Simpson (1937a) reconstructed the brain of the Paleocene multituberculate Ptilodus as having the olfactory bulbs widest anteriorly, an unusual condition among mammals. Slight preparation and reexamination of the endocast specimens of Ptilodus reveals that the olfactory bulbs in fact taper anteriorly, as in the recently-described endocranial casts of three multituberculate species from the Late Cretaceous of Asia, and as in those of other mammals. The brain of Ptilodus was therefore essentially of the same general pattem as in other multituberculates. Ptilodus differs, however, in having the vermis more deeply inserted between the cerebral hemispheres. Other details concerning the endocast morphology of Ptilodus are clarified.

The encephalization quotient (EQ) of Ptilodus is recalculated from revised estimates of both endocranial volume and body mass to fall somewhere within a broad range of values; from 0.41 to 0.62 if the olfactory bulbs are included and from 0.37 to 0.55 if they are not. In any case, the relative brain size of Ptilodus is roughly equivalent to that of Chulsanbaatar, the only other multituberculate for which EQ has been calculated, but considerably smaller than that of an average extant mammnal. 

We report the discovery of amniotic eggshells and theropod teeth from the Late Cretaccous  period in Morocco.The megaloolithid family represents the only known dinosaur egg remains in the north part of Africa and attests indirectly to the occurrence of sauropod dinosaurs (titanosaurids) in the Maastrichtian of Africa.

  

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 litoptem Proterotheriidae are extinct endemic South American ungulates frequently used as an example of evolutionary convergence with the horses. They were considered to be exclusively Tertiary representatives with the youngest record being in the late Pliocene, before the appearence of the equids and cervids during the Great American Interchange. Two undoubted Pleistocene records in Argentina and the specimen here described from Uruguay, confirm the persistence of the proterotherids into that period. In the Quaternary, these ungulates are found outside the typical pampean region and probably were confined to a few northern and warmer more forested relictual microhabitats.

  

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. 

Two new finds of pantodont materials from southern China, assigned to Archaeolambda, are described in this paper. One, a new species from the Nanxiong Basin, Guangdong Province, is similar to Alcidedorbignya inopinata from the early Paleocene of Tiupampa, Bolivia in size. It provides reliable evidence of the occurrence of Archaeolambda in the early-middle Paleocene of southern China. The second find includes specimens of Archaeolambda sp. cf. A. planicanina from the ?late Paleocene of Hengyang Basin, Hunan Province, which are the first record of a fossil mammal from the area near Hengyang city. The only vertebrate fossils previously found here were two genera of crocodiles discovered in 1938. This find sheds new light on the local biostratigraphy. 

The genus Parasteiromys AMEGHINO, 1904 is revalidated, and P. friantae sp. nov. (Hystricognathi, Erethizontidae) from Colhuehuapian (early Miocene) sediments of the southern cliff of Colhue-Huapi Lake (Province of Chubut, Argentina), is described. The molar morphology of these taxa and of living porcupines adds new elements to understand the dental evolution of the Erethizontidae, and to propose the hypothetical ancestral molar pattern for this family. This pattern does not correspond to any of the morphologies traditionally proposed as ancestral for South American hystricognathous rodents. The proposed pattern is characterized by a metaloph disconnected from the posteroloph and oriented towards the hypocone, and the third loph incompletely developed with the lingual portion homologous to the mesolophule of Baluchimyinae (Chapattimyidae) from the Miocene of Pakistan. The inferred steps of the molar evolution of erethizontids towards the pentalophodont condition, considered derived for the family, are illustrated. This study strengthens the hypothesis placing erethizontids in a basal position among rodents of the suborder Hystricognathi.

  

Recent collecting of fossil vertebrate remains from the lowermost member of the Aquia Formation (Paleocene), has enabled me to report here for the very fIrst time, the earliest occurrence for the teeth of Palaeocarcharodon in the fossil record of the New World.
This report represents only one species of neoselachian from this locality, the remaining fauna of which will subsequently be described. 

A large avian femur recently discovered at the Late Cretaceous Montplo-Nord locality at Cruzy (Hérault, southern France) is referred to the giant bird Gargantuavis philoinos. The estimated mass of the bird is 57 kg, within the range of living cassowaries. The specimen provides new evidence about the anatomy of G. philoinos, notably showing that the distal end of the femur was similar to that of modern birds in having a condylus lateralis subdivided into two semicondyles. A new diagnosis of Gargantuavis philoinos is provided and the taxon is placed in a new family of basal ornithurines.
  

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. 

xx 

In dilambdodont molars the primitive crest between paracone and metacone (centrocrista) is represented by a pair of crests that join the mesostyle (postparacrista, premetacrista). The cutting action of these crests against the crests of the hypoconid is described. Dilambdodonty is a derived adaptation for greater cutting efficiency. It has evolved several times and in more than one way. 

Anthracotheres from the Pondaung Formation, Myanmar, are considered as one of the most primitive artiodactyl groups and they represent the oldest known record in the world. Thus, the understanding of this group has numerous implications for evolutionary biology and biochronological correlations. However, the systematlcs of these mammals has been interpreted in different ways, and the main debate focuses on the number of taxa represented in the Pondaung Formation. The revised taxonomy proposed here is mainly based on the relative development of the upper molar W-shaped ectoloph, system of crests and stylar cusps, and on body size. On the basis of these characters, they are classified into four genera including six different species. Two well-known genera, Anthracotherium and Anthracokeryx, are validated and more precisely diagnosed. Anthracokeryx possesses a better developed W-shaped ectoloph, system of crests and stylar cusps than Anthracotherium, which displays notable differences with the more derived representatives of this genus. Both of these Pondaung genera show evidence for sexual dimorphism. However, the incompleteness of fossil material fueled a debate concerning the status of two additional Pondaung anthracotheres, Siamotherium and Anthracohyus. The latter genus is of uncertain affinities, but it has been considered as a hippopotamid ancestor. Despite new material attributed to these two forms, additional discoveries are still required to establish their taxonomic status. The hypothesis that Southeast Asia was the centre of origin of Anthracotheriidae is supported by the retention of numerous primitive dental characters in these taxa and by the antiquity of the Pondaung Formation, to which an age of 37 My is now generally accepted. 

The East African Miocene Macroscelidea, lnsectivora and Chiroptera are revised on the basis of new material. New taxa proposed are: Miorhynchocyon, .n. gen. (Macroscelididae): Míorhynchocyon meswae, n. sp.: Pronasílío ternanensis. n. gen.. n. sp. (Macroscelididae); Hiwegicyon juvenalis, n. gen. n. sp. (Macroscelididae); Parageogale, n. gen. (Tenrecidae): Prochrysochlorinae, n. subfam. (Chrysochloridae): Propottininae, n. subfam, (Pteropodidae); Chamtwaria pickfordi, n. gen., n. sp. (Vespertilionidae). Gymnurechnínus songhorensis is synonymised with G. camptolophus. The new material provides additional information on the dentition, especially of Myohyrax oswaldi. Galerix africanus. Amphechínus rusingensis, Protenrec tricuspis and Parageogale aletris. Partial skulls are described of Amphechinus rusingensis, Protenrec tricuspis, Prochrysochloris míocaenicus and Taphozous incognita. The oldest member of the Macroscelidinae (Pronasilio) is described from Fort Ternan. Galerix africanus is closely related to G. exilis from Europe. Amphechinus rusingenesis is compared with Asiatic Oligocene Erinaceinae. The Miocene age of Crocidura is rejected. On the evidence of humeri, the following families of Chiroptera are newly reported: Pteropodidae, Nycterididae, Vespertilionidae, Molossidae. Propotto is regarded as an offshoot from the Pteropodidae, not ancestral to modern forms. Chamtwaria is a primitive vespertilionoid, provisionally placed in the Kerivoulinae. Erinaceidae probably entered Africa at the beginning of the Miocene, before 20 Ma. Faunistic differences between deposits are largely to be ascribed to differences in local environment. 

A comparative bone histological study of the three known genera of the endemic European ornithopod dinosaur family, Rhabdodontidae, is presented here in an ontogenetic context. Investigated specimens were assigned to different ontogenetic stages based exclusively on the histological indicators of osteologic maturation during diametrical bone growth; an entirely size-independent method as opposed to most previous studies. Qualitative comparison of bone histology of corresponding ontogenetic stages and elements among the three valid rhabdodontid genera, Mochlodon, Zalmoxes, and Rhabdodon, revealed some consistent patterns. Genus specific histological differences within Rhabdodontidae are most expressed between Rhabdodon and the Mochlodon-Zalmoxes clade. These indicate a prolonged phase of fast growth and a less constrained cyclicity in the growth dynamics of Rhabdodon, as opposed to the slower and more regulated growth strategy reflected in the bones of Mochlodon and Zalmoxes. These genus specific differences are consistent with the phylogenetic interrelation of the genera and are most probably related to the pronounced differences in body size. However, when compared to other ornithopods, most detected histological features in rhabdodontids do not seem to reliably reflect either phylogenetic relations or body size. A notable common feature of all rhabdodontid genera irrespective of body size is the ontogenetically early onset of cyclical growth and secondary remodelling; a pattern that more resembles the condition found in derived ornithopods than that described in more basal taxa which are closer relatives of rhabdodontids. The recognition of taxon-specific histological patterns as well as patterns indicative of ecological and thereby functional traits clearly requires more accurate, preferably quantitative evaluations.   

The dentition of Welcommia bodeuri nov. gen. nov. sp. from the Valanginian of Southem France is described and reconstructed. Species and genera of Upper Jurassic and Lower Cretaceous Hexanchiformes are reviewed and discussed.
The genus Notidanoides MAISEY, 1986 must be restricted to the single Nusplingen Upper Jurassic specimen, whose attribution to the species muensteri AGASSIZ, 1843 remains doubtful.
The genus Paranotidanus WARD &THIES, 1987 that does not rest on any type-species nor on any precise dental characterization must be rejected.
The genus Eonotidanus PFEIL, 1983, based on a very poorly preserved and heterogeneous type-material must also be rejected.
Teeth from the Lower Cretaceous, with a peculiar morphology, previously assigned to Eonotidanus or to Notidanoides, are to be ranked in the new genus Pachyhexanchus. 

Sirenians are among the common marine fossil remains found in the Faluns deposits of western France. We describe new material of a Dugongidae sirenian from the middle Miocene Savignean facies of La Morfassière quarry (Indre-et-Loire, northwestern France) that includes a well preserved and almost complete skull associated with its mandible, several vertebrae and ribs. The cranial remains exhibit features that allow to attribute them to Metaxytherium medium, a species recorded from the middle and early late Miocene of European and Mediterranean coasts. The discovery of an associated skull and mandible of this species is unusual in this area and deserves to be reported, mostly because its preservation contributes to a better knowledge of the variable structure of its skull and teeth anatomy. For the first time the body size and weight of M. medium can be assessed through regression equations based on skull measurements. The particularly good condition of the material can be explained by the calm and deep marine environment in which it was deposited.
  

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. 

A fragmentary mandible and maxilla of a small sized Agriotherium of a young individual discovered from a Pliocene fissure filling in Xiaoxian county (Anhuei Province, China) are described. Judging from the morphology of the dentition and its dimensions the new material can be identified as Agriotherium inlermedium (STACH l957). Hendey's proposition (1980) that the Agriotherium species are derived from Indarctos is reconsídered on the basis of the new documents. As a result of a more general phylogenetic discussion it can be stated, that: 1. the supposed size increase as well as other trends, leading from Indarctos to Agriotherium are untenable ; 2. there are no positive indications to assume a phylogenetic transition of these two genera. 3. there are no real arguments in favor of an adaptational reversal in the evolution of Agriotherium. Hence, many features of that genus supposed by Hendey to be derived are plesiomorphic ; 4. regardless of the previous points it is methodologícally impossible to establish direct ancestor - descendant relationships between Indarctos and Agriotherium species, as Hendey did. Based on the data available and especially on the characters of the new material from China it is more likely that Agriotherium and Indarctos are two genera which developed independently. While advanced Agriotherium species, e.g. A. africanum, resemble in some respects Indarctos by adaptational analogies, more primitive species, e.g. Agriotherium intermedium, are quite dissimilar to lndarctos. While Indarctos might be derived from an Ursavus like forerunner, Agriotherium has its roots more likely somewhere in between Ursavus and the Hemicyon-group. 

The fauna studied in the following work involves the dentitions and skulls more or less complete of 5 genera, among which only Cephalomys was previously known by its skull. One must notice that the Salla's species of this genus is a new one. Sallamys, rather small, shows a dentition rather similar to that of Platypittamys Wood from Patagonia. The upper molars, more primitive than those of this last genus, according to the smaller dimensions of the hypocone, retain a distinct metaloph. This metaloph tends to be reduced in a way which may give us a possibility to understand how it disappeared in Platypittamys. The upper P4 can be compared as well to that of Platypittamys as to that of Gaudeamus from the African Oligocene. The lower P4, more molarized than that of Platypittamys, is already moving towards the miocene type of structure. The infraorbital foramen is wide and the insertion of the masseter on the muzzle is spacious. Branisamys, genus of a great size, shows an auditory region partly preserved, peculiarly the promontorium with the fenestra rotunda, entirely of the Hystricognathi type. Upper molars are very clearly pentalophodont. A new reconstruction is proposed for the tooth called Villarroelomys by Hartenberger. This tooth is shown to be a lower D4, perhaps of Branisamys , certainly of a rather nearly allied form, and Hartenberger does agree with the essential part of this new conclusion. Of Incamys, two incomplete skulls are known, each one being admitted to be the type of a distinct species, the first one being I. bolivianus, I. pretiosus the second. The infraorbital foramen is of a great size and the impression of the masseter on the muzzle is spacious. The sphenopalatine foramen is widely developed and of a really very uncommon great size. Only Thryonomys from Africa shows a similar tendency to the enlargement of this foramen, but not so extreme. The main basicranial foramina can be observed. The upper teeth, hemi-hypsodont, show, either a vestigial metaloph, similar to that of recent Thryonomys from Africa, associated with a well developed mesoloph, either a well developed metaloph, while the mesoloph is reduced or absent. Cephalomys was previously known by anterior parts of the skull showing a wide infraorbital foramen and a spacious facial insertion of the masseter. Its lacrymal is of the phiomorph type and the spheno-palatine foramen is seemingly of great size, like in Incamys. The species is new. The varied peculiarities of the upper teeth of these genera can be easily understood if we refer to the plan of the teeth of Phiomys andrewsi from the Oligocene and Miocene of Africa. The structure of this genus, clearly more primitive, still typically brachyodont, shows and clearly explains the fundamental coherence of the varied realisations arised from such a structure. Luribayomys n.g. is known only by an anterior half of a skull without teeth. It is remarquable by the great development of the masseter's insertions on the muzzle and by the lacrymal region, well preserved, typically phiomorphid. The classification previously published by A.E. Wood and B. Patterson is granted in its essential parts, provisionally, but not as a definitive solution. Nevertheless the Dasyproctidae are integrated within the Cavioidea, following the conclusions of Bugge and of Vucetich, reached independently. The conclusion emphasizes the exceptional meaning of the fauna of Salla-Luribay. This shows that Platypittamys, while interesting, can no more be supposed certainly representative of the normal structure of the Oligocene Caviomorph, and not even of their ancestors. The anatomical peculiarities exhibited in these new samples, auditory region, lacrymal, spheno-palatine foramen, reinforce the primitive structural identity with the Phiomorpha. Similarly, the new lower D4 favour very close relationships, ever if the affinities of the D4 has been questioned or minimized by Wood and Patterson. It is certainly possible to admit that parallelism could explain limited similarities, like the presence in North America of Rodents with an hystricomorph type of infraorbital foramen and an hystricognath mandible. But if the parallelism could be a sufficient explanation of the identical association of multiple and complete structures observed in the Caviomorpha and Phiomorpha, all the Zoological systematic would have to be questioned. The last positions of A.E. Wood on the subject (1975) are revised and criticised, and the recent publications studying the problems of distance between Africa and South America in Eocene time, as a consequence of the drift, are quoted; the possibility of transportation by rafts is shown. A new hypothesis is proposed about the interrelationships of Pentalophodont Rodents, with interesting paleobiogeographic implications.