The discovery of new hippopotamid material from the late Miocene Baynunah Formation (Abu Dhabi, United Arab Emirates) has prompted the revision of the existing material of this as yet unnamed fossil taxon. The Baynunah hippopotamid appears to be distinct from all other contemporary and later species in having a relatively more elongate symphysis, a feature similar to the earlier (and more primitive) Kenyapotamus. Yet, the Baynunah hippopotamid presents a dentition typical of the Hippopotaminae. It is therefore a distinct species attributed to the later subfamily, described and named in this contribution. This species provides further evidence for a ca. 8 Ma evolutionary event (termed “Hippopotamine Event”) that initiated the spread and ecological significance of the Hippopotaminae into wet habitats across Africa and Eurasia. The morphological affinities of the new species from Abu Dhabi suggest that the Arabian Peninsula was not a dispersal route from Africa toward southern Asia for the Hippopotamidae at ca. 7.5 Ma to 6.5 Ma. 

Two steps can be distinguished in the history of the first invasion of western and south western Europe by the arvicolines. The first step corresponds to the installation of these rodents with the immigration of Promimonys inxuliferus Kowalski, then of Mimomys stehlini Kormos and of Mimomys gracilis (Kretzoi). The second is characterized by the establishment of a geographic differentiation in the arvicoline fauna between the south of France and Spain, from where are described new species of Mimomys (Mimamys cappettai, Mimomys septimanus, Mimonys medasensis), and the rest of France, where are found only elements already known from central Europe or England (Mimomys polonicus Kowalski, Mimomys pliocaenicus F. Major, Mimomys reidi Hinton, or forms very close to the latter). This geographic differentiation, which is very certainly the consequence of the division of Europe into distinct climatic provinces, one of them being the southern province comprising at least Spain and southern France, could result from a cladogenetic evolution of Mimomys stehlini and Mimomys gracilis after their immigration. The present work is also a contribution to the search for correlations between the diverse micromammal localities of the latest Pliocene (or early Villafranchian) and of the early Quaternary of 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. 

The earliest cetaceans are found in the early Eocene of Indo-Pakistan. By the late middle to late Eocene, the group colonized most oceans of the planet. This late Eocene worldwide distribution clearly indicates that their dispersal took place during the middle Eocene (Lutetian). We report here the first discovery of a protocetid fossil from middle Eocene deposits of Senegal (West Africa). The Lutetian cetacean specimen from Senegal is a partial left innominate. Its overall form and proportions, particularly the well-formed lunate surface with a deep and narrow acetabular notch, and the complete absence of pachyostosis and osteosclerosis, mark it as a probable middle Eocene protocetid cetacean. Its size corresponds to the newly described Togocetus traversei from the Lutetian deposits of Togo. However, no innominate is known for the Togolese protocetid, which precludes any direct comparison between the two West African sites. The Senegalese innominate documents a new early occurrence of this marine group in West Africa and supports an early dispersal of these aquatic mammals by the middle Eocene.
  

Previous chronological arrangements of South American Quaternary land mammal faunas are appraised on the basis of current geological and paleontological data. Three South American late Pliocene-Pleistocene land mammal ages are conventionally recognized, from oldest to youngest, the Uquian, Ensenadan, and Lujanian ; all are defined on Argentine faunas.

     The Uquian is based fundamentally and historically on the fauna from the Uquía Formation in Jujuy Province, northwestern Argentina. Important known formations in Argentina yielding Uquian Age faunas include the sub-surface Puelche Formation (or Puelchense) near the city of Buenos Aires, and the Barranca de Los Lobos and Vorohué Formations between Mar del Plata and Miramar, Buenos Aires Province. A tentative subdivision is propos-ed for the Uquian into three subages based on knowledge of the Mar del Plata-Miramar sequence, from oldest to youngest, the Barrancalobian, Vorohuean, and Sanandresian. In Argentina the Uquian is presently marked by the first known record of Scelidodon, Hydrochoeropsis, Ctenomys, Canidae, Ursidae, Gomphotheriidae, Equidae, Tapiridae, Camelidae, Cervidae, and the last known record of Thylatheridium, Thylophorops, Dankomys, Eumysops, Pithanotomys, Eucoelophorus, Hegetotheriidae, Sparassocynidae, and Microtragulidae.

The Ensenadan Age is based on the fauna from the Ensenada Formation near the city of Ensenada, Buenos Aires Province. In Argentina the Ensenadan is marked by the first known record of Lomaphorus, Neothoracophorus, Plaxhaplous, Cavia, Lyncodon, Lutra, Galera, Smilodon, Dicotyles, Lama, Vicugna, the last known record of Orthomyctera, and the only known record of Brachynasua.

     Typícal beds of late Lujanian Age in Argentina consist of fluvial deposits occupying stream channels, and shallow basins, often incised into beds of early Lujanian (i.e. Bonaerian of early workers) and Ensenadan Age. The Lujanian Age is based on a fauna from beds along the Rio Luján, about 65 km west of the city of Buenos Aires, Buenos Aires Province. The Lujanian in Argentina is marked by the first record of Equus, Chlamyphorus, and Holochilus, and the last record of Megatherioidea, Glyptodontoidea, Arctodus (=Arctotherium), Smilodon, Litopterna, Notoungulata, Proboscidea, Equidae, Morenelaphus, and Palaeolama.

   These land mammal ages are often difficult to recognize in other South American countries. The compositions of South American Pleistocene faunas vary with the environment. Some taxa were widely distributed in fossil deposits throughout the continent, but their occurrences need not reflect synchroneity. This is a result of changing climates and habitats in time. Consequently, proposed intracontinental correlations need confirmation based on magnetostratigraphy and a radioisotope time scale. Paleontologic characterizations of these land mammal ages (i.e. first and last record, and guide fossils) are useful for much of Argentina, but extensions to most of the other parts of South America are at best tenuous.

The majority of known non-Argentine Pleistocene faunas are believed to be Lujanian in age. Possible non Argentine early Pleistocene (Uquian) faunas include Ayo Ayo and Anzaldo in Bolivia, and Cocha Verde in southern Columbia. A possible middle Pleistocene (Ensenadan or early Lujanian) fauna is the Chichense of Ecuador. Paleomagnetic and radioisotopic date (MacFadden et al., 1983) clearly indicate that the greater part of the Tarija fauna (Bolivia) is Ensenadan in age.

  The end of the Pleistocene and beginning of the Holocene in South America is marked by extinction of nearly all large mammalian herbivores and their specialized large predators. Radiocarbon age determinations suggest that large scale extinctions of megafauna occurred between 15,000 and 8,000 yrs. B.P. (years before present). 

The Tafna Basin corresponds to the lowlands, which are located in front of Tessala and Traras ranges, below the Tlemcen mountains, Algeria. This basin displays a complete sedimentary cycle dominated by lagoonal-fluvial and marine deposits. The continental formations located at the base of these deposits are mainly composed of alternating sandstones and clays. An early late Miocene age has been previously attributed to them, based on direct correlations with marine deposits. Search for micromammal fossils led to the discovery of three different rodent species from a single level of the Djebel Guetaf section, located at the bottom of these deposits. The rodent assemblage indicates a late Miocene age. Combined magnetostratigraphical and biostratigraphical investigations were carried out to provide a more accurate age control of these continental deposits. Sixty-four oriented rock samples were collected for a magnetostratigraphic study along a 92 meters thick section including the fossiliferous layer. Rock magnetic investigations indicate the presence of both high and low coercivity minerals. Specimens subjected to progressive thermal demagnetization procedures show that the samples exhibit a high temperature magnetization component and display a normal polarity. Based on biostratigraphic constraints, the Guetaf section is correlated with Chron C4An, indicating an age ranging from
9.1 to 8.7 Myr.
  

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. 

The investigations undertaken at Crivadia (Hateg Depression, Hunedoara District, Romania), the type locality of Crivadiatherium mackennai RADULESCO el al. (Radulesco, Iliesco et lliesco, 1976), led to the discovery of remains of a new Embrithopod. Close to the above mentioned species, but larger in size, this animal is here described as a new species of Crivadiatherium, C. iliescui. ln addition, the comparison made between the forms indicated above and Palaeaamasía kansui OZANSOY from the Eocene deposits of Anatolia (Ozansoy, 1966; Sen et Heintz, 1979) showed that the latter species included a heterogeneous material; this permitted us to distinguish the form in the Anatolian locality Ciçekdag-Arabin Kôyü under the name Palaeoamasia sp. The geographical distribution and diversity of the Embrithopod species under discussion (Balkan, Anatolia) support the idea of an eurasiatic origin of this group and seem to suggest the existence during the Eocene of a particular faunal province in south-eastern Europe. 

Near "la Lieude", in the Lodève basin, more than a thousand of footprints are distributed in a twenty of trackways which amounts to 220 m length. They have been found on calcareous siltstone level in the B site named also "Réserve Naturelle Volontaire". This last is located in the Saxonian summit dated Upper Permian. "La Lieude" tracks are described by using statistical methods then they are compared with others from the world Permian. What allows to distinguish 4 following ichnotaxa: Lunaepes ollierorum nov.ichnosp., Merifontichnus thalerius nov. ichnogen. and nov. ichnosp., Planipes brachydactylus nov.ichnosp. and Brontopus circagiganteus nov. ichnosp. All these traces are attributed with possibility or probability to Therapsida or to Therosauria, except Brontopus circagiganteus nov. ichnosp. that could be due to Caseamorpha. All these animals whose sizes have been estimated between l and 5 m lived probably in a playa environment.The biological and sedimentological data from "la Lieude" footprints levels compared with informations provided by the tracks orientations, suggest the following scenario. Animals coming from the North have crossed a sandy channel bank with plants zones by directing to the South for the majority. Maybe, they were going to the lacustrine part of the playa, close to "la Lieude" footprints that they have just trampled on. 

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. 

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. 

The present study of Artiodactyla from the Middle Eocene of the Geiseltal lignite beds concems systematics, biostratigraphy, and palaeoecology on the basis of 174 specimens: isolated remains to more complete skeletons. Instead of the formerly known five species of two families are now recognized 14 species of the Diacodexeidae, Dichobunidae, Cebochoeridae, and Haplobunodontidae. New species are Aumelasia maniai, Anthracobunodon neumarkensis, Masillabune franzeni. Four species of the Geiseltalfauna are definitely known from elswere, and five species are closely related to those from other European localities. Evidently the faunal situation of artiodactyls during the Middle Eocene of Europe was largely uniform. The distribution of artiodactyls within the sequence of the Geiseltal strata corroborates the biostratigraphical concept of the land mammal age Geiseltalian (Franzen & Haubold l986b) as well as the mammalian reference levels MP 11-13 (Franzen 1987). Reconstructions of the skulls and skeletons allow conclusions on the functional morphology and palaeoecology of the artiodactyls of the European Middle Eocene 

Pleistocene bird fossils have been studied from nine localities on Crete. Part of this material was described earlier by the author (Weesie, 1982) and will not be treated here in extenso, the results will be incorporated. More than one third of the over 10,000 fossil bird bones available could be identified ; they were found to represent at least 65 bird species. The following species of the Pleistocene Cretan avifauna are new to the fauna of Crete : Branta ruficollis, Haliaeetus albicilla, Gyps melitensis, Aquila chrysaetos simurgh n. ssp., Ketupa zeylomensis, Aegolius funereus, Dendrocopos leucotos, Zoothera dauma, Turdus iliacus and Pyrrhula pyrrhula. The Pleistocene Cretan avifauna differs less from comparable mainland avifaunas than (fossil) avifaunas from oceanic islands do. Still, the Pleistocene Cretan avifauna has two qualities that are characteristic of island avifaunas : the almost complete absence of a group of birds (the Galliformes) and the presence of two endemic (sub)species : the giant eagle Aquila chrysaetos simurgh n. ssp. and the long-legged owl Athene cretensis (Weesie, 1982). The new subspecies is described in the present study.
These endemic birds of prey were found in association with their supposedly principal prey species (now extinct as well) : endemic mice for the owl and endemic deer for the eagle. Endemic mammals have been found in association with endemic birds of prey on many islands, not only in the Mediterranean. There is evidence that the size of endemic birds of prey becomes optimally adapted to their feeding on certain endemic mammals, especially rodents. Another characteristic of the Pleistocene Cretan avifauna is the great number of species of birds of prey. This appears to be a common characteristic of fossil avifaunas from caves on Mediterranean islands as well as from caves on the European mainland. However, we think that ecological conditions on Pleistocene Crete (especially the abundant presence of mice) helped to account for the high representation of birds of prey. Furthemore, the fossil avifauna enables us to draw some conclusions about the climate and vegetation on Pleistocene Crete : it is concluded that the climate was cooler than today and that Crete was largely covered with forests. Finally, the reasons for the extinction or disappearance from Crete of some bird species of the Pleistocene Cretan avifauna are discussed. 

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).



  

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 principles and practices employed in establishment and recognition of South American land mammal ages are reviewed along with previous and present concepts of distinguishing time, rock, and faunal units. Previous chronological arrangements of South American Tertiary land mammal faunas are appraised on the basis of recent geological and paleontological data. Twelve South American Tertiary land mammal ages are here recognized [from oldest to youngest, Riochican (middle to late Paleocene); Casamayoran (early Eocene); Mustersan (middle Eocene); Divisaderan (late Eocene); Deseadan (early [to middle?] Oligocene); Colhuehuapian (late Oligocene); Santacrucian (early Miocene); Friasan (middle Miocene); Chasicoan (late Miocene); Huayquerian (latest Miocene); Montehermosan (early to middle Pliocene); and Chapadmalalan (late Pliocene)]. As all except the Friasian were originally defined on the basis of Argentine faunas, these are discussed first and at length, and each is reviewed with discussion of type locality, stratigraphy, type fauna, and faunal correlations. Non-Argentine faunas are then discussed country by country in alphabetical order.

     A review is given of radioisotope dates obtained on volcanic rocks (i.e., basalts, tuffs) associated with mammalbearing beds in Argentina. Based on these age determinations and on correlation of the late Tertiary land mammals involved in the interchange between North and South America, a chronology of South American land mammal ages correlated with North American land mammal ages and European marine stages is proposed.

It is concluded that South America was an island continent through most of the Tertiary Period (ca 65 to about 3 Ma). As a result, the land mammal fauna of South America developed in isolation and was dominated by autochthonous endemic groups. Toward the end of the Tertiary (i.e., middle Miocene) a unique faunal balance had been achieved by the descendants of the ancient inhabitants (notoungulates, litopterns, condylarths, astrapotheres, edentates, marsupials) and of later (late Eocene) waif immigrants (caviomorph rodents, platyrrhine primates). A prominent feature of this mammal fauna was the combination of carnivorous and omnivorous marsupials with native placental herbivorous ungulates, subungulates, and edentates.

Sometime during the late Miocene, a limited but important interchange of mammalian taxa between North and South America took place. Procyonids (raccoons and their allies), a group of North American origin, first appear in South America in strata of Huayquerian Age, while members of the extinct South American ground sloth families Megalonychidae and Mylodontidae first appear in North America in early Hemphillian time. These groups dispersed along island arcs before the appearance of the Panamanian land bridge in the Pliocene (ca 3.0 Ma). Cricetine rodents, a group of North American origin, are first known in South America in strata of Montehermosan Age. The known taxa are too advanced and diversified to be considered the first of this group to invade South America. lt is believed by some workers that these rodents arrived before the Montehermosan, possibly in the late Miocene or earlier, by waif dispersal from North America.

The isolation of South America ended with the appearance of the Panamanian land bridge, which provided a direct, dry land connection between the two Americas. Across this portal an extensive interchange of terrestrial faunas occurred, and the fossil record documents an intermingling of these long-separated land mammals faunas.

      The beginning of this interchange by land route in South America is marked by the appearance of mammals which evolved from North American emigrants in the Chapadmalal Formation of Argentina. These include a mustelid (Conepatus), a tayassuid (Argyrohyus), and four genera (Akodon, Dankomys, Graomys, Reithrodon) of cricetine rodents. The appearance of this contingent of northern animals favors the existence of the Panamanian land bridge by this time. Likewise, a large number of terrestrial vertebrates of South American origin appear in North America in beds of late Blancan Age date around 2.7 Ma. Among the mammals are Neochoerus, Erethizon, Glyptotherium, Glossotherium, Kraglievichia, and Dasypus. 

The artiodactyls (Mammalia) from the latest Ypresian locality of Prémontré from the Paris Basin (niveau repère MP 10 in the lower Eocene of the Paris Basin) are described in this paper. Three species have been identified: 1) Diacodexis cf. varleti SUDRE et al., 1983; 2) a new species of Eurodexis ERFURT & SUDRE (E. russelli nov. sp.) defined after the revision of the species Messelobunodon? ceciliensis from the Lutetian beds of Geiseltal (Germany); and 3) Eurodexeinae indet., a probable ancestor of another form from the Geiseltal which was previously recorded as Homacodon? sp. (Erfurt 1993) and now named Parahexacodus germanicus. The two later forms are referred to the new subfamily Eurodexeinae (Erfurt & Sudre 1996). The analysis of these forms as weIl as comparative studies have led us to reconsider our previous conclusions regarding the content of the species Protodichobune oweni LEMOINE 1878 and some aspects of Ypresian diacodexid evolution. One can postulate that the divergence of E. russelli nov. sp. occurred during the first radiation of these primitive artiodactyls. Some other stem form with bunodont teeth such as Protodichobune and Aumelasia have also differentiated from Diacodexis. Like Eurodexis, these two genera persist during the middle Eocene. The absence of Protodichobune and Aumelasia at Prémontré is probably due to particular ecological conditions. 

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. 

The genus Pachynolophus, one of the poorest known of the Palaeotheriidae, includes the brachyodont forms with reduced and non-molariform premolars and with upper molars lacking a mesostyle. Quantitative characters (divers surface indications and elongation of the teeth), while demonstrating a close relationship to Hyracotherium, permit a better differentiation of the genus, confirm its specific splitting, and permit the distinction of three lineages. The skull from Memerlein is taken as the type of a new species, P. Iavocati, of which the dentition is extremely characterized by its lophiodonty, the strong reduction of the premolars and the reduction of the cingula. This characterization testifies to a late age which extends the existence of the genus quite near to the Eocene-Oligocene limit. Compared with the only two skulls known of related species (Hyracotheríum vulpiceps and Pachynolophus Iivinierensis), that from Memerlein is distinguished by progressive characters affecting diferent regions but most particularly the braincase; it is not possible, however, to isolate within this evolution the part which leads to a systematic differentiation. Modernization is translated by a considerable increase in size of the braincase, principally in the frontal region, a development of the facial region with anterior displacement of the dental series and a greater specialization of the masticatory apparatus. This evolution parallels the history of the Equidae of the North American early Tertiary, but certain particularities, the form of the alisphenoid, the presence of an anterior frontal foramen, and the structure of the paroccipital apophysis, testifies to the independance of the European forms. 

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.