Etude sur les vertébrés inférieurs (VIIe Symposium International, Parc de Miguasha, Québec, 9-22 Juin 1991), édité par Marius ARSENAULT, Hervé LELlÈVRE & Philippe JANVIER, 1994. Bulletin du Muséum National d'Histoire Naturelle, Paris, 4e Série, T. 17, Section C, n° 1-4, 529 p.

Ce volume spécial du Bulletin du Muséum réunit les actes du congrès international sur les Vertébrés inférieurs qui s'est tenu au Québec en 1991. 

The mammalian fauna (represented only by isolated teeth) from the early Cretaceous of Morocco includes a number of non-'therian' specimens, characterized by the antero-posterior alignement of the main molar cusps. This assemblage is very heterogenous, including forms (among them Gobiconodon palaios sp. nov.) that can be related to Laurasian triconodonts and several forms so far known only in this part of Gondwana (among them Kryptotherium polysphenos gen. et sp. nov.). The latter, in particular, exemplifies the diversity of the mammalian dental morphology in the Mesozoic, often largely underestimated. In the last part of this paper, the 'therian' affinity of the 'amphilestids' is discussed, on the basis of the arrangement of molar cusps, the interlocking mechanism and the occlusal pattem. 

Avec ce volume se clôture l'étude géologique et paléontologique des sites à hominidés de Koobi Fora. Il fait suite aux deux précédents ouvrages, parus respectivement en 1978 et 1983, consacrés également à l'étude des faunes recueillies sur ces gisements dans le cadre du Koobi Fora Research Project. 

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. 

This study describes four taxa of Gliridae from the Oligocene mammal locality Gröben 3: Gliravus tenuis BAI-ILO, 1975, Bransatoglis micio (MISONNE, 1957), B. planus (BAHLO, 1975) and B. heissigi n. sp. Gliravus tenuis from Gröben 3 is somewhat more advanced than the type population found in Heimersheim. This confirms previous research suggesting that Gröben 3 should be dated earlier than Heimersheim (MP 24). The first documented occurrence of B. mício around level MP 24 was found in Gröben 3. An abundance of tooth material from B. planus in Gröben 3 makes it possible, for the first time, to observe evolutionary stages within this species from MP 21 until MP 28. B. heissigi n. sp. is restricted to level MP 24. This species is located between B. mísonnei (MP 20 - 23) and Microdyromys praemurinus (MP 25 - 28). Within the lineage Bransatoglis bahloi - B. misonnei - B. heissigi, a decrease in size is noticeable.

  

The middle Palaeocene of São José de ltaboraí (State of Rio de Janeiro, Brazil) has produced a rich and diverse fauna of boid snakes. It comprises six or seven species: Hechtophis austrinus gen. et sp. nov., Corallus priscus sp. nov., Waincophís pressulus sp. nov., Waincophis cameratus sp. nov.,"Boinae A", and "Boinae B". Moreover, two dentaries might pertain to either H. austrinus or "Boinae B", or even represent a distinct taxon. Hechtophis austrinus is assigned, with reservation, to the Erycinae. All other taxa are referred to the Boinae. The vertebrae of all taxa have paracotylar foramina, which raises the problem of the apomorphic or plesiomorphic nature of this feature. This fauna also raises the question of the presence of extinct erycine boids in South America, but it does not allow this question to be settled. 

The subfamilies Murinae and "Dendromurinae" both include 4 species at Chorora. Among the former, while Preacomys nov. gen. seems to be a forerunner of Acomys, the affinities of the remaining, poorly known taxa, are more difficult to evaluate. The bulk of the fauna, remarkably, consists of Dendromurines. Their similarities with those of Ngorora tends to pull the site back in time, but the large size and diversity of Murines fit better an age more recent than the very beginning of the Late Miocene.

  

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

The 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 composition of assemblages of lizards and Amphisbaenian from the European Eocene are described. At least ten lizard families are identified from the lower European Eocene levels. Eight are still recorded in the last level (Escamps) of the late Eocene. Agamid lizards (genus Tinosaurus) died out by the end of the lower Eocene and Varanid lizards (genus Saniwa) disappeared by the beginning of the late Eocene. Amphisbaenians are recorded throughout the Eocene in Europe. The lacertilian fossil record of Europe and North America show a high degree of faunal resemblance in the early Eocene, followed by a decrease during the later part of the epoch. The lacertilian and amphisbaenian faunas from the European Eocene are not subject to great variations during the period; this is in contrast with the mammal record at the same time. It is argued that the low metabolic rates and the ectothermy of lizards could explain those differences, along with the increasing insularity of the West European area during the late Eocene time.

  

On the Track of Ice Age Mammals justifie pleinement son titre car l'auteur, Anthony J. Sutcliffe, apporte au lecteur faits et interprétations qui l'amèneront à s'intéresser encore plus au passé récent et à l'avenir de son environnement et à la question de l'impact de l'homme sur la nature. Après les chapitres qui présentent les temps glaciaires et les divers témoignages qui nous en sont parvenus, les cinquième et sixième apportent les informations nécessaires à la compréhension des résultats que nous donnent les chercheurs: principes, moyens d'étude et limites des méthodes, difficultés de l'intégration des données dans un cadre stratigraphique, variabilité des signaux climatiques, variabilité de leur intensité selon l'endroit par rapport au centre de la glaciation, complications liées à la qualité inégale de l'enregistrement géologique, en mer et sur le continent. 

A new example of parallelism in the dental pattern ofthe Theridomyidae is illustrated by the description ofa new species: Theridomys Iudensis from the standard level of Antoingt (middle Oligocene). Considering the occurence ofthis parallelism phenomenon. the use of numerous qualitative and quantitative criteria is essential to characterize the different stages ofthe different evolutive lineages. Thus, a new simple parameter is proposed (CHY = H+l/0,5 L) to estimate hypsodonty of the medium hypsodont Rodentia. 

La taphonomie (science de l'enfouissement et de la fossilisation) des micromammifères a trop souvent été négligée par rapport à celle des grands mammifères. Or, pour expliquer les concentrations parfois très importantes de microfossiles dans les grottes et les sites préhistoriques il faut connaître les mécanismes qui concourrent actuellement à favoriser les accumulations de ces derniers. C'est le but de l'ouvrage de Peter Andrews qui se décompose en deux parties. 

Cranial anatomy of a late Miocene rhizomyid, Brafhyrhizomys cf. B. pilgrimi, provides new evidence on the origin of the dorsal, round infraorbital foramen of living rhizomyines. Primitive rhizomyids retain a myomorphous keyhole foramen with a long ventral slit that retracts upward during the evolutionary history of the Rhizomyidae. The primitive condition of the elongated ventral slit is represented by Kanisamys sivalensis. Among later burrowers the foramen shows progressive dorsal migration, the ventral slit terminating midway up the snout in B.tertracharax and B. choristos ; well above the midline of the snout in Brachyrhizamys cf. B. pilgrimi. Apparently this transformation began earlier among Rhizomyinae than among Tachyoryctinae and continued to a more derived stage in rhizomyines. ln living Rhizomyx the ventral slit is absent and only a high round hole remains at the anterior end of the zygomatic arch. 

The bovid Mesembriacerus melentisi, the numerous skulls, teeth and limb bones of which are described from the locality Ravin de la Pluie (Macedonia, Greece), bears some features which allow us to put it in the tribe ovibovini (Ovibovinae) with several other Miocene genera and the Recent one Ovibos. A cladogram gives the phyletic relationships within this tribe. It shows that Mesembriacerus which is one of the oldest genera, is also the most primitive. The limb bones are as elongated as those of Recent cursorial bovids and they show, as does the bulk of the fauna, an open environment for the locality. 

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. 

Six orders of birds adapted to aquatic life are represented among the numerous avifauna of "Saint-Gérand-le-Puy": Gaviiformes, Procellariiformes, Pelecaniformes, Ciconiiformes, Phoenicopteriformes, and Anseriformes. The present study of this avifauna proposes several changes in systematics:- Procellariiformes: Puffinus arvernensis does not belong in Procellariidae but in Diomodeidae, and it is transferred to the fossil genus Plotornis previously described in the Middle Miocene of France. - Pelecaniformes: Phalacrocorax littoralis remains in Phalacrocoracidae; P. míocaenus is different from the modern species, and is transferred to the new genus Nectornis. Empheresula arvernensis, described in the Oligocene deposits of Gannat, seems to be present in Saint-Gérand-le-Puy too. Pelecanus gracilis shows many differences from the modern species, and belongs to the new genus Miopelecanus, - Ciconiiformes: Ardea formosa nom. oblit. is a synonym of Proardeola walkeri. - Anseriformes: a new species closely related to swans is described, and belongs to the fossil genus Cygnopterus, of the Middle Oligocene of Europe; this species is called C. alphonsi. The ecology of each species is suggested by comparison with that of its nearest living relatives, and by study of osteological adaptations. 

The genus Cryptomeryx SCHLOSSER, 1886, inusited during a long period, has been discovered in Lower and Middle Oligocene localities of the Quercy region (South-West France). This new material, as well as specimens from the old collections referred to Cryptomeryx, are described; their study, allows us precising the definition of the genus, and confirming its allocation to the Tragulidae family. The type species of the genus, Crypmmeryx gaudryi (= Lophiomeryx gaudryi FILHOL, 1877), occurs in several localities at the base of the Middle Oligocene (Itardies, La Plante 2, Roqueprune 2, Soulce, Herrlingen 1). The new species C. matsoui n. sp. has been defined in the older locality of Mas de Got (top of Lower Oligocene). It is possible that the species Pseudamphimeryx decedens STEHLIN, 1910 pertains to the same genus. Also to the Tragulids must be referred the monospecific genus Iberomeryx (I. parvus GABOUNIA, 1964) from Upper Oligocene of Benara (Georgie, URSS), with which Cryptomeryx is related. These genera are not direct ancestors of Miocene tragulids; their occurrence in the Western European Oligocene results from a first immigration wawe of the family. These Tragulids are one of the most archaic groups of Ruminants. They are probably derived from a primitive stock which had acquired in Asia the selenodont condition of the dentition. 

Perutherium altiplanerise THALER, 1967 from the Late Cretaceous of Peru has long been recognized as South America's oldest known placental mammal. Since its description Perutherium has been generally regarded as having condylarth affinity Based on our identification  of a unique notoungulate synapomorphy we recognize Perutherium as the oldest and the most generalized known member of that order. This new determination and the large taxonomic diversity (five families) of notoungulates in rocks of Paleocene age in Argentina and Brazil, favor a South American origin for this group. The occurrence of notoungulates in rocks of Late Paleocene age in Asia and North America is explained by dispersal of a notoungulate stock from South America to North America and from there to Asia. 

The revision of the old collections of fossil birds from the “Phosphorites du Quercy” and the study of new material give the following results (Gruiformes, Cariamae) :  The humeri and most of the carpometacarpi described under the name Filholornis belong in Elaphrocnemus. The ulnae ascribed to Fïlholornis belong in Idiornis. Most of the post-cranial elements of the genera Elaphrocnemus and Idiornis are described and show great similarities with recent Cariamidae and Opisthocomidae, and fossil Bathornithinae.  A new genus and a new species, Oblitavis insolitus, are created in the sub-family Idiornithinae; two new species are described in the genera Elaphrocnemus (E. brodkorbz) and Idiornis (I. itardiensis), and the species Elaphrocnemus gracilis is transferred to the genus Idiornis.  The genus Propelargus Lydekker is transferred from the family Ciconiidae to Cariamidae.  A new generic name, Occitaniavis, is created for the species Geranopsis elatus, which belong in Cariamidae, while the type-species of the genus, Geranopsis hastingsiae, is a member of the Gruidae.  The affinities between the Quercy avifauna and the Neotropical one is emphasized by the occurrence of Phorusrhacidae, previously known only from the Cenozoic of South America and the Late Pliocene or Early Pleistocene of North America. Thanks to the material collected during the new excavations, the stratigraphical position of most of the species is stated precisely, and evolutionary lineages are outlined. This study shows that the suborder Cariamae, presently restricted to two South American genera, was already extremely diversified during the Eocene, and widespread in Europe and North America.