Current issue


June 2024
47-1
<< prev. next >>

Print ISSN: 0031-0247
Online ISSN: 2274-0333
Frequency: biannual

Article Management

You must log in to submit or manage articles.

You do not have an account yet ? Sign up.


Most downloaded articles (last 90 days)


Le genre Plagiolophus (Palaeotheriidae, Perissodactyla, Mammalia): révision systématique, morphologie et histologie dentaires, anatomie crânienne, essai d'interprétation fonctionnelle
Jean-Albert Remy
Keywords: New taxa; Paléogène; perissodactyls; skull anatomy; tooth histology
 
  Abstract

    The genus Plagiolophus is documented, almost solely in Western Europe, from the middle Eocene up to the mid Oligocene (MP 12 to MP 25), i.e. more than for 15 MY. Seventeen species are now recorded whose two of them are new, P. ringeadei nov. sp. and P. mamertensis nov. sp. Some anatomical variations and the deflection of certain evolutionary trends justify the distinction of three subgenera, Paloplotherium, Fraasiolophus nov. and Plagiolophus s.s. The genus displays a wide range in size and weight (between 10 and 150 kg). The detailed description of the skull of several species is here given for the first time.
    Despite important evolutionary drifts during this long time span, the dentition shows a great structural homogeneity, which renders difficult the determination of fragmentary specimens or isolated teeth. It is characterized by a great heterodonty; premolars are little molarized and present a certain regression through time with paradoxically some progress in the molarization. The hypsodonty increases: the first Plagiolophus are hardly less brachyodont than Propalaeotherium, and the last ones are nearly as hypsodont as Merychippus from the early Miocene. The upper molars change from a wide crown pattern, with an open occlusal surface, lightly oblique transverse lophs and rounded internal cusps, to a narrower pattern, with a frontally constricted occlusal surface and internal lophs aligned parallel to the ectoloph. The M3/3 become always longer.

    The dental enamel displays horizontal Schreger-bands with imprecise limits occupying only the middle part of the enamel layer. The dentine is remarkable by its high rate of pericanalicular dentine. The crown cementum, lacking in earlier forms, increases to the point where it fills the occlusal valleys of the
    teeth.

    The masticatory musculature shows a increasing prominence of the temporal, with probably an important role devoted to the pterygoid muscles in lateral movements related to a two-phase type of chewing.

    The evolution of the dentition, of the masticatory musculature and of the repartition of masticatory forces indicate that the Plagiolophus have known different diets through their long evolutionary history; at first browsers they became mixed feeders and finally grazers. Their relatively long neck allowed these animals to reach different vegetal layers. The strength of the nuchal crests also suggests that they were able to have strong backwards movements of the head to pull up their food.

    This evolution of diet seems related to the slow degradation of environmental conditions attested during this period in western Europe, with the generalization of more open landscapes, increasing aridity and more marked seasons.

    Besides, a remodeling of the face is ontogenetically and along time observed, in relation with the evolution of the masticatory apparatus and especially with that of the mandibular lever arm. The postcanine diastemata become longer in the course of evolution; the free extremities of the nasals are always relatively long which contradicts the hypothesis according to which Paloplotherium may have had a trunk. At last the lineage Fraasiolophus can be distinguished by the presence of a deep malar fossa, probably related to a strong development of the maxillo-labialis superior muscle.

    The orbit is always large and tends to increase in size, which indicates a good development of the vision and its increasing role in the life relations. A peculiar type of epitympanic sinus could have been used as a resonance chamber insuring a certain amplification of sounds before their transmission to the eardrum. The endocranial cast reveals a relatively large brain with an advanced degree of gyrencephaly. Beside the role eventually played in food research and social relations, these neurophysiological abilities, also related to an advance in cursorial fitness, could have contributed to the survival of these animals facing the predation pressure of the first fissipede carnivores and the competition with new immigrant herbivores after the "Grande Coupure".
    On the basis of some shared apomorphies with the Pachynolophinae, which prevent from considering the latter as Equidae (molarization of the premolars, reduction of the premaxilla dorsal apophysis, peculiar epitympanic sinus, splitting of the jugular process), the hypothesis of an autochthonous origin of Plagiolophus issued from a form near Propalaeotherium, is once again proposed and discussed. Finally, intra-generic relationships are taken into consideration. 


  Article infos

Published in Vol. 33, Fasc. 1-4 (2004)

PDF
Nouveaux Mammifères Eocènes du Sahara Occidental
Jean Sudre
Keywords: Eocene; Mammals; Occidental Sahara
 
  Abstract

    The fossil mammals collected from the Eocene of Hammada du Dra (northwest Sahara. Algeria) and two fragmentary teeth from the Lutetian of M'Bodione Dadere (Senegal) are described.
    The fossils from the northwest Sahara come from a lacustrian deposit dated by charophytes (Raskyella aff. pecki, Raskyella n. sp.. Maedleriella lavocati, Maedleriella sp. et ? Peckichara sp.) as Middle Eocene or perhaps Lower Eocene (Gevin, Feist and Mongereau, 1974). Several hyracoids (3 or 4) identified from this formation extends the age of the family Pliohyracidae Osborn in Africa. Three forms appear to belong in the genera Megalohyrax, Titanohyrax and perhaps Bunohyrax which have been know until now only from the lower Oligocene of the Fayum (M. gevini n. sp. ; T. mongereaui n. sp.. ? Bunohyrax or Megalohyrax indet.). Another hyracoidof small size is referred to a new genus, Microhyrax (M. lavocati n. sp.).
    Helioseus insolitus n. g. n. sp. is described without ordinal assignment. Azibius (Sudre, 1975) which has been the subject of questions and interpretations is reviewed.
    Only one tooth from the Lutetian of M'Bodione Dadere is complete enough to interpret. lt probably belongs to a condylarth and demonstrates for the first time, the presence of the order in Africa. The second tooth is too fragmentary for comment.
    In conclusion., the paleobiogeographic role of Africa at the end of the cretaceous and the beginning of the Cenozoic is discussed. 


  Article infos

Published in Vol. 09, Fasc. 3 (1979)

PDF
A new species of hippopotamine (Cetartiodactyla, Hippopotamidae) from the late Miocene Baynunah Formation, Abu Dhabi, United Arab Emirates
Jean-Renaud Boisserie, Mathieu Schuster, Mark J. Beech, Andrew Hill and Faysal Bibi
Keywords: Arab Peninsula; Hippopotamidae; Hippopotamine event; Systematics

doi: 10.18563/pv.41.1.e2
 
  Abstract

    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. 


  Article infos

Published in Vol 41-1 (2018)

PDF
S.I. Data
The new Algerian locality of Bir el Ater 3: validity of Libycosaurus algeriensis (Mammalia, Hippopotamoidea) and the age of the Nementcha Formation
Fabrice Lihoreau, Lionel Hautier and Mahammed Mahboubi
Keywords: Dispersal event; Miocene; North Africa; Tetralophodon

doi: 10.18563/pv.39.2.e1
 
  Abstract

    The description of original material of anthracothere and proboscidean in the new locality of Bir el Ater 3 from East Algeria, and a thorough review of early Libycosaurus remains of Bir el Ater 2 allows us validating L. algeriensis as the smallest and earliest species of Libycosaurus and probably the earliest migrant of the genus from Asia. The presence of a Tetralophodon in the Neogene Nementcha formation might represent the earliest occurrence of the genus in Africa. These original fossil remains allow us to discuss the age of the Neogene part of the Nementcha formation close to the Serravalian/Tortonian boundary. 


  Article infos

Published in Vol.39-2 (2015)

PDF
Cryptomerix Schlosser, 1886, Tragulidé de l'oligocène d'Europe ; relations du genre et considérations sur l'origine des ruminants.
Jean Sudre
Keywords: Archaic Ruminants; Paleobiogeography; Quercy Phosphorites; Systematics; Tragulids
 
  Abstract

    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. 


  Article infos

Published in Vol. 14, Fasc. 1 (1984)

PDF
Critical comments on the genus Propachynolophus Lemoine, 1891 (Mammalia, Perissodactyla, Equoidea)
 
Jean-Albert Remy
Keywords: Eocene; Eurohippus; Pachynolophus; Propalaeotherium; tooth morphology

doi: 10.18563/pv.41.1.e3
 
  Abstract

    Abstract
     The validity of Propachynolophus Lemoine, 1891, supposedly an intermediate between Hyracotherium Owen, 1841 and Pachynolophus Pomel, 1847, has been questioned for a long time. A detailed analysis of features on which this genus is based further supported by a formal cladistic analysis demonstrates that Propachynolophus is not a valid taxon. The type species, “Propachynolophus gaudryi Lemoine, 1891” shall be assigned to Propalaeotherium Gervais, 1849, under the new combination Propalaeotherium gaudryi (Lemoine, 1891). “Pachynolophus maldani Lemoine, 1878”, later assigned to Propachynolophus, typifies the new genus Orolophus, under the binomen Orolophus maldani (Lemoine, 1878). The other referred species, “Propachynolophus levei Hooker, 1994” and “P. remyi Checa-Soler, 1997” are poorly documented, and both species shall be provisionally referred to as “Hyracotherium levei (Hooker, 1994) and “Hyracotherium remyi (Checa-Soler, 1997), pending new discoveries.
     
      


  Article infos

Published in Vol 41-1 (2018)

PDF
S.I. Data
Pantolestidae nouveaux (Mammalia, Insectivora) de l'Eocène moyen de Bouxwiller (Alsace).
Jean-Jacques Jaeger
Keywords: Bouxwiller; Insectivora; Mammalia; Middle Eocene; Pantolestidae

doi: 10.18563/pv.3.3.63-82
 
  Abstract

    The Pantolestidae from the middle eocene of Bouxwiller are the subject of a detailed study. Buxolestes hammeli (n. g., n. sp.) is not closely related to any other European or North American form described until now; it presents, however, some characters in common with Pantolestes, a form of the same age from North America. A parallel evolution from a common ancestral form could explain this ressemblance.
    Another form (gen. and sp. indet.) accompanies Buxolertes hammeli in the Bouxwiller fauna.
      


  Article infos

Published in Vol. 03, Fasc. 3 (1970)

PDF
A pangolin (Manidae, Pholidota, Mammalia) from the French Quercy phosphorites (Pech du Fraysse, Saint-Projet, Tarn-et-Garonne, late Oligocene, MP 28)
Jean-Yves Crochet, Lionel Hautier and Thomas Lehmann
Keywords: Oligocene; Pangolin; Pech du Fraysse; Quercy Phosphorites

doi: 10.18563/pv.39.2.e4
 
  Abstract

    Pangolins have never shown a high taxic diversity and their fossil record is scarce. We report here the first discovery of a partial humerus from late Oligocene deposits in Pech du Fraysse (MP28, France). The new specimen from Pech du Fraysse is described and compared to various extant and extinct species of pangolins. It shows a suite of morphological features very similar to the humeri discovered in Saint-André (MP 26), Solnhofen (Burdigalien), and Saulcet (Aquitanian), attributed here to Necromanis franconica. The description of the specimen from Pech du Fraysse allowed us to discuss the systematics of Paleogene and Neogene pholidotans. The differences between PFY 4051 and N. franconica on the one side, and N. quercyi on the other side, might be sufficiently important to justify a generic distinction. A comparison with extant species showed that N. franconica was likely terrestrial and fossorial based on its humeral morphology. 



  Related dataset
  Article infos

Published in Vol.39-2 (2015)

PDF
L'anatomie de Lyrocephaliscus euri (wiman), Trématosaure du Trias inférieur du Spitsberg : arrière-crâne, squelette axial et ceinture scapulaire.
Jean-Michel Mazin and Philippe Janvier
Keywords: skull anatomy; Spitsbergen; Trematosaurs; Trias
 
  Abstract

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


  Article infos

Published in Vol. 13, Fasc. 1-2 (1983)

PDF
Un giraffidae dans le pliocène de Montpellier ?
Claude Guérin
Keywords: Artiodactyla; France; Giraffidae; Mammalia; Montpellier; Ruscinian
 
  Abstract

    An upper giraffid premolar without any indication about its origin is preserved at the Montpellier University among numerous fossils from the ruscinian formation of Montpellier. It can be related to Samotherium, of the Upper Miocene in Eastern Europe, North Africa and Asia, or more probably to Bramatherium  or Hydaspitherium of the Pliocene of South East Asia. The sedimentological study of the matrix shows a calcareous background, which may indicate that this tooth does not come from the Montpellier formation. 


  Article infos

Published in Vol. 16, Fasc. 3 (1986)

PDF
Sur les empreintes de pas des gros mammifères de l'Eocène supérieur de Garrigues-ste-Eulalie (Gard)
Paul Ellenberger
Keywords: Eocene; Euzet; Footprints; Ichnofauna
 
  Abstract

    Is hereby described an impressive lchnoiauna belonging to the Lower to Middle Ludian of the Gard (S. France). The slab, already cleaned over a length of 18 m, is located near the top of the Potamides aporoschema lacustrine limestone (Lower Ludian, Euzet zone). It is therefore older than the Célas sandstone deposit, and still more than the Melanoides albigensis and M. acutus marly limestone corresponding to the Upper Levels of the Ludian stage. Although biostratigraphically older than the La Débruge and Montmartre zone, the biotope shows already a sampling of very tall Artiodactyles, Perissodactyles and Carnivorous. One of the most « majestic ›› Artiodactyles, Anopolotheriipus lavocati, nov., points out a huge size type. To mention also among the Ichnotypes described, 10, the big Perissodactyle Palaeotheriipus similimedius, nov., and the big Carnivorous Hyaenodontipus praedator, nov. 


  Article infos

Published in Vol. 9, Ext (1980)

PDF
La poche à phosphate de Ste-Néboule (Lot) et sa faune de vertebres du Ludien supérieur. 10 - Paléothérides (Perissodactyles).
Jean-Albert Remy
Keywords: Eocene; Quercy Phosphorites
 
  Abstract

    La poche à phosphorite de Sainte-Néboule (Lot) a livré au cours des récentes campagnes de fouilles effectuées dans le cadre de la Rep 311 une douzaine de dents ou fragments de dents de paléothéridés à rapporter à 3 taxons. 


  Article infos

Published in Vol. 08, Fasc. 2-4 (1978)

PDF
Acinoptèrygiens du Stéphanien de Montceau-les-Mines (Saône-et-Loire, France).
Daniel Heyler and Cécile Poplin
Keywords: Aeduelliforms; Biogeography; Palaeonisciforms; paramblypteriforms; Stephanien
 
  Abstract

    The study of new specimens from the Stephanian shales of Montceau-les-Mines confirms and enlarges the number of groups already known in this area. Among the Palaeonisciforms, “form A" is now known more completely, although no diagnosis or name can yet be given for it. “Form B" is redescribed and its relationships with “Elonichthys robisoni" are discussed. A palaeoniscid is recorded which resembles those from Bourbon l'Archambault. The paramblypteriforms occur rather frequently, but no genera can be determined. The aeduelliforms comprise some specimens close to Aeduella blainvíllei from Muse (Autun basin), and a new genus. Comparison of the latter with two fossils from Lally allows creation of two new species and a new family. This diversification of the aeduelliforms during this middle Stephanian leads to the hypothesis that the group originated at least as early the lower Stephanian. This material prooves again the characteristic endemism of this fauna, particularly of the aeduelliforms which are known only in the Massif Central where they diversified during the Permo-Carboniferous. Biogeographical consequences are discussed. 


  Article infos

Published in Vol. 13, Fasc. 3 (1983)

PDF
La poche à Phosphate de Ste-Néboule (Lot) et sa faune de vertebres du Ludien supérieur. 6- Oiseaux
Cécile Mourer-Chauviré
Keywords: Eocene; Quercy Phosphorites
 
  Abstract

    There are very few birds in the site of Sainte-Néboule. They belong to three species already known in the "Phosphorites" : Paraortyx brancoi, Aegialornis broweri, Cypselavus gallicus, and to one new species, Recurvirostra santaeneboulae. The comparison of some different bones of the genus Cypselavus with some Apodiformes and Caprimulgiformes shows that this genus must be classified in the order Apodiformes. 


  Article infos

Published in Vol. 08, Fasc. 2-4 (1978)

PDF
Cricetid rodents from Siwalik deposits near Chinji village. Part I: Megacricetodontinae, Myocricetodontinae and Dendromurinae.
Everett H. Lindsay
Keywords: Dendromurinae; Megacricetodontinae; Middle Miocene; Myocricetodontinae; Rodents; Siwalik
 
  Abstract

    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. 


  Article infos

Published in Vol. 18, Fasc. 2 (1988)

PDF
Designating a lectotype for Mesacanthus pusillus (Gnathostomata: Acanthodii)
Matthew Baron and Kevin Seymour
Keywords: acanthodians; Chordata; Devonian; Midland Valley; Orcadian Basin

doi: 10.18563/pv.44.1.e2
 
  Abstract

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


  Article infos

Published in 44-1 (2021)

PDF
S.I. Data
Sur le plus ancien Lagomorphe Européen et la "Grande Coupure" Oligocène de Stehlin
Nieves Lopez-Martinez and Louis Thaler
Keywords: Grande Coupure; Lagomorphe; Oligocene
 
  Abstract

    Pour la première fois un spécimen de lagomorphe a été récolté en Quercy. L'intérêt de ce fossile tient surtout à son âge géologique inattendu, qui recule considérablement la date de première apparition en Europe de cet ordre de mammifère, Ceci nous paraît justifier une nouvelle réflexion sur la « grande coupure» oligocène, 


  Article infos

Published in Vol. 06, Fasc. 3-4 (1975)

PDF
Autopsie d’une radiation adaptative : Phylogénie des Theridomorpha, rongeurs endémiques du Paléogène d’Europe - histoire, dynamique évolutive et intérêt biochronologique
Monique Vianey-Liaud and Laurent Marivaux
Keywords: Diversification; Extinction; Paléoenvironnements; Rodentia; Theridomyoidea

doi: 10.18563/pv.40.3.e1
 
  Abstract

    Résumé :
    L’étude des rongeurs Theridomorpha permet de suivre le déroulement d’une radiation adaptative pendant toute sa durée (Eocène moyen-Oligocène terminal), sur un territoire restreint à l’extrémité ouest de l’Europe Occidentale. Dans ce papier, la phylogénie de ce groupe est établie à partir d’une analyse cladistique reposant sur l’examen de 315 caractères (310 dentaires). Le groupe d’intérêt comprend 110 des 132 espèces (24 genres) de Theridomyoidea et deux genres encore inclus jusqu’ici dans les Reithroparamyinae qui rejoignent les Theridomorpha. Les groupes externes comprennent des Glires basaux, Cocomys, Tanquammys et 16 Ischyromyiformes. Un cadre phylogénétique robuste est produit, qui permet de clarifier la systématique des Theridomorpha. La position des Remyoidea (nov. sup.fam.) au sein des Ischyromyiformes, extérieure aux Theridomorpha, est confortée. Les Protadelomys et Tardenomys sont à la base des Theridomyoidea, avant la séparation en deux clades correspondant aux familles Pseudosciuridae et Theridomyidae. Les sous-familles sont consolidées : Pseudosciurinae et Sciuroidinae pour les Pseudosciuridae ; Issiodoromyinae, Oltinomyinae, Columbomyinae, Theridomyinae, auxquelles s’ajoute au moins une nouvelle sous-famille (Patriotheridomyinae), pour les Theridomyidae. La topologie des chrono-espèces (sensu Simpson), traitées antérieurement comme lignées évolutives, apparaît dans la plupart des cas sous forme de clades successifs dans lesquels les espèces sont le plus souvent arrangées de manière pectinée, émergeant dans l’ordre stratigraphique. L’analyse des caractères aux principaux nœuds permet de consolider les caractères diagnostiques des taxons et les tendances évolutives, ainsi que de discuter des divers parallélismes et convergences dans l’évolution des structures et patrons dentaires (e.g., émail des incisives unisérié chez les Issiodoromyinae et les Patriotheridomyinae, ou pseudo-multisérié chez les Blainvillimys les plus hypsodontes, les Protechimys et Archaeomys ; patrons dentaires téniodontes ; allongement des dents déciduales chez les Patriotheridomyinae, Issiodoromyinae et Theridomyidae ; sélénodontie ou lophodontie). Les dynamiques évolutives traduites par les changements morphologiques sont mises en relation avec les variations environnementales. Enfin, les implications biochronologiques de l’évolution des Theridomyoidea sont discutées.
    Abstract:
    The adaptive radiation of the rodents Theridomorpha occurred during a limited time window (middle Eocene to late Oligocene), on an area restricted to Western Europe. In this paper, the phylogeny of this group is established via a cladistic assessment of 315 morphological characters (310 dental). The group of interest encompasses 110 upon 132 species (24 genera) of Theridomyoidea, and two genera formerly included within the Reithroparamyinae, and which are included here within the Theridomorpha. The outgroups include basal Glires, Cocomys, Tanquammys and 16 Ischyromyiformes. A robust phylogenetic frame is produced, which allows clarifying the systematics of the Theridomorpha. Within the Ischyromyiformes, the Remyoidea (nov. supfam.) are set apart from the Theridomorpha. Protadelomys and Tardenomys represent the earliest offshoots of the Theridomyoidea, before the dichotomy between Pseudosciuridae and Theridomyidae. It supports the former subfamilies Pseudosciurinae and Sciuroidinae within the Pseudosciuridae; and for the Theridomyidae: the Issiodoromyinae, Oltinomyinae, Columbomyinae, Theridomyinae, with at least one new subfamily (Patriotheridomyinae). The topologies of the chronospecies (sensu Simpson), formerly considered as evolutionary lineages, appear in most cases as successive clades, in which the species are generally pectinately arranged and emerging in the stratigraphic order. The analysis of characters supporting the main nodes allow consolidating the diagnosic characters of the taxa and their evolutionary trends, as well as discussing the various cases of parallelism and convergence in the evolution of structures and dental patterns (e.g., uniserial incisor enamel for Issiodoromyinae and Patriotheridomyinae, or pseudo-multiserial for the most hypsodont Blainvillimys, Protechimys and Archaeomys; taeniodont dental patterns; lengthening of deciduous premolars for Patriotheridomyinae, Issiodoromyinae and Theridomyidae; selenodonty or lophodonty).
    Evolutionary dynamics are analysed with respect to environmental changes. Finally, biochronological implications of the evolution of Theridomyoidea are discussed.
      


  Article infos

Published in Vol 40-3 (2016)

PDF
S.I. Data
Dilambodont Molars :a functional interpretation of their evolution
Percy M. Butler
Keywords: Convergent evolution; Dilambdodont; Molar function; Molar teeth
 
  Abstract

    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. 


  Article infos

Published in Vol. 25, Fasc. 2-4 (1996)

PDF
Contributions à l'étude du gisement Miocène supérieur de Montredon (Hérault). Les grands mammifères. 3 - Les artiodactyles ruminants
Léonard Ginsburg and Herbert Thomas
Keywords: Artiodactyla; France; Montredon; Ruminentia; Upper Miocene
 
  Abstract

    The remains of Ruminantia are very rare at Montredon. No specific determination was possible. We have only one Micromeryx, one small cervid, one tragocere and one (?) gazella. The faunal spectrum is in good correlation with the general retreat of the cervids in the European upper Miocene, but in contrast it is not convenient for the bovids, which are in expansion at the same time. For them, we have to invoke the local ecological conditions.
      


  Article infos

Published in Vol. 18, Ext (1988)

PDF