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.
[...] 

Afin d'étudier la magnétostratigraphie de la colline de Montredon, j'ai prélevé en Avril 1982, 93 carottes orientées réparties sur 29 sites. J.-P. Aguilar et I. Loridant m'ont aidé durant cette opération. Pour la stratigraphie de la coupe échantillonnée et pour le contenu faunique des deux gisements de mammifères de cette colline, voir J.-P. Aguilar & J.-Y. Crochet (1982).
[...] 

The Paleogene faunal assemblage from Antofagasta de la Sierra (Catamarca, Argentina), is here presented, both in its geological and systematic aspects. The fossil bearing levels are referred to the Geste Formation (Pastos Grandes "Group"). The described specimens belong to the Classes Reptilia (Orders Crocodylia, Serpentes and Chelonii) and Mammalia (three taxa from the Superorder Marsupialia, representatives of the Orders Edentata, Condylarthra, Pyrotheria and Astrapotheria, and six families of the Order Notoungulata). This fauna is referred to the Mustersan Age, which in Patagonia represents the Middle Eocene. Such chronologic assignment is based on the presence of characteristic taxa, their evolutionary stage and on stratigraphic evidence. Finally, a brief comparison with other faunal assemblages from the Early Tertiary of Argentina and Chile, is presented. 

Revision of ancient collections and study of new material from Provenchères-sur-Meuse (Rhaetian) lead to signíficant changes in the faunal list of this site. This bring to us important information about the effect of the rhaetian transgression on the evolution of the faunas at this period of time. However, study of
vertebrate microremains is always difficult and some points remain obscure, like the origin of the prosauropods which yield some remains at Provenchères-sur-Meuse and the survival in Europe during the Rhaetian of temnospondyl arnphibians different from the Plagiosauridae.

  

Le premier Symposium International sur les ceufs de dinosaures et leurs petits a connu un francs succès, à Isona, en Catalogne (Espagne) en 1999. I1 faisait suite à la publication en 1994 d'un premier ouvrage "Dinosaurs eggs and babies" édité par K. Carpenter, K. Hirsch et J. Homer. Entre 1994 et 1999, les nouvelles découvertes ont augmenté significativement, notamment celles d'ceufs embryonnés, et le nombre de chercheurs impliqués dans ce domaine a accompagné cet accroissement. Jusque là, l'étude de ces objets, les coquilles d'ceufs, est restée longtemps marginale, faute d'une méthodologie scientifique appropriée. 

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. 
  

ATLAS OF MESOZOIC AND CENOZOIC COASTLINES, par Alan G. SMITH, David G. SMITH & Brian M. FUNNELL, 1995. Cambridge University Press, 99 p., 31 cartes, 3 tab!., 2 fig. ISBN 0-521-45155-8.

L' "Atlas of Mesozoic and Cenozoic coastlines" succède avec bonheur aux "Mesozoic and Cenozoic paleocontinental maps" de Smith & Briden, publié en 1977. 

A rear skull from the Quercy Phosphorites is described. It documents a new perissodactyl genus, likely assignable to the family Palaeotheriidae and probably paleogene of age. Owing to the lack of any tooth, this family assignment remains however somewhat hypothetical. The specimen is firstly characterised by the presence of a wide epitympanic sinus swelling and hollowing the squamosal shell and the post-glenoid process. This cavity might make up a peculiar pattern of improvement for the hearing apparatus by carrying out a kind of drum near the middle ear, whereas the bony tympanic remains barely bulged and forms but a few developed auditory bulla. This pattern appears an outcome of a trend observed with many palaeotheriids, such as Plagiolophus. Furthermore, the endocranial cast shows a rather high degree of gyrencephaly for a paleogene mammal. The prominent lambdoidal crest points out a powerful nape musculature and a lowered head bearing. Consequently, it is assumed that such an animal was probably living in somewhat open places, at the expense of rather tough vegetables. It might have been accordingly provided with a semi-hypsodont, cement covered, "plagiolophoid" dentition. 

The oldest european marsupials are described from some specimens (isolated upper molars) recently found from the Hainin sediment (Middle Paleocene of Belgium). These fossils document a new species of the Peradectes genus. They give evidence of a much older occurrence of the marsupials in Europe than it was assumed. They allow us to postulate a didelphid dispersal from South America towards the western-holarctic area operating in two phases : the first one of the Peradectes genus at the end of the Cretaceous; the second one of the Didelphíni tribe at the end of the Paleocene. A central american crossing is likely for the first one,  whereas a transafrican way is tentatively argued for the second one. 

Several different taxa of jawed vertebrates are reported for the first time from the Devonian of south-eastern Montagne Noire, France. Besides some undeterminable fragments of placoderm fishes from the Pragian and Lower Emsian, the material from the Upper Devonian is mainly represented by Melanosteus occitanus gen. and sp. nov. (Frasnian) and Thoralodus cabrieri LEHMAN, 1952 ("Famennian"). The good state of preservation of Melanosteus allows a detailed anatomical study leading to a phylogenetic analysis of the selenosteid pachyosteomorphs. 

Systematische Zoologie by A. REMANE, V. STORCH, and U. WELSCH.
1986, Edition 3. Cloth and paperbound. Stuttgart and New York : Gustav Fischer Verlag.
xvi + 698 pp. DM 86. (Geb.) & DM 72 (kart.). 

Besides Dendromurids and Murids, the Chorora Rodents include 7 taxa, two of which are new. Afaromys nov. gen. is a Cricetodontine with very complicated lower molars, certainly isolated for a long time from Eurasian species. A Paraphiomys, with tetralophodont upper molars, is also quite different from other East African species, and its roots should probably he searched in the middle Miocene. Other taxa are less original, and more similar to the South Asiatic ones. 

Murids and gerbillids (Rodentia, Mammalia) recovered from four Upper Siwalik localities; Moginand (around 3.5-4.5 m.y.), Kanthro (around 2.5 m.y.), Ghaggar (around 2 m.y.) and Nadah (around 1.8-2 m.y.) are described herein. A comparison of Mus linnaeusi sp. nov. reveals its close relationship towards the house mouse Mus musculus. In contradiction to earlier proposals that Golunda migrated to the Indian subcontinent from Africa sometime during Late Pliocene, it is suggested here that Golunda (in the form of Golunda tatroticus sp. nov.) evolved from Parapelomys robertsí of Late Miocene deposits of Siwaliks. Golunda tatroticus sp. nov. exhibits a progressive relationship to the extant Indian Bush Rat Golunda ellioti through Golunda kelleri and Golunda sp. Tatera pinjoricus sp. nov. is considered here to be a link between the extinct Abudhabia kabulense and the extant Tatera indica.

  

The first good skeletal remains of Homogalax protapirinus from the Wasatchian of the Bighorn Basin, Wyoming, indicate that this primitive tapiromorph was more plesiomorphic in many features than primitive equoids including Hyracotherium. Compared to Hyracotherium, Homogalax more closely resembles Phenacodonta (the closest outgroup of Perissodactyla for which postcrania are known) in various details of articular surfaces, muscle attachments, and proportions of the humerus, manus, and pes.Among known taxa, Homogalax most nearly approximates the plesiomorphic postcranial skeletal anatomy of Perissodactyla. 

The reproductive biology of living birds differs dramatically from that of other extant vertebrates. Distinctive features common to most birds include a single ovary and oviduct, production of one egg at daily or greater intervals, incubation by brooding and extensive parental care. The prevalence of male parental care is most exceptional among living amniotes. A variety of hypotheses exist to explain the origin of avian reproduction. Central to these models are proposed transitions from a condition of no care to maternal, paternal or biparental care systems. These evolutionary models incorporate a number of features potentially preservable or inferable from the fossil record (integument, skeletal adaptations for flight, egg and clutch size, nest form, hatchling developmental stage, the number and function of oviducts, and the mode of egg incubation). Increasing availability of data on dinosaur reproduction provides a means of assessing these hypotheses with fossil evidence. We compare dinosaur data to a selection of models that emphasize maternal, paternal or biparental care. Despite some congruence with dinosaur features, no single model on the evolution of avian reproduction conforms fully to the fossil record, and the ancestral parental care system of birds remains ambiguous. Further investigation into dinosaur parental care, nest structures, clutch geometry, egg-pairing, eggshell porosity, and embryo identification may eventually resolve these issues.  

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. 

A systematic analysis of an hipparionine horse assemblage from Maragheh, Iran is made. A brief orientation to systematic philosophy and informal superspecific characterizations of some Old World hipparionines is given as a background to this work. A character state analysis of skulls is made, and has revealed five distinct species. A character state and stratigraphic trend analysis of isolated check tooth and postcranial remains, with known provenance, is also made. These two combined analyses reveal that the most resolute discrimination of hipparionine species and their evolutionary relationships occurs when multiple character complexes of associated skulls, maxillary and mandibular dentitions are made. When this is not possible, skulls have provided the best basis for discriminating species and their evolutionary relationships. Traditional characters of isolated cheek teeth and postcranial remains are shown here to offer limited information content for hipparionine phylogenetic systematics. The systematic portion of this study includes a comprehensive description of cranial and postcranial remains, and has further corroborated the distinction of five species which belong to at least three superspecific groups including: «Hipparion» geltyi sp. nov., Group 1; Hipparion prostylum (s. l.), and Hipparion campbelli sp. nov., Group 3; «Hipparíon» aff. moldavicum and «Hipparion» ?matthewi, Group 2. These species stratigraphic ranges and evolutionary relationships are also given here and argued to be important for establishing future hipparionine geochronologic correlations between a number of Eurasian late Miocene provinces. 

The study of the bovids from Al Jadidah (Hofuf Formation, Saudi Arabia) confirms that the fauna comes from a pre-Hipparion level. The Al Jadidah age is close to that of Fort Ternan (14 m.y.) and Beni Mellal, but cannot be older than that of Fort Ternan. The age of the Hofuf Formation is close to but slightly older than the oldest deposits of the Ngorora Formation (Kenya). 7 to 9 species have been recorded, of which 2 to 4 remain indeterminate. If the great specific diversity of te bovids from this locality gives evidence of immigrations from anterior Asia (Turkey) (e.g. Pachytragus Iigabuei sp. nov.), the bovid assemblage of Al Jadidah results in fact from a double influence: from the anterior Asia and mainly from Africa (e.g. the Caprotragoides lineage and the Neotragini? Homoiodorcas). The Al Jadidah bovids reflect, on the whole, the predominant character of open to very open environment, which supports the conclusions drawn from our two preliminary studies. 

A skull of Parabos cordieri, undamaged by fossilisation, allows us to make an endocranial cast, which is compared to those of Bos taurus, Boselaphus tragocamelus and Hippotragus equinus. These are studied by general form (shape, volume, « rolling-up›› and inclination), and by detailed morphology (gyri and sulci patterns, rete mirabile, importance of rhinencephalon and cerebellum).
A preliminary study is made in order to recognize convolution topography, gyri, sulci, and the various encephalic regions as clearly on an endocranial cast as on a bare encephalon; an intermediate stage is the study of an encephalon covered with «soft» meninges.
The comparative study reveals great similarity between the endocranial cast of Parabos cordieri and that of Boselaphus tragocamelus, both belonging to the tribe Boselaphini. On the other hand, a marked differences separates the cast of Parabos cordieri from that of Bos taurus, representing the tribe Bovini to which Parabos cordieri had been referred. The endocranial cast of Hippotragus equinus, which had long been considered the descendant of Parabos cordieri, is also quite different from that of Parabos. 

A new Devonian vertebrste locality has been discovered in 1976 in the basal part of the Khush-Yeilagh Formation in the eastern Alborz Mountains of Iran. The fossils occur in a band one centimeter thick which is identifiable at other outcrops in the area. A preliminary study of the remains has yielded the following faunal list : Placodermata (Phlyctaeniida indet.. Groenlandaspididae indet.. Coccosteidae indet., Holonema sp., Ptyctodontida indet., Antiarcha indet., Bothriolepis cf. kwangtungensis), Elasmobranchii (Ctenacanthidae indet.), Acanthodii (Gyracanthus sp., « Onchus » overathensis, Ischnacanthiforme indet.), Dipnoi (? Dipteridae indet.), « Crossopterygii ›› (Onychodus cf. sigmoides, Holoptychiidae indet., Osteolepididae indet.). This fauna is older than the Middle Givetian and probably of Middle or Lower Eifelian age. Owing to its diversity, it may prove possible to use it in the future as a reference fauna for the study of the Devonian vertebrates in Central Asia and the Middle East.