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Le genre Plagiolophus (Palaeotheriidae, Perissodactyla, Mammalia): révision systématique, morphologie et histologie dentaires, anatomie crânienne, essai d'interprétation fonctionnelle
Published online: 15/12/2004
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.
PV article infos
Published in Vol. 33, Fasc. 1-4 (2004)
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Difficulties with the origin of dinosaurs: a comment on the current debate
Published online: 01/07/2020
Keywords:
dinosaur anatomy; dinosaur evolution; Ornithoscelida; palaeobiogeography; Triassic Period
https://doi.org/10.18563/pv.43.1.e3
Abstract
The origin and early evolutionary history of the dinosaurs is a topic that has recently gone through a period of renewed interest and academic debate. For 130 years, one way of classifying the various dinosaur subgroups persisted as the accepted model, with increasing levels of research in the past quarter-century also providing evidence for the hypothesis that dinosaur origination occurred in the Southern Hemisphere, particularly in South America. It is, after all, from within the Late Triassic strata of countries like Argentina and Brazil that we get some of the very best early dinosaur specimens; many of these specimens are the earliest known representatives of some of the major dinosaur subgroups, such as the theropods and sauropodomorphs. However, some recent analyses have brought about a shift in terms of what is currently accepted and what is now disputed regarding the origin of dinosaurs – the Southern Hemisphere origination hypothesis was questioned (although this was based upon observations and not with quantitative analysis techniques), as has the shape of the dinosaur tree. Responses to the new hypothesis were numerous; many further supported a Southern Hemisphere point of origin. Whilst the interrelationships between the major dinosaur clades remains to be resolved, the current data does seem to comprehensively answer the question of where the dinosaurs first originated. However, it is arguable whether the current data that is being used in such palaeobiogeographical analyses is sufficient to provide an answer to the question of where specifically the dinosaur clade first appeared. This short communication urges a degree of caution about the current consensus and what steps may need to be taken to ensure that more meaningful results are produced in the future.
PV article infos
Published in Vol 43-1 (2020)
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La poche à phosphate de Ste-Néboule (Lot) et sa faune de vertébres du Ludien Supérieur. 2- Amphibiens. Etude Preliminaire
Published online: 25/09/1978
Keywords:
Eocene; Quercy Phosphorites
https://doi.org/10.18563/pv.8.2-4.175-179
Abstract
The Caudata are known by two Salamandridae ; one of them is attributed to the genus Megalotriton. The Pelobatidae form the major part of the Anura ; a few bones indicate also the presence of Neobatrachia.
PV article infos
Published in Vol. 08, Fasc. 2-4 (1978)
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Les rongeurs du Miocène moyen et supérieur du Maghreb
Published online: 15/05/1977
Keywords:
Neogene; North Africa; Rodentia
https://doi.org/10.18563/pv.8..1.1-166
Abstract
The Faunas of Rodents from seven north-african fossiliferous beds distributed from the Middle up to the Uppest Miocene are studied. One genus, seventeen species, one subspecies described are new.
A detailed description is given of the evolution of the numerous specific lines, systematic groups and communities. The evidence of the strong endemism of the North African faunas of that time compared with those of Europe as well as of Tropical Africa is clearly shown. Special relationships with Asia clearly also appear, mostly in the Middle Miocene and the beginning of the Upper Miocene.
Using the specific lines with a biostratigraphic purpose gives the opportunity to establish a biochronological scale for the continental formations of the Maghreb. This scale is calibrated by a few absolute datations. These datations, as well as the stratigraphical study of several fossiliferous localities have given the possibility to establish precise correlations with the corresponding scales of Europe and of Tropical Africa, as well as with the marine formations of the Neogene of occidental Mediterranean sea.
The paleoclimatic data connected with this period in North Africa are explained and the contribution of the micromammals is discussed.
PV article infos
Published in Vol. 08, Fasc. 1 (1977)
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Deux nouveaux primates dans l'Oligocène inférieur de Taqah (Sultanat d'Oman): premiers Adapiformes (?Anchomomyini) de la péninsule arabique?
Published online: 15/11/1993
Keywords:
Adapids; Afro-Arabian plate; Early Oligocene; New taxa; Primates; Trans-Tethyan dispersals
Abstract
Two new species, Omanodon minor n. g., n. sp. and Shizarodon dhofarensis n. g., n. sp., known from fifteen isolated teeth, are described here as the first adapiform primates (?Anchomomyini) recognizable to date in the Taqah material (early Oligocene of Sultanate of Oman).
Omanodon minor n. g., n. sp. displays special morphological similarity to the adapid tribe Anchomomyini from the Eocene of Europe, and especially to the Anchomomys lineage. Resemblances with the extant lemurifonn Microcebus are also noticeable and could be regarded as supporting Schwartz & Tattersall (1983) hypothesis of special relationships between the anchomomyine adapids and the cheirogaleid lemuriformes. However, these morphological affmities can be interpreted, altematively, as the results of parallelisms: important differences in upper molars indicate that the resemblances of cheirogaleids and Omanodon minor n. g., n. sp. are indeed probably due to parallelisms. Phyletic relationship of O. minor n. g., n. sp. to Anchomomyini is finally the most likely hypothesis.
Shizarodon dhofarensis n. g., n. sp., although much more poorly known, is closely related to Omanodon minor n. g., n. sp., at least at a familial level. The general morphology of this species suggests
also a close link with adapid Anchomomyini, although precise relationships within this tribe remain obscure. Interesting resemblances of Shizarodon dhofarensis n. g., n. sp. to Djebelemur martinezi lower molars (early Eocene of Tunisia) are also noticeable. These resemblances are even stronger than those betwen Omanodon minor and Djebelemur martinezi. However the very bunodont upper molars referred to D. martinezi are unusual for adapids, and there are moreover some notable differences in their lower molars. Thus resemblances in Djebelemur and Shizarodon are probably due to paralellisms.
Because of the fragmentary nature of the material and of possible parallelisms, the systematic position of Omanodon and Shizarodon within adapiformes cannot however yet be established definitively.
PV article infos
Published in Vol. 22, Fasc. 4 (1993)
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Rythme et modalités de l'évolution chez les rongeurs à la fin de l'Oligocène-leurs relations avec les changements de l'environnement.
Published online: 15/12/2000
Keywords:
Environment; evolution; Oligocene; Rodents; Systematics
Abstract
The analysis of oxygene isotope variations as well as paleobotanical data suggest that the Oligocene/Miocene boundary corresponds to a transitional period marked by floristical and climatic variations. During this period, the pyreneo-alpine tectonics has contribued to modify the geography and western Europe landscapes. Faunal changes (appearances, extinctions, migrations) are observed in different mammalian groups, notably in the rodents. A study of the evolutionary trends and patterns in paleogene rodents is involved for the period ranging from level MP 28 of the Late Oligocene to the Early Miocene, including the Oligo-Miocene boundary.
The Rodents fauna from the sites of Venelles (Bouches-du-Rhône District, France) and Thezels (Lot, France), previously mentionned in litterature, have been studied. The first description of the Eomyidae of La Milloque (MP 29) has been completed. These faunas are compared to those from various localities dating from the considered period. In La Milloque, a new representative of the Eomys species is described next to a form close to Rhodanomys hugueneyae ENGESSER, 1987. It is the Eomys milloquensis nov. sp., the likely descendant of Eomys quercyi COMTE & VIANEY-LIAUD, 1987. Two new species are also described in Thezels: Eucricetodon thezelensis nov. sp., resulting from a likely and local evolution of Eucricetodon praecursor (SCHAUB, 1925) from La Milloque, which, in the same geographic area, could be at the origin of Eucricetodon hesperius ENGESSER, 1985 from Paulhiac. Plesiosminthus admyarion nov. sp., quite distinct from Plesiosminthus schaubi VIRET, 1926, which announces Plesiosminthus myarion SCHAUB 1930. Venelles 'Plesiosminthus schaubi population is considered as a sub-species, named Plesiosminthus schaubi meridionalis nov. subsp. New phylogenetic patterns are proposed. Among the Eomyidae, a quantification of various features of the M1-2/ crown (hypsodonty, degree of abrasion, occlusal angle, state of development of the I and V anticlines), and a comparison with the occlusal diagram of the other teeth among various other populations allows a more efficient separation of Eomys and Rhodanomys genera. In Western Europe, and within this period, it finally does not seem possible to gradually connect the genus Eomys to the genus Rhodanomys. The evolution of the Eomys quercyi - milloquensis lineage seems to underline a similar evolution to that which may have led from the Eomys to the Rhodanomys form. The latter which appears totally accomplished at level MP 29 of the Oligocene is considered as an immigrant. If we compare the most representative species of the Venelles, Thezels, and Coderet sites, (i.e. Rhodanomys, Eucricetodon, Adelomyarion, Peridyromys, Plesíosminthus), it becomes impossible to confirm their biochronological separation. The noticeable differences between the populations may be interpreted as geographical variations. An explanation to these variations, and to fauna's evolution during the Late Oligocene and Early Miocene can be found in the environmental modifications, supported by isotopic, paleobotanical and sedimentologic analysis. A tentative reconstruction of the environments is attempted by the cenogram method. The analysis of the fluctuations of fauna's diversity shows variations which may be correlated to a drop in temperature at MP 29, during the Late Oligocene, followed by an increase in temperature along with an aridity phenomenom, during the basal Miocene (MN O).The confrontation of various methods give the opportunity of reconstituting and comparing the evolution of the environment of three sequences of sites chosen from different regions. Ecological affinities of various rodents' species are being examined. It is possible to consider that the integration of all the conclusions resulting from this study should lead to an explanation to the evolution of rodents for the period around the Oligocene-Miocene boundary. The site of Coderet- level 3- would be posterior to the latter, at the beginnig of the Miocene, and would mark the level MN 0 of the Aquitanian.
PV article infos
Published in Vol. 29, Fasc. 2-4 (2000)
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Sur la présence de dents de mammifères (Creodonta, Perissodactyla) près de la limite Paléocène-Eocène à Hoegaarden, Belgique
Published online: 16/12/1996
Keywords:
Belgium; Creodonta; Landenian; Mammals; Perissodactyla
Abstract
Amongst a collection of selachian teeth made at Hoegaarden in a marine level of Bruxellian (Lutetian) age, containing a reworked Landenian (Sparnacian) fauna mixed with a contemporaneous one, a few teeth of terrestrial mammals have been discovered. They comprise two rare European taxa: ? Hallensia sp. and Palaeonictis gigantea, both known from the Landenian. Even though the ?Hallensia has not been definitely identified, il differs from the only perissodactyl of this age previously recorded from Belgium (Cymbalophus cuniculus).
PV article infos
Published in Vol. 25, Fasc. 2-4 (1996)
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Avant-propos
Published online: 16/12/1996
Keywords:
D.E.Russell
Abstract
Le présent volume est l'aboutissement d'un projet né il y a presque cinq ans. En décembre 1991, l'un d'entre nous (MG) prenait des contacts en vue de proposer un symposium sur les mammifères fossiles, dédié à D.E. Russell, dans le programme du 4e Congrès de la European Society for Evolutionary Biology. Ce congrès, baptisé "Evolution 93", devait se tenir à Montpellier en août 1993. Son Comité d'Organisation, animé par F. Catzeflis, recherchait des organisateurs de symposiums. L'idée fut acceptée avec enthousiasme par le second d'entre nous (PDG), et le titre de notre Symposium fut précisé: " Palaeobiology and Evolution of Early Cenozoic Mammals - A Symposium in Honor of D.E. Russell". Le projet fut formellement accepté par le Comité d'Organisation en avril 1992.
PV article infos
Published in Vol. 25, Fasc. 2-4 (1996)
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Old world hemiones and new world slender species (Mammalia, Equidae)
Published online: 16/12/2008
Keywords:
Amerhippus; biometry; Equus; Holocene; New World; Old World; Osteology; Pleistocene; Pliocene
https://doi.org/10.18563/pv.36.1-4.159-233
Abstract
Morphological and biometrical description of skulls, teeth, and limb bones of extant and fossil Old World herniones (including E. hydruntinus) and of New World 'stilt-Iegged' and other slender species from Blancan to Holocene. An Appendix presents ways in which the approximate size of some missing bones or dimensions may be deduced from available ones.
The discussed and/or illustrated fossils were found in Bolivia (Tarija), Canada (Yukon), China (Choukoutien, Gulongshan, Jiling, Loufangzi), Ecuador (Oil Fields), Ethiopia (Melka Kunturé), France (Lunel-Viel), Germany (Süssenborn), Greece (Agios Georgios, Petralona), Hungary (Dorog), Italy (Romanelli), Mexico (Cedazo, San Josecito), Mongolia (Sjara-osso-gol), Spain (Venta Micena), ex-Soviet Union (Akhalkalaki, Binagady, Chokurcha, Chukochya, Kabazi, Kolyma, Krestovka, Kurtak, Staroselie, Tologoj), USA (Alaska, Arkalon, Cedar Meadow, Channing, Conkling, Dry Mountains, Hay Springs, Leisey Shell Pit A, Lissie Formation, Natural Trap, Pool Branch, Powers Ranch, Rock Creek, San Diego, Santo Domingo, Seymour Formation, Shelter, Slaton, Trinity River). Numerous raw or statistically elaborated data are given in Tables.
There is no evidence for the existence of Old World hemiones in the New World nor of 'stilt-Iegged' equids in the Old World. The first 'stilt-Iegged' equid was found at Santo Domingo, New Mexico, and is believed to be Late Blancan. It was probably at the origin of E. calobatus (Arkalon, Rock Creek) and of the smaller E. semiplicatus (Channing, Rock Creek). Slender, but not 'stilt-Iegged', equids found at Natural Trap, Wyoming, ca. 12 ky ago belong to Amerhippus. AlI these species share with Oid World Sussemiones (and some hemiones) peculiar patterns on the lower cheek teeth.
The slender Equus sp. B of Leisey Pit A, Florida, ca. 1.2 Ma, as weIl as Amerhippus francisci and E. tau (probably a senior synonym of E. quinni) share conventional lower cheek teeth patterns. The skulls of A. francisci and E. tau, however, are quite different.
Paleontological data suggest a common origin of Amerhippus, Sussemiones, and 'stilt-Iegged' equids during the late Blancan. Old World hemiones seem to have differentiated later.
PV article infos
Published in Vol. 36, Fasc. 1-4 (2008)
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Eggshell microstructure and porosity of the Nicobar scrubfowl (Megapodius Nicobariensis, great Nicobar island, India)
Published online: 16/12/2008
Keywords:
conductance porosity; eggshell microstructure; incubation conditions; Megapodes
https://doi.org/10.18563/pv.36.1-4.75-88
Abstract
The eggshell of Nicobar scrubfowl (Megapodius nicobariensis) is described for the first time. Its egg porosity is calculated and discussed with data from several taxa (another megapode, some extant and fossil reptiles including a titanosaur group) in order to compare incubation types with eggshell structure. Eggshell microstructure reflects first phylogenetic traits and does not seem to have developed major adaptative features due to the incubation conditions, except for the pore canals.
PV article infos
Published in Vol. 36, Fasc. 1-4 (2008)
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New remains of the giant bird Gargantuavis philoinos from the Late Cretaceous of Provence (south-eastern France)
Published online: 27/08/2015
Keywords:
Aves; Gargantuavis; Late Cretaceous; Pelvis; South-eastern France
https://doi.org/10.18563/pv.39.2.e3
Abstract
Two incomplete pelves of the giant bird Gargantuavis philoinos are described from Late Cretaceous deposits at Fox-Amphoux (Var, south-eastern France). They consist of synsacra with attached parts of the ilia. One of them has undergone considerable dorsoventral compression, which makes it very similar in appearance to the holotype pelvis of Gargantuavis philoinos from Campagne-sur-Aude (Aude, southern France). The second specimen has suffered some lateral distortion but is uncrushed dorsoventrally. Because of this, its avians characters (including an arched synsacrum and widespread pneumatisation) are especially clear. These new specimens confirm the avian nature of Gargantuavis and reveal new details about its pelvic anatomy, but provide little new evidence about its systematic position within Aves. The geographical distribution and general rarity of Gargantuavis are discussed.
PV article infos
Published in Vol.39-2 (2015)
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A new rodent from Quaternary deposits of the Canary Islands and its relationships with Neogène and recent murids of Europe and Africa.
Published online: 15/12/1988
Keywords:
Canary Islands; Holocene; Island evolution; Muridae; PHYLOGENY; Rodents; Spain
https://doi.org/10.18563/pv.18.4.241-262
Abstract
A peculiar new rodent, Malpaisomys insularis nov. gen., nov. sp., is described from subfossil deposits of the eastern Canary Islands. The species shows some highly specialized skull features although its molars exhibit a mixture of primitive and derived characters among which a partial stephanodonty is most notable. A comparison of the new rodent with several Miocene to Holocene Muridae shows that Malpaisomys possibly shares a common ancestor with Acomys and Uranomys.
PV article infos
Published in Vol. 18, Fasc. 4 (1988)
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Nouveau Dichobunidae (Artiodactyla, Mammalia) du gisement d'Aumelas (Hérault) d'âge Lutétien terminal
Published online: 01/10/1980
Keywords:
Aumelas; Dichobunidae; Hérault; Middle Eocene; Upper Lutetian
https://doi.org/10.18563/pv.9.ext.197-211
Abstract
The faunal list of the mammals collected at the locality of Aumelas (Hérault, France) is revised. For the first
time this Middle Eocene locality is precisely settled in the european chronological scale of "niveaux repères", between the levels of Bouxwiller and Egerkingen, in Uppermost Lutetian.
A new Dichobunid from the site is described : Aumelasia gabineaudi n. g., n. sp. This new genus has primitive characters. and it may be in the descent of the Lower Eocene Protodichobune.
PV article infos
Published in Vol. 9, Ext (1980)
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A pangolin (Manidae, Pholidota, Mammalia) from the French Quercy phosphorites (Pech du Fraysse, Saint-Projet, Tarn-et-Garonne, late Oligocene, MP 28)
Published online: 14/09/2015
Keywords:
Oligocene; Pangolin; Pech du Fraysse; Quercy Phosphorites
https://doi.org/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.
PV article infos
Published in Vol.39-2 (2015)
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Schmelzmikrostruktur in den inzisiven alt-und neuweltlicher histricognather nagetiere
Published online: 15/12/1992
Keywords:
Africa; Caviomorpha; Ctenodactyloidea; Deseadan; Enamel microstructure; Hunter-Schreger bands; Hystricognathi; Incisors; Ischyromyoidea; multiserial; Paleobiogeography; pauciserial; Phiomorpha; Rodentia; South America
Abstract
Enamel microstructure in the incisors of Old- and New World hystricognath rodents:
The incisor enamel microstructure in more than 100 genera of fossil and Recent hystricognath and sciurognath rodents was studied. A multiserial schmelzmuster is present in the Hystricognathi, the Ctenodactylidae, advanced Chapattimyidae, and in Pedetes. A redefinition of pauciserial and multiserial HSB is given that makes the two enamel types unambiguously distinguishable which apparently represent well defined evolutionary levels. In the pauciserial Schmelzmuster the IPM is thicker than in the multiserial one. In pauciserial HSB the IPM always surrounds each prism, and the crystallites of the IPM run parallel to prism direction; transition zones between HSB are lacking; the inclination of the HSB is normally very low and the prism cross sections are not flattened but somewhat irregular. The number of prisms per HSB is no good distinctive character for pauciserial and multiserial HSB, since there exists a wide overlap. The pauciserial schmelzmuster is primitive, the multiseiial derived because: 1. the pauciseiial schmelzmuster appears earlier in the fossil record in the most primitive rodents (Paramyids s.l. and Ctenodactyloids); 2. the Eocene Ctenodactyloidea show pauciserial HSB but the Oligocene and younger ones are characterized by multiserial HSB; 3. in the outgroup comparison, the Eurymylidae (Mixodontia) show pauciserial HSB; 4. biomechanically, multiserial HSB strenghten the enamel better than pauciserial HSB, since their IPM runs nearly always in an angle of 45° or more to the prisms.
In multiseríal HSB three subtypes can be distinguished which are differentiated by the IPM orientation. Primitive is a (rarely strict) parallel or acute angular, anastomozing IPM, and derived is an interrow sheet-like ("plattenartige") IPM. This evolutionary polarity is indicated by enamel evolution in the Ctenodactylidae which show an acute angular IPM in the Oligocene and a rectangular interrow sheet-like IPM since the Miocene. Among the Caviomorpha a rectangular interrow sheet-like IPM is restricted to the Octodontoidea; therefore they must be considered derived in terms of their enamel structure. The first multiserial HSB in rodent incisors appear in phiomyids or chapatrimyids from the Upper Eocene of Algeria. The IPM is acute angular and anastomozing. The worldwide next younger multiserial HSB are found in Lower Oligocene phiomyids of Fayum, Egypt There already a rectangular interrow sheet like IPM is present (in Metaphiomys) besides the acute angular anastomozing IPM.
The first Caviomorpha from the Deseadan (Oligocene-Miocene) likewise show already acute angular anastomozing IPM (e.g. Scozamys) and rectangular interrow sheet-like IPM (Platypittamys). Therefore the first Caviomorpha cannot be positioned close to a transition from pauciserial to multiserial HSB. In none of the potential caviomorph ancestors from southern North America multiserial HSB or transitional stage between pauciserial and multiserial HSB could be found. The similarities between the enamel types of the Fayum rodents and the rodents from the Deseadan of South America make a derivation of the Caviomorpha from Paleogene North African phiomorph rodents or their direct ancestors most probable. This supports at the same time a descent of the platyrrhine Primates from North African anthropoids.
PV article infos
Published in Vol. 21, Ext (1992)
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Un crane de Chalicothere (Mammalia, Perissodactyla) du Miocène supérieur de Macédoine (Grèce) : remarque sur la phylogénie des Chalicotheiinae
Published online: 14/06/1995
Keywords:
Chalicotheriidae; Cladistics; Greece; Miocene; Perissodactyla; PHYLOGENY
Abstract
The discovery in the Turolian (Late Miocene) of Dytiko 3 (Macedonia, Greece) of a complete skull with mandibles and cervical vertebrae, atlas and epistropheus, is a very important contribution to the knowledge of the subfarnily Chalicotheríinae. After the description, the comparison with other specimens of Miocene chalicotheres permits the revival of the generic name Macrotherium with a new species M. macedonicum. This genus is mainly characterized by a short snout and an inflated cerebral skull. It coexists during the Miocene with Chalicotherium. A cladistic analysis leads to conclusion that the species which has been described from the Early Middle Miocene of Rusinga must be identified as the type-species of a new genus: Butleria.
PV article infos
Published in Vol. 24, Fasc. 1-2 (1995)
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Evolution de la lignée Megacricetodon collongensis-Megacricetotodon roussillonensis (Cricetidae, Rodentia, mammalia) au cours du Midocène inférieur et moyen dans le Sud de la France.
Published online: 14/06/1995
Keywords:
Cricetids rodents; Evolutionary lineage; Lower and Middle Miocene; Mammalian biochronology; Megacricetodon new species; Southern France
Abstract
New populations of the genus Megacricetodon have recently been discovered in Southern France.Two new species are defined: M. lemartineli n. sp. and M. fournasi n. sp., their stages of evolution are intermediate between those of M. gersii and M. roussillonensis. Morphological and biometrical analysis indicate the presence of only one lineage: M. collongensis--M. collongensis-gersii--M. gersii--M.lemartineli nov. sp.--M. fournasi nov. sp. and M. roussillonensis. This observation allows to refine the chronology based on rodents, for the Late Early Miocene and the Middle Miocene in the Southern France.
Comparisons with some iberian species are done. The validity of the French species M. bezianensis and M. bourgeoisi is discussed.
PV article infos
Published in Vol. 24, Fasc. 1-2 (1995)
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Les poissons crétacés et tertiaires du bassin des Iullemmeden (République du Niger)
Published online: 15/09/1972
Keywords:
Actinopterygians; Cenozoic; Cretaceous; Dipnoans; Selachians
https://doi.org/10.18563/pv.5.5.179-251
Abstract
The present work is devoted to the study of the Cretaceous and Tertiary fishes (teeth of Selachians, Actinopterygians and Dipnoans) collected during a recent expedition in Niger. The Maestrichtian localities have yielded a new genus and a new subspecies of Selachian: Igdabatis sigmodon nov. gen., nov. sp. and Lamna biauriculata nigeriana nov. subsp. The locality of Sessao, which has been attributed to the Thanetian by means of the study of the fish, has furnished by screen-washing an interesting fauna wherein six new species are described: Raja Iouisi, Dasyatis sessaoensis, D. sudrei, D. russelli, Hypolophites thaleri and Ceratodus casieri. Comparison of these faunas with contemporary faunas of Africa has brought out a certain endemism in the Iullemmeden Basin during the late Cretaceous and the early Tertiary.
PV article infos
Published in Vol. 05, Fasc. 5 (1972)
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Les traces de pas de Dinosaures et autres Archosaures du Lias inférieur des grands Causses, Sud de la France
Published online: 15/12/2002
Keywords:
Dinosauroid footprints; France; Grands-Causses; Hettangian; ichnostratigraphy; paleoenvironments; Sinemurian; statistical results
https://doi.org/10.18563/pv.31.1-4.1-143
Abstract
The Causses" is a near 3400 km2 large plateau located in the south of France. Here the first dinosaur footprints where found in 1935. After this, this area has yielded an ever-increasing number of ichnites now in excess of 500 specimens. These latter, 15 to 50 cm long, tridactyl or tetradactyl footprints of generally biped animals, were discovered at the surface of Hettangian to lower Sinemurian dolomite layers within 4 distinct stratigraphic units. The 35 sites bearing ichnites are located on the plateau margin. For the first time, morphologic characters studied through descriptive statistic methods with the usual parameters and classical Student and Snédecor tests, allowed us, to divide the whole set of biped traces into 6 ichnospecies. Their definitions are further constrained by multivariate statistical results using Principal Component Analysis (PCA), Factor Analysis of correspondances (FAC) and Discriminant Analysis (DA). All have confirmed the morphologic observations. So that now, the following taxa are identified : Grallator variabilis, G. lescurei, G. sauclierensis, G. minusculus, Eubrontes giganteus, Dilophosauripus williamsi, cf. Moraesichnium, Orníthopus fabrei nov ichnosp. The more immediately visible differences relate to the interdigital II-IV divarication and the digit length ratio. To this panel, we must add Batrachopus deweyi and shapes suggesting Trisauropodichnus and/or Anomoepus. Among all ichnite associations described in the lower Liasic, the New England assemblage presents the most affinities with ours. It shows the ichnotaxa Grallator, Dilophosauripus, Eubrontes, Batrachopus without forgetting Ornithopus fabrei nov. ichnosp. which is close to Ornithopus gallinaceus from the Massachusetts and Connecticut basins. On comparing the present early Jurassic ichnofauna of the Causses with the ones of the Middle and Upper Triassic formations of the eastem border of the Massif Central (France), it appears that tridactyl footprints become more and more numerous and large from Triassic to Early Jurassic. In the Causses, these latest are prevalent but in Quercy (France), Poland, Italy, USA, they are also associated with Omithopoda, Thyreophora and Sauropoda ichnites. Footprint areas considered here were generaly under an arid climate. Animals that passed by were heavy and bulky possible Megalosaur trackmakers, and lighter and slender Coelophysids or Ceratosaurs. For all, these areas were pathways as the orientations of the trackways seem point out. The directions followed by these reptiles were without any important variation during the Hettango-Sinemurian stages. These areas were also used from time to time by Crocodilomorpha and may be tetradactyl (I-IV) bipedal avian Theropods. However, the number of such trackways in sites, sometimes substantial, should not lead us to overestimate the trackmakers populations. These last were probably relatively moderately abondant in this inter-supratidal swamp environment. In the Causses, ichnites are connected with former algo-laminated deposits (Algal mats) which were rapidly hardened by means of calcitisation of cyanobacteria. The result has been a moderate depth of footprints; autopodia disturbing only a few cm of the carbonate substrate. Other fossils have been discovered : invertebrates with thin bivalve and gastropod shells, crustaceans tests and plants. These latter suggest the existence of paleomangroves like environments but also continental vegetation periodically overruning the swamp environment during regression/transgression cycles. At these times, wooded parts of it, could become protecting, feeding, resting and nesting places.
PV article infos
Published in Vol. 31, Fasc. 1-4 (2002)
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The Gliridae (Mammalia) from the oligocene (MP24) of Gröben 3 in the folded molasse of southern Germany
Published online: 28/12/2001
Keywords:
Biostratigraphy; Cyrena Beds; folded molasse; Germany; Gliridae; level MP 24; Mammals; Oligocene; Palaeoecology
Abstract
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.
PV article infos
Published in Vol. 30, Fasc. 3-4 (2001)
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