The early gnathostome genus Mesacanthus is well represented in both Lower Old Red Sandstone and Middle Old Red Sandstone assemblages of northern and central Scotland. This ‘acanthodian’ taxon is currently thought to comprise two valid species: M. mitchelli and M. pusillus. Although the whereabouts of the holotype of M. mitchelli (NHMUK PV P560) is known, the syntype material for M. pusillus has long been thought lost. Here we identify at least one specimen that formed part of the original syntype material for M. pusillus, albeit in a slightly different condition than when it was originally figured. This specimen is ROM 25872, which is here designated as the lectotype. A second specimen – ELGNM 1978.191.1 – could represent another of the syntype specimens, but poor preservation quality makes it impossible to be certain. 

Some complete tooth rows and about one hundred isolated teeth enabled the identification of the deinothere of the Vallesian site Montredon (Hérault) as Deinotherium giganteum KAUP 1829, mainly by comparisons with the likewise Vallesian sample of the type locality Eppelsheim (Rheinhessen, F.R.G.).
Scatterdiagrams of the teeth show the importance of allometry during the phyletic size increase of the European deinotheres.
Some taphonomic problems of the Montredon deinothere are briefly mentioned. 

Revision of the Tayassuidae from the old collections of the Quercy leads to interesting facts about taxonomic and phylogenetic problems. It could not have been well done without constant comparison with contemporaneous Tayassuidae from stratified series, as well as with European Miocene Tayassuidae and Hyotheriinae. The result is that only three species are present in the Phosphorites of Quercy: Doliochoerus quercyi FiLHOL (represented by two sub-species: the older, D. quercyi quercyi and the more recent, D. quercyi aquensis), Palaeochoerus gergorianus CROIZET et BLAINVILLE and Palaeochoerus purillus nov. sp. The two former species disappeared with Stampian time, while the third is the direct ancestor of the Aquitanian Palaeochoerus typus POMEL, which became extinct before the beginning of Burdigalian.

The comparison with Hyotheriinae brought to light new criteria for determinations, based on the study of lower premolars. These observations are condensed in a table of keys for determinations.

As a result of these studies, it came to light that the Suoidea of the Oligo-Miocene of Europe have never given rise to, except in rare cases, very long lineages. The different forms of pigs are replaced constantly in Europe by the simple game of extinctions and migrations. The reason of that discontinuity is considered here. 

An increasing fossil record of dinosaur eggs and eggshells allows putting ootaxa within a chronostratigraphic framework, in order to study their distribution pattern leading eventually to their use as biochronological markers. For these purposes, high-quality data exists in four major regions; North America, South America, Europe and Asia (Central Asia and India). Most of the highly diverse dinosaur egg record has been dated as Latest Cretaceous in age (Campanian-Maastrichtian), reaching the Cretaceous-Tertiary boundary closer than the dinosaur bone record. However, dating continental sections is problematic and need to be carefully verified, as it appears when comparing the European dinosaur eggshell record from two well-studied areas. Ootaxa distribution in both sides of the Pyrenees (Tremp and Aix basins) shows comparable oospecies successions, but different chronology. This disagreement probably indicates that one or both successions have a wrong chronostratigraphic calibration.  

A short review of the genera and species of snakes from the Quercy's phosphorites described by former authors is followed by the study of specimens recently collected. Most of these latter specimens belong to the Aniliidae, Boidae, Colubridae and to the Scolecophidia; the precise systematic position of some of them is not defined yet. The following genera and species are described: Eonilius europae nov. gen. and nov. sp., Platyspondylia lepta nov. gen. and nov. sp., Coluber cadurci nov. sp. and Dunnophis cadurcensis nov.  sp.; a species described by de Rochebrune (Palaeopython filholi) is revised. One of the most important conclusions of this study is that the Colubridae appear as early as the Upper Eocene. The stratigraphic repartition of these snakes shows that the rich Upper Eocene fauna is followed by the very reduced fauna of the Lower Oligocene; then the oligocene «Grande Coupure» corresponds to a very important faunistic renewal. The fauna remains poor and little diversified during the beginning of the Middle Oligocene after which there is a new faunistic explosion. 

Voici une centaine d'années débutait sur les Causses du Quercy l'exploitation des phosphorites qui devait permettre d'amasser des collections de Vertébrés fossiles uniques au monde. Ces fossiles firent l'objet de nombreuses publications et les noms de Filhol, Gaudry, Schlosser, Stehlin, Teilhard de Chardin sont attachés à ces premières études.

Après quelques années de prospection, les fouilles dans le Quercy ont repris en 1965, organisées par les laboratoires montpelliérains et parisiens. Ces premières recherches ont été aidées par le Centre National de la Recherche Scientifique qui a organisé une « table ronde» pour faire le point des premiers résultats obtenus. Ceux-ci ont été jugés suffisamment prometteurs pour que le C.N.R.S, ait décidé de poursuivre son effort par l'intermédiaire d'une Recherche Coopérative sur Programme.



  

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. 

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.

  

The comparative morphology and biometry of the lower cheek teeth of modern Equus are studied on approximately 300 mandibles belonging to the 10 usually recognised species : Equus grevyi, E. burchelli, E. quagga, E. zebra, E. africanus, E. asinus, E. hemionus, E. klang, E. przewalskii, E. caballus. The studied parameters comprise : occlusal length and width, postflexid length and index ; shape of the double knot (metaconid + metastylid + lingual groove) ; depth of the vestibular groove on the molars ; frequency of the pli caballinid, protostylid and other enamel plications or islets ; frequency of the dP/l.
The same methods of study are applied to a number of North American, Eurasian and African species. For the sake of comparison, some Hemphillian equids were observed (Dinohippus interpolatus, Dinohippus leidyanus, Astrohippus ansae, Phiohippus mexicanus) but most of the discussed material belongs to Pliocene or Pleistocene species of Equus : the « stenonine ›› E. stenonis, E. simplicidens, E. sanmeniensis and E. teilhardi; the « caballine ›› E. scotti, E. lambei, E. Iaurentius, E. mosbachensis, E. germanicus, E. gallicus, E. taubachensis and the Liakhov horse. The relationships of other species, in particular the North American E. calobatus, E. occidentalis, E. cf mexicanus are not clear for the moment. ln Africa, the Plio-Pleistocene species from Koobi Fora (Kenya) show some stenonine and perhaps asinine affinities. The relationships of E. numidicus and E. tabeti are uncertain but these species are probably related to the East African ones. E. mauritanicus is most certainly related to the Quagga group.
The biometrical data are gathered in 32 tables ; 4 photographie plates and 19 figures illustrate the next. The whole is a complement of the previously published studies of the skulls, upper cheek teeth, incisors and metapodials of modern and fossil Equus.

  

Le présent volume est l'aboutissement d'un projet né il y a presque cinq ans. En décembre 1991, l'un d'entre nous (MG) prenait des contacts en vue de proposer un symposium sur les mammifères fossiles, dédié à D.E. Russell, dans le programme du 4e Congrès de la European Society for Evolutionary Biology. Ce congrès, baptisé "Evolution 93", devait se tenir à Montpellier en août 1993. Son Comité d'Organisation, animé par F. Catzeflis, recherchait des organisateurs de symposiums. L'idée fut acceptée avec enthousiasme par le second d'entre nous (PDG), et le titre de notre Symposium fut précisé: " Palaeobiology and Evolution of Early Cenozoic Mammals - A Symposium in Honor of D.E. Russell". Le projet fut formellement accepté par le Comité d'Organisation en avril 1992. 

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. 

A general view is given of the vertebrate faunas, Cretaceous to Quaternary of age, found in Columbia and of their principal characteristics. This view leads to the discussion of the isolation of the South American continent and of the role played by the Bolivar syncline with respect to North American immigrants during the Oligocene. The absence of marine deposits of Oligocene age in the north and northwest of Columbia suggests the possibility of a communication with Central America. This communication would have permitted the passage of hystricomorph rodents, of platyrrhine monkeys, and of colubrids. The non-occupation, until then, of the ecologie niches of these groups would have favored their installation beside the indigenous fauna. In this hypothesis it would no longer be necessary to admit that these vertebrates arrived as «island hoppers ››. The eco-biologic conditions would explain the absence of large-sized forms of North American origin. 

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. 

The eggshell of Nicobar scrubfowl (Megapodius nicobariensis) is described for the first time. Its egg porosity is calculated and discussed with data from several taxa (another megapode, some extant and fossil reptiles including a titanosaur group) in order to compare incubation types with eggshell structure. Eggshell microstructure reflects first phylogenetic traits and does not seem to have developed major adaptative features due to the incubation conditions, except for the pore canals. 

The teeth and the astragale of the Creodonta from Ste-Néboule (Lot) are referred to Hyaenodon brachyrhynchus. Isolated teeth fit morphologically the material from La Débruge (Middle Ludian). However, biometric analysis suggests an Upper Ludian age. 

The Squamates from Sainte-Néboule are charateristic of the Upper Eocene from the Phosphorites du Quercy. Most genera known from this locality do not survive the « Grande Coupure ». Cadurcoboa insolita gen. nov., sp. nov. is a small Boidae very characteristic of the Upper Eocene. 

Revision of the hipparion material from Montredon, including newly excavated and other unpublished specimens brings evidence of specific heterogeneity.
A fragmentary very small MC III seems very close to H. macedonicum from the upper Vallesian of Ravin de la Pluie, Greece. In that same site was also found a large hipparion.
Most of the Montredon material is referred to H. depereti. This species associates characters usually found in Vallesian hipparions (highly plicated upper cheek teeth, deep vestíbular grooves on the lower cheek teeth, robust metapodials) with characters more frequent in Turolian forms (middle size, lack of confluence in the upper premolar fossettes, lack of ectostylids on the adult lower cheek teeth, well developped keel on the MC III, facette for the 2nd cuneiform present on all MT III). H. depereti shares some of these characters with the Spanish and Portuguese hipparions transítional between the Vallesian and the Turolian (Masia del Barbo, Azambujeira) but is not identícal to any of them. The upper Vallesian hipparion material from Diavata, Greece, probably belongs to H. depereti but not the large hipparion rests from Ravin de la Pluie.
Thus, Montredon and Ravin de la Pluie may well share the same small species, H. macedonicum, but they differ in the associated one: middle-sized H. depereti at Montredon, large-sized H. primigenium at Ravin de la Pluie. Both sites, however, give evidence of small hipparions during the Vallesian, coexisting with other larger species.
The present paper also proposes an adaptation of the Kiesewalter's indices that calculates the height at the withers using the metapodial length, and discusses indices proposed by Gromova and by Sen et al. to express the relative development of the metapodial keel. 

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. 

New records of terrestrial mammals from the Qasr el Sagha Formation, Fayum Depression, Egypt are reported, and the stratigraphic occurrences of these fossils noted. These include additional specimens of Moeritheríum, Barytherium, and anthracotheres, as well as the oldest record of a hyracoid in the Fayum.These Eocene mammals occur almost exclusively in the alluvial deposits of the Dir Abu Lifa Member of the Qasr el Sagha Formation and show close affinities to the faunas from the lower sequence of the Jebel Qatrani Formation. There is no evidence of a more marked faunal discontinuity between the Qasr el Sagha and Jebel Qatrani Formations than there is across any of the three major breaks in sedimentation that exist within the Jebel Qatrani Formation. The faunal similarities between fossils of the lower sequence of the Jebel Qatrani Formation and of the upper part of the Qasr el Sagha Formation is consistent with recent paleomagnetic dating that suggests that these rocks differ in age by only one to two million years. 

The formic acid preparation of a nodule collected from the Lower Triassic of Spitsbergen, and containing a skull with some associated postcranial elements of Lyrocephaliscus euri (WIMAN), precises and enriches previous descriptions of the reputedly well-known trematosaur. lt permits more detailed descriptions of the occipital region, of the course of the carotid arteries and collateral vessels, and refutes the previous description of a stapedial foramen in trematosaurs. The discovery of pleurocentres associated with the other vertebral components confirms the primitive rhachitomy of trematosaurs.