some however indicate clearly by their degree of evolution that Lissieu is slightly more recent than Egerkingen. ln the history of Eocene mammals, the Lissieu fauna, because of its homogeneity, can be considered as a sure reference fauna of the Auversian period. 

Two new species, Omanodon minor n. g., n. sp. and Shizarodon dhofarensis n. g., n. sp., known from fifteen isolated teeth, are described here as the first adapiform primates (?Anchomomyini) recognizable to date in the Taqah material (early Oligocene of Sultanate of Oman).

Omanodon minor n. g., n. sp. displays special morphological similarity to the adapid tribe Anchomomyini from the Eocene of Europe, and especially to the Anchomomys lineage. Resemblances with the extant lemurifonn Microcebus are also noticeable and could be regarded as supporting Schwartz & Tattersall (1983) hypothesis of special relationships between the anchomomyine adapids and the cheirogaleid lemuriformes. However, these morphological affmities can be interpreted, altematively, as the results of parallelisms: important differences in upper molars indicate that the resemblances of cheirogaleids and Omanodon minor n. g., n. sp. are indeed probably due to parallelisms. Phyletic relationship of O. minor n. g., n. sp. to Anchomomyini is finally the most likely hypothesis.

Shizarodon dhofarensis n. g., n. sp., although much more poorly known, is closely related to Omanodon minor n. g., n. sp., at least at a familial level. The general morphology of this species suggests
also a close link with adapid Anchomomyini, although precise relationships within this tribe remain obscure. Interesting resemblances of Shizarodon dhofarensis n. g., n. sp. to Djebelemur martinezi lower molars (early Eocene of Tunisia) are also noticeable. These resemblances are even stronger than those betwen Omanodon minor and Djebelemur martinezi. However the very bunodont upper molars referred to D. martinezi are unusual for adapids, and there are moreover some notable differences in their lower molars. Thus resemblances in Djebelemur and Shizarodon are probably due to paralellisms.

Because of the fragmentary nature of the material and of possible parallelisms, the systematic position of Omanodon and Shizarodon within adapiformes cannot however yet be established definitively. 

A fossil fish fauna, based on 5533 otoliths, from the La Paillade locality at Montpellier is described and figured. The otolith-bearing marls correlate to mammal zone MN l (Aguilar, 1982), and thus represent the earliest Miocene. The fish fauna consists of 30 taxa belonging to 20 families. Two species are new: Dussumieria sittigi and Liza gaudanti. The predominant faunal element is the Lesueurigobius vicínalis-species complex, composing 73% of all investigated otoliths. The palaeoecological analysis reveals a marine to euryhaline fish fauna living under tropical to subtropical conditions in the transition zone littoral - sublittoral. Water depth probably was more than 10 m. The scarcity of pelagic físhes suggests that the habitat was either a sheltered bay and/or far away from the open sea. Furthermore, some genera represented in the La Paillade fish fauna presently live exclusively in the Indopacific realm. Their presence strongly supports a broad connection between the Indian Ocean, the Mediterranean, and the Paratethys Seas during the Early Miocene (Aquitanian). From a palaeobiogeographical point of view, faunal relationships were found between the La Paillade fish fauna and both the Paratethys fish fauna and the fish fauna from the deposits in the Upper Rhinegraben and the Mayence and Hanau Basins (Germany).



  

The anatomy of Norselaspis glacialis n.g., n.sp., a primitive kiaeraspidian from the Lower Devonian of Spitsbergen, is described on the basis of spécimens studied by grinding sections or prepared with dilute formic acid. This study yielded some new anatomical details, including the presence of a canal prolonging posteromedially the canal alloted to the facial nerve by Stensiö. This posterior prolongation of the « facial canal ›› into the posterolateral part of the labyrinth cavity is consistent with the hypothesis put forward by Allis, Lindström, Jefferies and Whiting, that this canal housed the glossopharyngeus nerve. Furthermore, in N. glacialis, the foramen usually referred to as the foramen for the œsophagus opens posteriorly into a cavity in the postbranchial wall, referred to here as the intramural cavity, and which is interpreted as having housed the heart. Consequently, the œsophagus probably accompanied the dorsal aorta through the aortic canal. Finally, the foramen generally interpreted as having transmitted the ventral afferent arterial trunk is here considered as having housed the hepatic vein, which emptied into the venous sinus of the heart. The ventral afferent arterial trunk may thus have passed through the former «œsophageal ›› foramen.
The problem of the position of the dorsal nerves in the Osteostraci is discussed, and it is suggested that the three foremost nerve canals opening into the oralobranchial cavity housed the maxillary ramus of the trigeminus, the facial nerve and the glossopharyngeus nerve respectively. The mandibular ramus of the trigeminus must have accompanied one of the two foremost nerves, but for the moment it is impossible to decide which.
The problem of the nature of the interbranchial crests of the Osteostraci is briefly discussed. Comparison with the branchial apparatus of the Petromyzontida does not support the hypothesis that the interbranchial crests are part of the branchial arches, incorporated into the endoskeletal shield. A different hypothesis is proposed, that the branchial skeleton of the Osteostraci was situated entirely inside the oralobranchial cavity, and was attached to the endoskeletal shield only by the ventromedial processes. The grooves classically allotted to the efferent branchial arteries would thus have housed extrabranchial arteries, branching off from the dorsal aorta, and irrigating the ventral branchial musculature.
A phylogeny and a classification of the kiaeraspidians are proposed. The evolution of this monophyletic group is characterized by, e.g., reduction of cornual processes, shortening of the abdominal division of the shield, subdivision of the lateral fields, and enlargement of the supraoral fossae.
The phylogenetic position of the kiaeraspidians within the Osteostraci remains uncertain. Their sister-group may be either the benneviaspidiens or the thyestidians, or Thyestes alone (in which case they would have to be included within the thyestidians). 

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 genus Plagiolophus is documented, almost solely in Western Europe, from the middle Eocene up to the mid Oligocene (MP 12 to MP 25), i.e. more than for 15 MY. Seventeen species are now recorded whose two of them are new, P. ringeadei nov. sp. and P. mamertensis nov. sp. Some anatomical variations and the deflection of certain evolutionary trends justify the distinction of three subgenera, Paloplotherium, Fraasiolophus nov. and Plagiolophus s.s. The genus displays a wide range in size and weight (between 10 and 150 kg). The detailed description of the skull of several species is here given for the first time.
Despite important evolutionary drifts during this long time span, the dentition shows a great structural homogeneity, which renders difficult the determination of fragmentary specimens or isolated teeth. It is characterized by a great heterodonty; premolars are little molarized and present a certain regression through time with paradoxically some progress in the molarization. The hypsodonty increases: the first Plagiolophus are hardly less brachyodont than Propalaeotherium, and the last ones are nearly as hypsodont as Merychippus from the early Miocene. The upper molars change from a wide crown pattern, with an open occlusal surface, lightly oblique transverse lophs and rounded internal cusps, to a narrower pattern, with a frontally constricted occlusal surface and internal lophs aligned parallel to the ectoloph. The M3/3 become always longer.

The dental enamel displays horizontal Schreger-bands with imprecise limits occupying only the middle part of the enamel layer. The dentine is remarkable by its high rate of pericanalicular dentine. The crown cementum, lacking in earlier forms, increases to the point where it fills the occlusal valleys of the
teeth.

The masticatory musculature shows a increasing prominence of the temporal, with probably an important role devoted to the pterygoid muscles in lateral movements related to a two-phase type of chewing.

The evolution of the dentition, of the masticatory musculature and of the repartition of masticatory forces indicate that the Plagiolophus have known different diets through their long evolutionary history; at first browsers they became mixed feeders and finally grazers. Their relatively long neck allowed these animals to reach different vegetal layers. The strength of the nuchal crests also suggests that they were able to have strong backwards movements of the head to pull up their food.

This evolution of diet seems related to the slow degradation of environmental conditions attested during this period in western Europe, with the generalization of more open landscapes, increasing aridity and more marked seasons.

Besides, a remodeling of the face is ontogenetically and along time observed, in relation with the evolution of the masticatory apparatus and especially with that of the mandibular lever arm. The postcanine diastemata become longer in the course of evolution; the free extremities of the nasals are always relatively long which contradicts the hypothesis according to which Paloplotherium may have had a trunk. At last the lineage Fraasiolophus can be distinguished by the presence of a deep malar fossa, probably related to a strong development of the maxillo-labialis superior muscle.

The orbit is always large and tends to increase in size, which indicates a good development of the vision and its increasing role in the life relations. A peculiar type of epitympanic sinus could have been used as a resonance chamber insuring a certain amplification of sounds before their transmission to the eardrum. The endocranial cast reveals a relatively large brain with an advanced degree of gyrencephaly. Beside the role eventually played in food research and social relations, these neurophysiological abilities, also related to an advance in cursorial fitness, could have contributed to the survival of these animals facing the predation pressure of the first fissipede carnivores and the competition with new immigrant herbivores after the "Grande Coupure".
On the basis of some shared apomorphies with the Pachynolophinae, which prevent from considering the latter as Equidae (molarization of the premolars, reduction of the premaxilla dorsal apophysis, peculiar epitympanic sinus, splitting of the jugular process), the hypothesis of an autochthonous origin of Plagiolophus issued from a form near Propalaeotherium, is once again proposed and discussed. Finally, intra-generic relationships are taken into consideration. 

In recent years, the techniques of chemical preparing have permitted a rich paleontologic material to be obtained from the phosporitic sediment of Bouzigues (Hérault, France). The fauna of this locality is comprised of quite varied microvertebrates, amphibians, reptiles, birds, mammals. Twenty five species of the latter, belonging to seven orders, are today known from the site. Among them, the numerous rodents have allowed L. Thaler to chronologically situate this fauna in the Zone of Laugnac (<< late Aquitanian ›> of some authors).
The chiropterans are, with the rodents, the best represented of the locality's mammals. Three families comprise the bat fauna, with nearly complete dominance by one of them (Hippoxideridae) over the two others (Megadermatidae and Vespertílionidae)
Six forms are described, of which three are new species and one a new sub-genus.
Megaderma braillomi n. sp., an animal of rather large size, shows like the Miocene megaderms several evolved dental characters, translating the adaptation of these animals to a partially carnivorous regime. The Bouzigues species seems, however, to represent a particular lineage.
Hipposideros (Brachipposideros n. subgen.) dechaseauxi n. sp. and Hípposideros (Brachipposideros) cf. collongenris Depéret, small sized forms, belong to a group rather well represented in the late Oligocene and early Miocene of Europe, and not distinguished until now within the genus Hipposideros.
Hipposideros (Pseudorhinolophus) bouziguensis n. sp., is the most abundant mammal in the locality and, occuring at the Oligocene-Miocene limit, the last representative known of the subgenus Pseudorhínolophus, common in Europe from the middle Eocene.
However, beyond Neogene and Quaternary times, certain among the numerous living species of Hipposideros are close to Pseudorhinolophus and others to Brachipposíderos. 'This fact would in the future justify a global revision of the genus, on the basis of comparative anatomy of the squeleton and of the teeth.
The bat fauna of Bouzigues is completed by two small Vespertilionidae, rare forms, Myoris sp. I and sp. II.
  

Abstract
 The validity of Propachynolophus Lemoine, 1891, supposedly an intermediate between Hyracotherium Owen, 1841 and Pachynolophus Pomel, 1847, has been questioned for a long time. A detailed analysis of features on which this genus is based further supported by a formal cladistic analysis demonstrates that Propachynolophus is not a valid taxon. The type species, “Propachynolophus gaudryi Lemoine, 1891” shall be assigned to Propalaeotherium Gervais, 1849, under the new combination Propalaeotherium gaudryi (Lemoine, 1891). “Pachynolophus maldani Lemoine, 1878”, later assigned to Propachynolophus, typifies the new genus Orolophus, under the binomen Orolophus maldani (Lemoine, 1878). The other referred species, “Propachynolophus levei Hooker, 1994” and “P. remyi Checa-Soler, 1997” are poorly documented, and both species shall be provisionally referred to as “Hyracotherium” levei (Hooker, 1994) and “Hyracotherium” remyi (Checa-Soler, 1997), pending new discoveries.
 
  

Situated in the Cape region of the Republic of South Africa (RSA), the paleontological site of Langebaanweg is dated to 5.1 Myr and is famous for having yielded an abundant vertebrate assemblage, including numerous rodent species from the Mio-Pliocene transition. Based on molar morphology and skull anatomy, the single Gerbillinae taxon identified at Langebaanweg and described in this paper is allocated to Desmodillus, which is a modern monotypic South African endemic genus. It is significant in being the oldest representative of the genus in Africa. We describe here a new species of this genus which is larger than the modern D. auricularis, but nevertheless retains some of its main characteristics, namely the shape of the maxilla and mandible, the presence of poorly fused alternating cusps, and no longitudinal crest. This taxon differs from modern South African Gerbilliscus representatives in some mandibular and maxillary characters, in the m1 prelobe cusp, and in having less fused cusps. Two fossil Gerbillinae discovered in the Upper Miocene of Africa and Asia, Abudhabia and Protatera, have been compared with the new species. We discuss their relationships with modern and Plio-pleistocene Gerbillinae and conclude that Abudhabia could be the sister taxon of Desmodillus and that around 6-5 Myr a vicariance event allowed Gerbillinae to diversify into modern Desmodillus in South Africa, and Gerbilliscus in East Africa. The murine/gerbilline ratio, which is a good indicator of rainfall, supports other proxies which suggest that at 5.1 Myr the climate in the Langebaanweg region was more humid than today. 

An unpublished mandible of the large hyracoid Titanohyrax andrewsi from the early Oligocene Jebel Qatrani Formation, Fayum Depression, Egypt is described. This specimen has a twofold importance. Firstly, it opens an unexpected window on early paleontological research in the Fayum because it was discovered as early as 1904 by the French paleontologist René Fourtau during an expedition to the Fayum organized by the Muséum National d’Histoire Naturelle, Paris (MNHN). This expedition has remarkably never been mentioned in the literature. Secondly, the mandible documents the best-preserved specimen of T. andrewsi, permitting a revision of one of the very rare Paleogene hyracoids. Interestingly, the new mandible was discovered two years before the first report of the species by Charles W. Andrews. The hypodigm of T. andrewsi is reviewed and the dentition as a whole is compared in detail, notably with other Titanohyrax species from the Fayum. The validity of the large Titanohyrax “schlosseri” species is discussed, but a pronounced sexual size dimorphism for T. andrewsi is favoured. 

Les Carnivores Fissipèdes de Sainte-Néboule appartiennent tous au genre Cynodictis et semblent constituer une population homogène. Celle-ci se distingue suffisamment des espèces déjà décrites pour constituer un taxon particulier : Cynodictis lacustris neboulensis n. s. sp. . L'étude des variations à l'intérieur de cette population nous a conduit à reconsidérer les critères utilisés pour définir les espèces existantes et à regrouper certaines d'entre elles. Il semble qu'il demeure cependant trois lignées distinctes dans le genre Cynodictis mais le matériel nous paraît encore insuffisant pour traduire cette remarque en termes de systématique. 

     The Faunas of Rodents from seven north-african fossiliferous beds distributed from the Middle up to the Uppest Miocene are studied. One genus, seventeen species, one subspecies described are new.
       A detailed description is given of the evolution of the numerous specific lines, systematic groups and communities. The evidence of the strong endemism of the North African faunas of that time compared with those of Europe as well as of Tropical Africa is clearly shown. Special relationships with Asia clearly also appear, mostly in the Middle Miocene and the beginning of the Upper Miocene.
       Using the specific lines with a biostratigraphic purpose gives the opportunity to establish a biochronological scale for the continental formations of the Maghreb. This scale is calibrated by a few absolute datations. These datations, as well as the stratigraphical study of several fossiliferous localities have given the possibility to establish precise correlations with the corresponding scales of Europe and of Tropical Africa, as well as with the marine formations of the Neogene of occidental Mediterranean sea.
       The paleoclimatic data connected with this period in North Africa are explained and the contribution of the micromammals is discussed. 

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. 

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 middle Palaeocene of São José de Itaboraí (State of Rio de Janeiro, Brazil) has yielded a very rich and diverse snake fauna which includes Madtsoiidae, Aniliidae s.l., Boidae, Tropidophiidae s.l., Booidea incertae sedis, and Russellophiidae. The present article (part I) deals with Madtsoiidae and Aniliidae s.l. Madtsoiidae are represented by many vertebrae and a few skull bones. They comprise one new species assigned to the genus Madtsoia (M. camposi sp. nov.). However, the definition of the genus Madtsoia is unsatisfactory and the generic allocation might be provisional. A few elements, vertebrae only, belong to the Aniliidae s. l. Two taxa are referred to this latter group: Coniophis cf. C. precedens and Hoffstetterella brasiliensis gen. et sp. nov. The forthcoming part II will deal with Boidae.

  

Of the ten cricetid species from the Oligocene of Western Europe, attributed until now to the genus Eucricetodon, only four prove to be utilizable - E. atavus, E. huberi, E. praecursor, E. collatum - to which it is possible to add two forms newly described: E. huerzeleri and E. quercyi. The evolullon of the genus Pseudocricetodon is also the subject of new observations. The study of the dental morphology allows us to distinguish in these two genera three lineages beginning in the middle Oligocene:

- Lineage P. montalbenensis-P. thaleri (from Montalban to Goderet), of small size, without
increase in size.
- LineageE. atavus-E. infralactorensis (from Hoogbulsel to Estrepouy), of middle size, with a regular increase in size.
- Lineage E. huerzeleri-E. haslachense (level of Montalban to that of Estrepouy), of large size, with an increase in size.

Two other forms are equally represented in these loealitles: Heterocricetodon aff. helbengi and Melissiodon quercyi. It has been possible to attribute a precise age (zone of "Cournon") to the last species, which has been defined by Schaub (l925) from material in the Old Quercy collections. The genera Pseudocricetodon, Eucricetodon, ? "Cricetodon", Leydimys, Eumys, differentiated at the beginning of the middle Oligocene in Europe, Asia and North America, seem to derive from a common ancestral group. The place of origin of this group could be situated in Asia. 

Deux types de remaniements post mortem me paraissent caractéristiques de l'état de conservation des dents de mammifères fossiles dans les Phosphorites du Quercy :

1) Des destructions localisées d'origine biologique, sous forme de galeries de morphologie très variable creusées dans la dentine et le cément, et impliquant sans doute la participation de différents types de micro-organismes. Ces altérations se sont développées peu de temps après la mort, avant la fossilísation proprement dite et se sont rapidement arrêtées après l'enfouissement dans le sédiment phosphaté.

2) Des perturbations dans les structures de la dentine liées aux variations locales de minéralisation, provoquées par une imprégnation diffuse des zones les moins calcifiées par divers minéraux et probablement surtout de l`apatite. 

The presence at Silveirinha of one of the earliest, ? Late Paleocene or Lowermost Eocene, european representatives of the genus Diplocynodon is based mostly on isolated bones and teeth (often from juveniles). This small-sized form is the only crocodilian so far recognized in this site. The longevity of Diplocynodon in Portugal becomes much extended; the genus survived there until the Middle Miocene at least. A discussion on the possible affinities with other eocene Díplocynodon and especially those from Cubillos-Valdegallina (Zamora, Spain) is presented. On the other hand, differences have been detected in comparison with: Díplocynodon tormis, from the middle Eocene of the Douro basin in Spain, which may belong to another phyletic line; and the aff. Diplocynodon from Dormaal (Belgium) and Le Quesnoy (France), nearly contemporaneous of Silveirinha. The Silveirinha Diplocynodon and many other data strongly suggest moist, subtropical, quite limited in space environments related to an alluvial plain crossed by small, meandering channels.