L'exploitation des phosphates s'est produite surtout de 1890 à 1914 de Saint-Antonin à Cajarc, sur le Causse de Limogne, dont l'histoire géologique et morphologique peut expliquer les conditions de gisement du minerai, et aussi la découverte des nombreux, variés et beaux fossiles qu'on a extrait des poches en même temps que la phosphorite. Le Causse de Limogne est le nom donné par les géographes au plateau calcaire, faisant partie des Causses du Quercy, et compris entre la vallée du Lot au Nord et celle de "Aveyron au Sud". En fait, le nom de "causse" désigne localement un terroir, un paysage, à sous-sol de calcaire, à sol peu épais, qui s'oppose aux sols argileux des « terreforts » et aux sols légers et profonds des "boulbènes". Chaque communauté agricole distinguait ainsi son causse, par exemple le causse de Caylus, le causse de Limogne ou le causse de Cajarc. C'est par extension que l'appellation Causse de Limogne désigne tout un petit pays. La présence des poches à phosphate déborde un peu vers le Nord la vallée du Lot, et vers l'Est le Causse de Limogne proprement dit (Causse de Villeneuve).   

Aside from Madtsoiidae, anilioids, and Boidae that were studied previously, the middle Palaeocene of ltaborai (BraziI) has produced Ungaliophiinae ("tropidophiids"), booid-grade snakes incertae sedis, and a possible Russellophiidae (Caenophidia) that are described in the present article. This article is the third and final report on the snakes from the locality. The Ungaliophiinae (Paraungaliophis pricei gen. et sp. nov.) are rare whereas the booid-grade snakes incertae sedis (ltaboraiophis depressus gen. et sp. nov., Paulacoutophis perplexus gen. et sp. nov.) are more frequent. A single vertebra is referred to the Russellophiidae (Caenophidia) with reservation. An update of the whole fauna of snakes from ltaborai is provided. Hechtophis austrinus that was tentatively referred to the erycine Boidae is now regarded as a Boidae incertae sedis. Most snakes from Itaborai are known only from the locality. Astonishingly, only the ailioids Coniophis cf. C. precedens gives possible evidence of interchanges between South and North America. The fauna of snakes from Itaborai, as well as the other Palaeocene faunas of snakes from South America are distinct from those of the Cretaceous and the Eocene of South America; they appear to be more different from the Cretaceous faunas than from those of the Eocene. The fauna from Itaborai is the richest and most diverse assemblage of snakes from the Palaeocene worldwide; it shares only a few taxa with other Palaeocene localities. 

The Arvicolid evolution results in an increase of the dental structure complexity. The M3/ differenciation seems to characterise the tribe subdivisions, that of M/1 being variable from one to another lineage. The phyletic relationships of fossil lineages are discussed from a paleogeographic point of view. 

The first part of this study was devoted to a descriptive analysis of teeth morphologies among the vespertilionine bats. This leads now to a tentative synthesis, providing views on the systematics of the group. The results could be seen according to three distinct but closely related purposes : 1 - the sorting of the genera contents in order to conform the genera units to homogeneous taxa that could represent natural issues of evolutionary lineages ; 2 - the investigation of relationships between extant genera in order to infer the possibilities of common origin ; 3 - according to the preceeding items and to the observed evolutionary trends, a tentative phylogeny, modest and cautious. The contents of many genera are sorted : Leuconoe is removed from subgeneric to generic position, whereas Myotis becomes a subgenus of it ; the myotodont species are cleared away from the Pipistrellus genus ; Glischropus and Scotozous are synonymized within Pipistrellus ; Hypsugo is raised to the generic level ; some species previously ranged within Pipistrellus will form provisionally a collective group, Attalepharca nov. ; the Eptesicus genus is broken up, the excluded species being grouped within Nycterikaupius gen. nov. ; the Nycticeini tribe is defined again after exclusion of Otonycteris , Scotoecus, Scotophilus , and addition of Hesperoptenus ; the species la io and Pipistrellus tasmaniensis are removed to Eptesicus (n.s.) and Pipistrellus dormeri to Scotoecus. Groupings of genera are stated according to the main evolutionary trends of I1/. The relevance of these is often warranted by close morphologic similarities of other teeth. This leads to a recognition of the major evolutionary radiations which occurred in the group. The filiations schematized at the end of the work show the dental relationships observed between the extant genera, and could represent a phylogenic framework. Two major facts are to be underlined : 1- the early divergence of leuconoids ; 2 - the successives crossings to myotodonty from the nyctaloid flow. Fossil data from the literature are punctually and tentatively incorporated within phylogenic sketches. 

New populations of the genus Megacricetodon have recently been discovered in Southern France.Two new species are defined: M. lemartineli n. sp. and M. fournasi n. sp., their stages of evolution are intermediate between those of M. gersii and M. roussillonensis. Morphological and biometrical analysis indicate the presence of only one lineage: M. collongensis--M. collongensis-gersii--M. gersii--M.lemartineli nov. sp.--M. fournasi nov. sp. and M. roussillonensis. This observation allows to refine the chronology based on rodents, for the Late Early Miocene and the Middle Miocene in the Southern France.
Comparisons with some iberian species are done. The validity of the French species M. bezianensis and M. bourgeoisi is discussed. 

Pour la première fois un spécimen de lagomorphe a été récolté en Quercy. L'intérêt de ce fossile tient surtout à son âge géologique inattendu, qui recule considérablement la date de première apparition en Europe de cet ordre de mammifère, Ceci nous paraît justifier une nouvelle réflexion sur la « grande coupure» oligocène, 

Functional morphology invertebrate paleontology, édité par Jeffrey J. THOMASON, 1995. Cambridge University Press, xi + 277 p. ISBN 0-521-44095-5, f. 45,00 ($ 69,95).

La morphologie fonctionnelle appliquée aux fossiles demeure un sujet à la fois passionnant et important. Passionnant, car elle s'adresse à des êtres disparus, aux combinaisons de caractères parfois inattendues et sans contrepartie chez les formes actuelles. Sujet important, car il faut, au delà de la constatation classique de l'adéquation de la forme des organes à leur fonction, expliquer l'origine des structures par évolution. L'évolution ou descendance avec modification, implique que les êtres vivants sont reliés les uns aux autres et qu'i! est possible de tenter à l'aide d'un raisonnement par inférence, la caractérisation des ancêtres en fonction des traits des formes auxquelles ils ont donné naissance. Mais il faut ajouter que par sa fonction, la structure relie immédiatement l'animal à son milieu puisqu'elle assure un rôle biologique. 

Le Quercy est aujourd'hui un vaste plateau calcaire, parcouru par un réseau karstique actif, pro· fondément entaillé par des vallées aux falaises abruptes, comme celles du Lot ou du Célé. Sur un sol peu épais domine la forêt de chênes, accompagnés de cornouillers, érables, genévriers. La faune est pauvre, peu diverse, et les nombreux chasseurs se satisfont de gibier d'élevage ...
Il y a trente-cinq millions d'années environ, le paysage était bien différent. La période de l'Eocène supérieur, qui s'achevait, avait été chaude et humide, si l'on se réfère à la fois aux paléotempératures (calculées à partir de sédiments marins extra-européens) et aux restes fossilisés de végétaux typiquement tropicaux.
Le Causse du Quercy devait être un plateau très disséqué par la karstification, à surface lapiazée creusée de gouffres en rapide évolution interne, et couvert d'un sol assez épais. Une forêt tropicale humide, avec notamment des Myricacées et des gymnospermes, recouvrait l'ensemble du pays, à peine interrompue au niveau des rares points d'eaux situés dans les bas-fonds. Dans ce cadre vivait une faune considérablement différente de la maigre faune actuelle. Si nous pouvons l'imaginer, c'est grâce aux cadavres des animaux entraînés dans les cavités par les eaux courantes ou les prédateurs, ou bien logeant et mourant dans les milieux souterrains. Nombre de ces restes, fossilisés, sont parvenus jusqu'à nous et sont aujourd'hui l'objet d'étude. 

The study of dental variations in Landenodon from Dormaal (early Eocene, Belgium) shows that only one
species is present in this locality : L. woutersi QUINET, 1968 (Condylarthra, Arctocyonidae, Arctocyoninae). A high morphological variability is described, especially concerning the metaconid of P/4, the paraconid of M/2, and some characters of M1/ which have been found to be independant of each other. This variability is discussed. 

Palaeotis weigelti, from the Middle Eocene of central Europe, is a flightless, paleognathous bird. It appears to be a member of the ostrich lineage on the basis of trivial derived characters. It is a very primitive ratite, however, and does not possess any of the highly specialized cursorial adaptations that characterize the modern steppe -and savanna- dwelling ostriches. 

The revision of the Rhombodontidae from the Maastrichtian of Morocco led us to the description of a new species: Rhombodus andriesi.

The biometrical study of populations of R. binkhorsti and R. microdon, species sometimes considered as synonymous, supports the conclusion that they represent two distinct species and not young and adult specimens of a single species. The stratigraphical range of these two species confirms this
result.

The reexarnination of type-series studied by C. Ararnbourg led us to revise the generic status of Rhombodus bondoni which is now ranged, because his dental features, in the new genus Dasyrhombodus showing a less derived dentition than Rhombodus. The stratigraphical range of each species is clarified within the phosphatic series. 

The tooth morphology of the Thalattosuchia (marine crocodilians from the Jurassic and the Early Cretaceous) is analysed. The Callovian from Poitou and the Kimmeridgian from Quercy have yielded many remains of Metriorhynchus, Steneosaurus and Machimosaurus. These remains allow us to study the variations of tooth morphology during ontogenic growth, tooth replacement and the location of the teeth. We have defined different tooth types for these genera. In Metriorhynchus, the two tooth types defined do not coincide with the two groups recognized in the Callovian (broad-skulled and narrow-skulled metriorhynchids) but reflect the prey preferences of these forms. In Steneosaurus and Machimosaurus the five tooth types deñned are in agreement with the main taxa known from the Bathonian to the Early Cretaceous. This study allows to precise the function and the prey preference of the Thalattosuchia during the Jurassic and the Early Cretaceous.

  

The Late Triassic locality of Saint-Nicolas-de-Port (Meurthe-et-Moselle, France) has yielded numerous isolated teeth belonging to archosauriform reptiles. The following tooth groups can be identified: heterodont phytosaurs, the pterosaur Eudimorphodon, the prosauropod dinosaur Plateosaurus, three types of putative ornithischian teeth and 13 types of carnivorous Archosauriformes indet. Apparent venom-conducting teeth belonging to a new taxon of ?Archosauriformes (Graoullyodon hacheti nov. gen. nov. sp.) are also described. From a palaeogeographical point of view, the ornithischian teeth from Saint-Nicolas-de-Port (if their attribution is confirmed) are the oldest fossils of this group in Europe. The biostratigraphic distribution of the tooth forms mostly suggests a Late Norian or Early Rhaetian (depending on current interpretations) age of the deposits, but do not provide more precisions than fossils previously described from the area. The dietary habits and, consequently, the palaeoecological relationships of the different vertebrate groups discovered at Saint-Nicolas-de-Port are tentatively established: the ornithischian and prosauropod teeth reflect a herbivorous diet, whereas the other archosauriform teeth are probably from camivores or omnivores.

  

A new genus and species of haplobunodontid artiodactyl, Hallebune krumbiegeli nov. gen. nov. sp., is described from the middle Eocene Geiseltal Fauna (Saxon-Anhalt, Germany). Its stratigraphic range is restricted to the MP 13 ("obere Mittelkohle") of the Geiseltalian. The material consists of seven fragments, representing both upper and lower jaws. It is indicated, that H. krumbiegeli was a small bunodont herbivore. The size and primitive character of the teeth suggest that the genus possibly is directly derived from Diacodexeidae.The new material forms the basis for reinterpreting the haplobunodontid phylogeny. 

Two species lineages of North American late Paleocene Plesiadapis exhibit a pattern of size divergence from a common ancestral lineage. Time series of fossils in each of these lineages are analyzed to test the idea that size divergence represents competitive character displacement. The critical factor in a test of character divergence is showing that divergent lineages evolved directionally rather than randomly (multifactorially). Analysis of evolutionary rates and their temporal scaling in Plesiadapis shows that both divergent species lineages have the scaling slope expected for lineages evolving randomly rather than directionally, and size divergence in Plesíadapis does not represent character displacement. Rates of evolution commonly observed on a per-generation time scale are high enough to produce character displacement within a few generations. Thus character displacement is not likely to be visible on scales of time that can be studied in the fossil record. 

We experimentally explore the early taphonomic stages involving the decay and biodegradation of buried eggs and eggshells. Unfertilised commercial chicken eggs and eggshell fragments were buried in plastic containers and were kept under controlled conditions for eight months. Half of the containers were filled with marl, and the remainder with sand. All were saturated with fresh tap water, acidified water, sulphate water, or seawater. They were kept in the dark at 23.4-26 °C, except one, which was kept in a heating chamber at 37.4°C. We expected that different burial conditions would produce distinct taphonomic outcomes. Instead, the taphonomic alterations of buried eggs parallel that of the alteration of egg proteins (i.e., denaturation and/or putrefaction) with an additional role played by the eggshell. Mummification, encrustation, distortion and fragmentation, and necrokynesis (vertical displacement) depend on organic matter decay. The experiment identifies environmental conditions that may favour or actively promote these taphonomic processes. Of these, early pyritization is one of the most relevant. For comparative purposes, samples of fossil and extinct eggshell representing three distinct environmental burial conditions were examined. These included Megaloolithus, Caiman crocodilus, and Struthio camelus ootypes. The geochemical analysis of these eggshells showed no significant differences among the chemical variables of these fossil and extant ootypes. Eggshells exhibited a stable composition over a range of experimental conditions. 
  

Fossils of the Trionychidae, Bataguridae or Emydidae, Palaeophis and Crocodylia from Chattahoochee, NW Florida, USA, represent the first report of an Eocene reptile fauna from Florida. 

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. 

Editorial for celebrating the publication of the volume 20.

La revue PALEOVERTEBRATA a été fondée en 1967 par Louis THALER, à une époque où il n'existait, au plan international, que deux périodiques uniquement consacrés aux vertébrés fossiles. Actuellement ce nombre n'est que de quatre. A l'origine la revue fut essentiellement créée pour diffuser les résultats des chercheurs du Laboratoire de Paléontologie de l'Université de Montpellier, alors en début d'expansion et plusieurs thèses et de nombreux travaux directement liés à des thèses y furent publiés ce qui n'excluait déjà pas la publication d'articles d'auteurs étrangers.
[...] 

The St-Dézéry local fauna (3 reptile-, 4 mammal species) is approximately of the same age as the La Débruge or the Ste-Néboule faunas. It conduces to a better dating of the limestones underlying the Célas sandstones. A large part of a mandible of Amphimeryx was found there, which documents the record of this family of small artiodactyls