Supp-data 1 – Upper cheek teeth areas of Propalaeotherium sudrei n. sp. from Aumelas compared wit... more Supp-data 1 – Upper cheek teeth areas of Propalaeotherium sudrei n. sp. from Aumelas compared with those of various propalaeotheres. Measures in mm 2 ; ratios in %; in bold, sums and ratios from means.
A new Propalaeotherium species, clearly distinct from the genus Eurohippus, is described. It is c... more A new Propalaeotherium species, clearly distinct from the genus Eurohippus, is described. It is characterized by having a similar size as P. voigti from the German Geiseltal localities (MP 11 to MP 13 reference-level), but differs in several features suggesting a slighty more derived morphology. It presents indeed less brachyodont crowns with less prominent and less elevated cingula, slightly larger relative surface of premolars, and a more marked metaconid splitting on cheek teeth. This new species is unknown from other European localities except the nearby Saint-Martin de Londres locality which has been considered older than the MP 13 level.
Le genre Pachynolophus, un des plus mal connus des Palaeotheriidae, regroupe les formes brachyodo... more Le genre Pachynolophus, un des plus mal connus des Palaeotheriidae, regroupe les formes brachyodontes à prémolaires réduites et non molarisées et à molaires supérieures dépourvues de mésostyle. Des caractères quantitatifs (divers indices de surface et d’allongement des dents) tout en attestant une étroite parenté avec Hyracotherium, permettent une meilleure différenciation du genre, confirment son découpage spécifique et permettent d’y distinguer trois lignées. Un crâne de Memerlein est pris pour type d’une nouvelle espèce, P. lavocati dont la denture est extrêmement caractérisée par sa lophodontie, la forte réduction des prémolaires et l’effacement des cingulums. Cette caractérisation atteste un âge tardif qui prolonge l’existence du genre jusqu’au voisinage de la limite Éocène-Oligocène. Comparé aux deux seuls crânes connus d’espèces apparentées (Hyracotherium vulpiceps et Pachynolophus livinierensis), celui de Memerlein se distingue par des caractères progressifs affectant différentes régions mais plus particulièrement la boîte crânienne, sans qu’on puisse dissocier dans cette évolution la part qui revient à une différenciation systématique. La modernisation se traduit par un important accroissement de taille de la boîte crânienne, principalement dans la région frontale, le développement du massif facial avec un déplacement en avant de la série dentaire et une plus grande spécialisation de l’appareil masticatoire; cette évolution parallélise l’histoire des Equidae du Tertiaire ancien d’Amérique du Nord mais certaines particularités, forme de l’alisphénoïde, présence d’un trou frontal antérieur, structure de l’apophyse paroccipitale, témoignent de l’indépendanee des formes européennes.
A strong lophodonty, an extreme heterodonty, some hypsodonty and regular overlayings of coronal c... more A strong lophodonty, an extreme heterodonty, some hypsodonty and regular overlayings of coronal cement are prominent features of the genus Leptolophus (Palaeotheriinae = Palaeotheriidae s.s.). The histological pattern of the teeth unusually joins type II enamel prisms, characteristic of advanced ungulates, together with archaic features, such as an almost complete lack of Hunter-Schreger zonation and a weak expanse of peritubular dentine. The skull is narrow and slender, with an elongated ante-orbital facial region, a moderately notched nasal aperture, a rather elongated post-canine diastem, parallel zygomatic arches and a fairly dorsally located squamoso-mandibular joint. The functional analysis brings to light “ectolophodont” masticatory cycles with two phases, in which maximum power was applied, contrary to equids, on hindmost teeth; likewise, skull accomodations to increasing height of the teeth are quite different. This study leads to the assumption that Leptolophus may have been light mammals, living in rather open surroundings, browsing on herbaceous plants or leaves cropped close to the ground. Moreover, it appears that it could have been some inadequacy of dental structures to the dietary, which leaded to quick wear of the teeth and to many enamel notches, but had been somewhat balanced by the early increase of hypsodonty, not induced in such a case by a biotop deterioration (as it will happen at the end of the Eocene). This inadaptation might account for the short duration of the genus Leptolophus, whose the 3 species, L. stehlini, L. nouleti and L. magnus n. sp. are indeed confined in the level MP 16. Its geographical spreading (as far as known, South of western Europe) and the morphological pattern of its dentition suggest that this genus would have been related to early upper Eocene endemic spanish forms.
Carnets de Géologie, mémoire 2013/02, p. 105-129, 22 fig, 9 tabl., 4 pl., 2013
Priabonian mammals and reptiles from the Platé Massif (Savoy, France).- A lens of marly limestone... more Priabonian mammals and reptiles from the Platé Massif (Savoy, France).- A lens of marly limestone at the bottom of the Tertiary series of the Grandes Platières (Platé Massif, Savoy) has yielded the most important collection of fossil vertebrates so far known from the Paleogene of Western Alps. Ungulate mammals are represented by 35 teeth to be referred to 9 taxa (4 perissodactyls and 5 artiodactyls). This new fauna appears contemporaneous with that of La Débruge (MP 18 level), dated at about 35.5 My old. The new locality, called "gisement des Perdrix", is stratigraphically located 20-35 m underneath the other one in which WEIDMANN et al. (1991) had found mammals to be attributed to the MP 20 level. So the new fauna is about 1.5 My older than this latter. Its faunal composition and the swampy nature of the deposit suggest that the occurring mammals were living in variegated surroundings, with woody areas close to wet marshy ones.
Key Words : External Alps; Eocene; fossil vertebrates; perissodactyls; artiodactyls
We present here a new revision of the perissodactyls from Robiac, both the MP 16 reference-level ... more We present here a new revision of the perissodactyls from Robiac, both the MP 16 reference-level of the Paleogene mammalian biochronological scale and the type locality of the Robiacian European Land Mammal Age. The locality of Robiac consists actually of two 500m-distant fossiliferous loci, namely Robiac-Nord and Robiac-Sud. According to current biostratigraphic resolution, both loci are considered to be coeval and dated at around -38.7 Ma; Robiac has yielded a very abundant and species-rich perissodactyl fauna composed of 21 taxa. This assemblage is dominated by the last representative of Lophiodontidae, the gigantic Lophiodon lautricense; Robiac being its last ascertained occurrence. The Palaeotheriidae are much diversified with five genera and nine species of “Pachynolophinae” as well as three genera and 10 species of Palaeotheriinae. Robiac is the type locality of nine fossil perissodactyl taxa: Lophiotherium robiacense DEPÉRET, 1917, Leptolophus REMY, 1965 with the species Leptolophus stehlini REMY, 1965 and Leptolophus magnus REMY, 1998, Palaeotherium castrense robiacense FRANZEN, 1968, Anchilophus (Paranchilophus) jeanteti REMY, 2012, Metanchilophus chaubeti REMY, 2012, Chasmotherium depereti n. sp. and Pachynolophus gaytei n. sp. The Robiac mammalian fauna and the associated flora indicate a hot, wet and forested environment, which is supported by the resulting cenogram. The documented interval might correspond to a short warm period. The dislocated bones might have been transported and accumulated in swampy areas along a meandering river. The flourishing mammal fauna of Robiac -the richest one among coeval localities at the European scale- was followed by a drastic decrease in perissodactyl diversity at MP 17a level; such a turnover may be related to a pulse of the first order global cooling which occurred during the Eocene. From Fons 4 (the MP17a reference-level), perissodactyl diversity decreases. Accordingly, the corresponding cenogram indicates a less diversified fauna, with generally smaller species, which could in turn coincide with a cooler and dryer environment. Later on, perissodactyls diversified again in Europe, with the arrival of Asian ceratomorphs.
The knowledge of the Anchilophini has been lately renewed by the discovery of a rather large amou... more The knowledge of the Anchilophini has been lately renewed by the discovery of a rather large amount of new material still largely unpublished. This new material offers the opportunity of a systematic revision of this tribe gathering those of European Eocene Equoidea which bear no mesostyle on upper check teeth and display a heavy trend to the molarization of premolars. A cladistic analysis has made out two genera, Anchilophus (Paranchilophus included as a subgenus), characterized by a marked lophodonty and the transverse narrowness of the cheek teeth, a rather high hypsodonty, the frequent occurrence of crochets and anticrochets on the superior ones, and a rather weak molarization of the premolars, opposite to Metanchilophus n. gen. whose cheek teeth are more transversally elongated, less high, less lophodont, with cusps better distinct, enamel thicker and premolars more molarized on the whole. Three species of Anchilophus are recognized, A. desmaresti, type species of the genus, A. (Paranchilophus) remyi and A. (Paranchilophus) jeanteti n. sp. The genus Metanchilophus is more diversified with the species dumasi, radegondensis, gaudini (whose a new sub-species M. g. fontensis is defined), depereti, castrensis n. sp. and chaubeti n. sp. The skull anatomy has been moreover described with several taxa; it brings to light (for all that one can generalize) that Anchilophini were light animals with a slender and elongated snout, a thin zygomatic arch, a rather developed encephalon with an advanced gyrencephaly. The structure of the nasal opening together with the occurrence of epitympanic sinuses and the molarizing process of the premolars corroborate the attribution of this tribe to the family Palaeotheriidae.
Two new vertebrate local faunas have been discovered in the Célas formation (Gard department, sou... more Two new vertebrate local faunas have been discovered in the Célas formation (Gard department, southern France). The Faveirol local fauna, comprising among others twelve mammal species, is particularly interesting, owing to two skulls of Paleotheriids, which document taxonomic and phylogenetic questions. The Palaeotherium skull is provisionally assigned to the species robustum, but it could as well represent a new species. The Plagiolophus oweni skull brings to light some arguments in favour of phyletic relationships between the subgenus Paloplotherium and the nominotypical subgenus. As for the Pont-de-Ners outcrop, it corresponds to fossiliferous layers revealed and afterwards destroyed during road works between Nîmes and Alès. It yielded but a few and quite fragmentary fossil remains, that nevertheless could likely document a level lightly older than the Célas sandstones.
The genus Plagiolophus is documented, almost solely in Western Europe, from the middle Eocene up ... more 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.
Découverte dans le matériel récolté dans des gisements de mammifères de la zone de Robiac (Eocène... more Découverte dans le matériel récolté dans des gisements de mammifères de la zone de Robiac (Eocène supérieur) : Robiac et formation des sables du Castrais d’un nouveau genre de Paléothéridé. Forme caractérisée par la structure de sa région nasale, son hétérodontie, sa lophodontie et une tendance à l’hypsodontie, précoce dans l’histoire évolutive des Equoidea
A rear skull from the Quercy Phosphorites is described. It documents a new perissodactyl genus, l... more A rear skull from the Quercy Phosphorites is described. It documents a new perissodactyl genus, likely assignable to the family Palaeotheriidae and probably paleogene of age. Owing to the lack of any tooth, this family assignment remains however somewhat hypothetical. The specimen is firstly characterised by the presence of a wide epitympanic sinus swelling and hollowing the squamosal shell and the postglenoid process. This cavity might make up a peculiar pattern of improvement for the hearing apparatus by carrying out a kind of drum near the middle ear, whereas the bony tympanic remains barely bulged and forms but a few developed auditory bulla. This pattern appears an outcome of a trend observed with many palaeotheriids, such as Plagiolophus. Furthermore, the endocranial cast shows a rather high degree of gyrencephaly for a paleogene mammal. The prominent lambdoidal crest points out a powerful nape musculature and a lowered head bearing. Consequently, it is assumed that such an animal was probably living in somewhat open places, at the expense of rather tough vegetables. It might have been accordingly provided with a semi-hypsodont, cernent covered, “plagiolophoid” dentition.
Abundant remains of Mammals and Reptiles were recently recovered in the Gélas sandstones (upper E... more Abundant remains of Mammals and Reptiles were recently recovered in the Gélas sandstones (upper Eocene, department of Gard, France). Their potentialities for fossils, long ago suspected, had not yet been exploited. The composite fauna so collected comprises 35 taxa. Palaeotheriids are playing in it a leading part not only in abundance but also by the quality of specimens which give ample information about cranial and appendicular morphology. Six Palaeotherium species were distinguished, with a new form, P. muehlbergi thaleri, and 2 species of Plagiolophus. Inferences from various systematic units finally lead to the conclusion that the localities concerned are biostratigraphically to be assigned to a level between the La Débruge and Montmartre horizons.
The knowledge of the Anchilophini has been lately renewed by the discovery of a rather large amou... more The knowledge of the Anchilophini has been lately renewed by the discovery of a rather large amount of new material still largely unpublished. This new material offers the opportunity of a systematic revision of this tribe gathering those of European Eocene Equoidea which bear no mesostyle on upper check teeth and display a heavy trend to the molarization of premolars. A cladistic analysis has made out two genera, Anchilophus (Paranchilophus included as a subgenus), characterized by a marked lophodonty and the transverse narrowness of the cheek teeth, a rather high hypsodonty, the frequent occurrence of "crochets" and "anticrochets" on the superior ones, and a rather weak molarization of the premolars, opposite to Metanchilophus n. gen. whose cheek teeth are more transversally elongated, less high, less lophodont, with cusps better distinct, enamel thicker and premolars more molarized on the whole. Three species of Anchilophus are recognized, A. desmaresti, type species of the genus, A. (Paranchilophus) remyi and A. (Paranchilophus) jeanteti n. sp. The genus Metanchilophus is more diversified with the species dumasi, radegondensis, gaudini (whose a new sub-species M. g. fontensis is defined), depereti, castrensis n. sp. and chaubeti n. sp. The skull anatomy has been moreover described with several taxa; it brings to light (for all that one can generalize) that Anchilophini were light animals with a slender and elongated snout, a thin zygomatic arch, a rather developed encephalon with an advanced gyrencephaly. The structure of the nasal opening together with the occurrence of epitympanic sinuses and the molarizing process of the premolars corroborate the attribution of this tribe to the family Palaeotheriidae.
Supp-data 1 – Upper cheek teeth areas of Propalaeotherium sudrei n. sp. from Aumelas compared wit... more Supp-data 1 – Upper cheek teeth areas of Propalaeotherium sudrei n. sp. from Aumelas compared with those of various propalaeotheres. Measures in mm 2 ; ratios in %; in bold, sums and ratios from means.
A new Propalaeotherium species, clearly distinct from the genus Eurohippus, is described. It is c... more A new Propalaeotherium species, clearly distinct from the genus Eurohippus, is described. It is characterized by having a similar size as P. voigti from the German Geiseltal localities (MP 11 to MP 13 reference-level), but differs in several features suggesting a slighty more derived morphology. It presents indeed less brachyodont crowns with less prominent and less elevated cingula, slightly larger relative surface of premolars, and a more marked metaconid splitting on cheek teeth. This new species is unknown from other European localities except the nearby Saint-Martin de Londres locality which has been considered older than the MP 13 level.
Le genre Pachynolophus, un des plus mal connus des Palaeotheriidae, regroupe les formes brachyodo... more Le genre Pachynolophus, un des plus mal connus des Palaeotheriidae, regroupe les formes brachyodontes à prémolaires réduites et non molarisées et à molaires supérieures dépourvues de mésostyle. Des caractères quantitatifs (divers indices de surface et d’allongement des dents) tout en attestant une étroite parenté avec Hyracotherium, permettent une meilleure différenciation du genre, confirment son découpage spécifique et permettent d’y distinguer trois lignées. Un crâne de Memerlein est pris pour type d’une nouvelle espèce, P. lavocati dont la denture est extrêmement caractérisée par sa lophodontie, la forte réduction des prémolaires et l’effacement des cingulums. Cette caractérisation atteste un âge tardif qui prolonge l’existence du genre jusqu’au voisinage de la limite Éocène-Oligocène. Comparé aux deux seuls crânes connus d’espèces apparentées (Hyracotherium vulpiceps et Pachynolophus livinierensis), celui de Memerlein se distingue par des caractères progressifs affectant différentes régions mais plus particulièrement la boîte crânienne, sans qu’on puisse dissocier dans cette évolution la part qui revient à une différenciation systématique. La modernisation se traduit par un important accroissement de taille de la boîte crânienne, principalement dans la région frontale, le développement du massif facial avec un déplacement en avant de la série dentaire et une plus grande spécialisation de l’appareil masticatoire; cette évolution parallélise l’histoire des Equidae du Tertiaire ancien d’Amérique du Nord mais certaines particularités, forme de l’alisphénoïde, présence d’un trou frontal antérieur, structure de l’apophyse paroccipitale, témoignent de l’indépendanee des formes européennes.
A strong lophodonty, an extreme heterodonty, some hypsodonty and regular overlayings of coronal c... more A strong lophodonty, an extreme heterodonty, some hypsodonty and regular overlayings of coronal cement are prominent features of the genus Leptolophus (Palaeotheriinae = Palaeotheriidae s.s.). The histological pattern of the teeth unusually joins type II enamel prisms, characteristic of advanced ungulates, together with archaic features, such as an almost complete lack of Hunter-Schreger zonation and a weak expanse of peritubular dentine. The skull is narrow and slender, with an elongated ante-orbital facial region, a moderately notched nasal aperture, a rather elongated post-canine diastem, parallel zygomatic arches and a fairly dorsally located squamoso-mandibular joint. The functional analysis brings to light “ectolophodont” masticatory cycles with two phases, in which maximum power was applied, contrary to equids, on hindmost teeth; likewise, skull accomodations to increasing height of the teeth are quite different. This study leads to the assumption that Leptolophus may have been light mammals, living in rather open surroundings, browsing on herbaceous plants or leaves cropped close to the ground. Moreover, it appears that it could have been some inadequacy of dental structures to the dietary, which leaded to quick wear of the teeth and to many enamel notches, but had been somewhat balanced by the early increase of hypsodonty, not induced in such a case by a biotop deterioration (as it will happen at the end of the Eocene). This inadaptation might account for the short duration of the genus Leptolophus, whose the 3 species, L. stehlini, L. nouleti and L. magnus n. sp. are indeed confined in the level MP 16. Its geographical spreading (as far as known, South of western Europe) and the morphological pattern of its dentition suggest that this genus would have been related to early upper Eocene endemic spanish forms.
Carnets de Géologie, mémoire 2013/02, p. 105-129, 22 fig, 9 tabl., 4 pl., 2013
Priabonian mammals and reptiles from the Platé Massif (Savoy, France).- A lens of marly limestone... more Priabonian mammals and reptiles from the Platé Massif (Savoy, France).- A lens of marly limestone at the bottom of the Tertiary series of the Grandes Platières (Platé Massif, Savoy) has yielded the most important collection of fossil vertebrates so far known from the Paleogene of Western Alps. Ungulate mammals are represented by 35 teeth to be referred to 9 taxa (4 perissodactyls and 5 artiodactyls). This new fauna appears contemporaneous with that of La Débruge (MP 18 level), dated at about 35.5 My old. The new locality, called "gisement des Perdrix", is stratigraphically located 20-35 m underneath the other one in which WEIDMANN et al. (1991) had found mammals to be attributed to the MP 20 level. So the new fauna is about 1.5 My older than this latter. Its faunal composition and the swampy nature of the deposit suggest that the occurring mammals were living in variegated surroundings, with woody areas close to wet marshy ones.
Key Words : External Alps; Eocene; fossil vertebrates; perissodactyls; artiodactyls
We present here a new revision of the perissodactyls from Robiac, both the MP 16 reference-level ... more We present here a new revision of the perissodactyls from Robiac, both the MP 16 reference-level of the Paleogene mammalian biochronological scale and the type locality of the Robiacian European Land Mammal Age. The locality of Robiac consists actually of two 500m-distant fossiliferous loci, namely Robiac-Nord and Robiac-Sud. According to current biostratigraphic resolution, both loci are considered to be coeval and dated at around -38.7 Ma; Robiac has yielded a very abundant and species-rich perissodactyl fauna composed of 21 taxa. This assemblage is dominated by the last representative of Lophiodontidae, the gigantic Lophiodon lautricense; Robiac being its last ascertained occurrence. The Palaeotheriidae are much diversified with five genera and nine species of “Pachynolophinae” as well as three genera and 10 species of Palaeotheriinae. Robiac is the type locality of nine fossil perissodactyl taxa: Lophiotherium robiacense DEPÉRET, 1917, Leptolophus REMY, 1965 with the species Leptolophus stehlini REMY, 1965 and Leptolophus magnus REMY, 1998, Palaeotherium castrense robiacense FRANZEN, 1968, Anchilophus (Paranchilophus) jeanteti REMY, 2012, Metanchilophus chaubeti REMY, 2012, Chasmotherium depereti n. sp. and Pachynolophus gaytei n. sp. The Robiac mammalian fauna and the associated flora indicate a hot, wet and forested environment, which is supported by the resulting cenogram. The documented interval might correspond to a short warm period. The dislocated bones might have been transported and accumulated in swampy areas along a meandering river. The flourishing mammal fauna of Robiac -the richest one among coeval localities at the European scale- was followed by a drastic decrease in perissodactyl diversity at MP 17a level; such a turnover may be related to a pulse of the first order global cooling which occurred during the Eocene. From Fons 4 (the MP17a reference-level), perissodactyl diversity decreases. Accordingly, the corresponding cenogram indicates a less diversified fauna, with generally smaller species, which could in turn coincide with a cooler and dryer environment. Later on, perissodactyls diversified again in Europe, with the arrival of Asian ceratomorphs.
The knowledge of the Anchilophini has been lately renewed by the discovery of a rather large amou... more The knowledge of the Anchilophini has been lately renewed by the discovery of a rather large amount of new material still largely unpublished. This new material offers the opportunity of a systematic revision of this tribe gathering those of European Eocene Equoidea which bear no mesostyle on upper check teeth and display a heavy trend to the molarization of premolars. A cladistic analysis has made out two genera, Anchilophus (Paranchilophus included as a subgenus), characterized by a marked lophodonty and the transverse narrowness of the cheek teeth, a rather high hypsodonty, the frequent occurrence of crochets and anticrochets on the superior ones, and a rather weak molarization of the premolars, opposite to Metanchilophus n. gen. whose cheek teeth are more transversally elongated, less high, less lophodont, with cusps better distinct, enamel thicker and premolars more molarized on the whole. Three species of Anchilophus are recognized, A. desmaresti, type species of the genus, A. (Paranchilophus) remyi and A. (Paranchilophus) jeanteti n. sp. The genus Metanchilophus is more diversified with the species dumasi, radegondensis, gaudini (whose a new sub-species M. g. fontensis is defined), depereti, castrensis n. sp. and chaubeti n. sp. The skull anatomy has been moreover described with several taxa; it brings to light (for all that one can generalize) that Anchilophini were light animals with a slender and elongated snout, a thin zygomatic arch, a rather developed encephalon with an advanced gyrencephaly. The structure of the nasal opening together with the occurrence of epitympanic sinuses and the molarizing process of the premolars corroborate the attribution of this tribe to the family Palaeotheriidae.
Two new vertebrate local faunas have been discovered in the Célas formation (Gard department, sou... more Two new vertebrate local faunas have been discovered in the Célas formation (Gard department, southern France). The Faveirol local fauna, comprising among others twelve mammal species, is particularly interesting, owing to two skulls of Paleotheriids, which document taxonomic and phylogenetic questions. The Palaeotherium skull is provisionally assigned to the species robustum, but it could as well represent a new species. The Plagiolophus oweni skull brings to light some arguments in favour of phyletic relationships between the subgenus Paloplotherium and the nominotypical subgenus. As for the Pont-de-Ners outcrop, it corresponds to fossiliferous layers revealed and afterwards destroyed during road works between Nîmes and Alès. It yielded but a few and quite fragmentary fossil remains, that nevertheless could likely document a level lightly older than the Célas sandstones.
The genus Plagiolophus is documented, almost solely in Western Europe, from the middle Eocene up ... more 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.
Découverte dans le matériel récolté dans des gisements de mammifères de la zone de Robiac (Eocène... more Découverte dans le matériel récolté dans des gisements de mammifères de la zone de Robiac (Eocène supérieur) : Robiac et formation des sables du Castrais d’un nouveau genre de Paléothéridé. Forme caractérisée par la structure de sa région nasale, son hétérodontie, sa lophodontie et une tendance à l’hypsodontie, précoce dans l’histoire évolutive des Equoidea
A rear skull from the Quercy Phosphorites is described. It documents a new perissodactyl genus, l... more A rear skull from the Quercy Phosphorites is described. It documents a new perissodactyl genus, likely assignable to the family Palaeotheriidae and probably paleogene of age. Owing to the lack of any tooth, this family assignment remains however somewhat hypothetical. The specimen is firstly characterised by the presence of a wide epitympanic sinus swelling and hollowing the squamosal shell and the postglenoid process. This cavity might make up a peculiar pattern of improvement for the hearing apparatus by carrying out a kind of drum near the middle ear, whereas the bony tympanic remains barely bulged and forms but a few developed auditory bulla. This pattern appears an outcome of a trend observed with many palaeotheriids, such as Plagiolophus. Furthermore, the endocranial cast shows a rather high degree of gyrencephaly for a paleogene mammal. The prominent lambdoidal crest points out a powerful nape musculature and a lowered head bearing. Consequently, it is assumed that such an animal was probably living in somewhat open places, at the expense of rather tough vegetables. It might have been accordingly provided with a semi-hypsodont, cernent covered, “plagiolophoid” dentition.
Abundant remains of Mammals and Reptiles were recently recovered in the Gélas sandstones (upper E... more Abundant remains of Mammals and Reptiles were recently recovered in the Gélas sandstones (upper Eocene, department of Gard, France). Their potentialities for fossils, long ago suspected, had not yet been exploited. The composite fauna so collected comprises 35 taxa. Palaeotheriids are playing in it a leading part not only in abundance but also by the quality of specimens which give ample information about cranial and appendicular morphology. Six Palaeotherium species were distinguished, with a new form, P. muehlbergi thaleri, and 2 species of Plagiolophus. Inferences from various systematic units finally lead to the conclusion that the localities concerned are biostratigraphically to be assigned to a level between the La Débruge and Montmartre horizons.
The knowledge of the Anchilophini has been lately renewed by the discovery of a rather large amou... more The knowledge of the Anchilophini has been lately renewed by the discovery of a rather large amount of new material still largely unpublished. This new material offers the opportunity of a systematic revision of this tribe gathering those of European Eocene Equoidea which bear no mesostyle on upper check teeth and display a heavy trend to the molarization of premolars. A cladistic analysis has made out two genera, Anchilophus (Paranchilophus included as a subgenus), characterized by a marked lophodonty and the transverse narrowness of the cheek teeth, a rather high hypsodonty, the frequent occurrence of "crochets" and "anticrochets" on the superior ones, and a rather weak molarization of the premolars, opposite to Metanchilophus n. gen. whose cheek teeth are more transversally elongated, less high, less lophodont, with cusps better distinct, enamel thicker and premolars more molarized on the whole. Three species of Anchilophus are recognized, A. desmaresti, type species of the genus, A. (Paranchilophus) remyi and A. (Paranchilophus) jeanteti n. sp. The genus Metanchilophus is more diversified with the species dumasi, radegondensis, gaudini (whose a new sub-species M. g. fontensis is defined), depereti, castrensis n. sp. and chaubeti n. sp. The skull anatomy has been moreover described with several taxa; it brings to light (for all that one can generalize) that Anchilophini were light animals with a slender and elongated snout, a thin zygomatic arch, a rather developed encephalon with an advanced gyrencephaly. The structure of the nasal opening together with the occurrence of epitympanic sinuses and the molarizing process of the premolars corroborate the attribution of this tribe to the family Palaeotheriidae.
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Un crâne de Memerlein est pris pour type d’une nouvelle espèce, P. lavocati dont la denture est extrêmement caractérisée par sa lophodontie, la forte réduction des prémolaires et l’effacement des cingulums. Cette caractérisation atteste un âge tardif qui prolonge l’existence du genre jusqu’au voisinage de la limite Éocène-Oligocène.
Comparé aux deux seuls crânes connus d’espèces apparentées (Hyracotherium vulpiceps et Pachynolophus livinierensis), celui de Memerlein se distingue par des caractères progressifs affectant différentes régions mais plus particulièrement la boîte crânienne, sans qu’on puisse dissocier dans cette évolution la part qui revient à une différenciation systématique. La modernisation se traduit par un important accroissement de taille de la boîte crânienne, principalement dans la région frontale, le développement du massif facial avec un déplacement en avant de la série dentaire et une plus grande spécialisation de l’appareil masticatoire; cette évolution parallélise l’histoire des Equidae du Tertiaire ancien d’Amérique du Nord mais certaines particularités, forme de l’alisphénoïde, présence d’un trou frontal antérieur, structure de l’apophyse paroccipitale, témoignent de l’indépendanee des formes européennes.
The functional analysis brings to light “ectolophodont” masticatory cycles with two phases, in which maximum power was applied, contrary to equids, on hindmost teeth; likewise, skull accomodations to increasing height of the teeth are quite different. This study leads to the assumption that Leptolophus may have been light mammals, living in rather open surroundings, browsing on herbaceous plants or leaves cropped close to the ground. Moreover, it appears that it could have been some inadequacy of dental structures to the dietary, which leaded to quick wear of the teeth and to many enamel notches, but had been somewhat balanced by the early increase of hypsodonty, not induced in such a case by a biotop deterioration (as it will happen at the end of the Eocene). This inadaptation might account for the short duration of the genus Leptolophus, whose the 3 species, L. stehlini, L. nouleti and L. magnus n. sp. are indeed confined in the level MP 16. Its geographical spreading (as far as known, South of western Europe) and the morphological pattern of its dentition suggest that this genus would have been related to early upper Eocene endemic spanish forms.
Key Words : External Alps; Eocene; fossil vertebrates; perissodactyls; artiodactyls
A cladistic analysis has made out two genera, Anchilophus (Paranchilophus included as a subgenus), characterized by a marked lophodonty and the transverse narrowness of the cheek teeth, a rather high hypsodonty, the frequent occurrence of crochets and anticrochets on the superior ones, and a rather weak molarization of the premolars, opposite to Metanchilophus n. gen. whose cheek teeth are more transversally elongated, less high, less lophodont, with cusps better distinct, enamel thicker and premolars more molarized on the whole.
Three species of Anchilophus are recognized, A. desmaresti, type species of the genus, A. (Paranchilophus) remyi and A. (Paranchilophus) jeanteti n. sp.
The genus Metanchilophus is more diversified with the species dumasi, radegondensis, gaudini (whose a new sub-species M. g. fontensis is defined), depereti, castrensis n. sp. and chaubeti n. sp.
The skull anatomy has been moreover described with several taxa; it brings to light (for all that one can generalize) that Anchilophini were light animals with a slender and elongated snout, a thin zygomatic arch, a rather developed encephalon with an advanced gyrencephaly.
The structure of the nasal opening together with the occurrence of epitympanic sinuses and the molarizing process of the premolars corroborate the attribution of this tribe to the family Palaeotheriidae.
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.
of new material still largely unpublished. This new material offers the opportunity of a systematic revision
of this tribe gathering those of European Eocene Equoidea which bear no mesostyle on upper check
teeth and display a heavy trend to the molarization of premolars.
A cladistic analysis has made out two genera, Anchilophus (Paranchilophus included as a subgenus),
characterized by a marked lophodonty and the transverse narrowness of the cheek teeth, a rather
high hypsodonty, the frequent occurrence of "crochets" and "anticrochets" on the superior ones, and a
rather weak molarization of the premolars, opposite to Metanchilophus n. gen. whose cheek teeth are
more transversally elongated, less high, less lophodont, with cusps better distinct, enamel thicker and premolars
more molarized on the whole.
Three species of Anchilophus are recognized, A. desmaresti, type species of the genus, A. (Paranchilophus)
remyi and A. (Paranchilophus) jeanteti n. sp.
The genus Metanchilophus is more diversified with the species dumasi, radegondensis, gaudini
(whose a new sub-species M. g. fontensis is defined), depereti, castrensis n. sp. and chaubeti n. sp.
The skull anatomy has been moreover described with several taxa; it brings to light (for all that one
can generalize) that Anchilophini were light animals with a slender and elongated snout, a thin zygomatic
arch, a rather developed encephalon with an advanced gyrencephaly.
The structure of the nasal opening together with the occurrence of epitympanic sinuses and the molarizing
process of the premolars corroborate the attribution of this tribe to the family Palaeotheriidae.
Un crâne de Memerlein est pris pour type d’une nouvelle espèce, P. lavocati dont la denture est extrêmement caractérisée par sa lophodontie, la forte réduction des prémolaires et l’effacement des cingulums. Cette caractérisation atteste un âge tardif qui prolonge l’existence du genre jusqu’au voisinage de la limite Éocène-Oligocène.
Comparé aux deux seuls crânes connus d’espèces apparentées (Hyracotherium vulpiceps et Pachynolophus livinierensis), celui de Memerlein se distingue par des caractères progressifs affectant différentes régions mais plus particulièrement la boîte crânienne, sans qu’on puisse dissocier dans cette évolution la part qui revient à une différenciation systématique. La modernisation se traduit par un important accroissement de taille de la boîte crânienne, principalement dans la région frontale, le développement du massif facial avec un déplacement en avant de la série dentaire et une plus grande spécialisation de l’appareil masticatoire; cette évolution parallélise l’histoire des Equidae du Tertiaire ancien d’Amérique du Nord mais certaines particularités, forme de l’alisphénoïde, présence d’un trou frontal antérieur, structure de l’apophyse paroccipitale, témoignent de l’indépendanee des formes européennes.
The functional analysis brings to light “ectolophodont” masticatory cycles with two phases, in which maximum power was applied, contrary to equids, on hindmost teeth; likewise, skull accomodations to increasing height of the teeth are quite different. This study leads to the assumption that Leptolophus may have been light mammals, living in rather open surroundings, browsing on herbaceous plants or leaves cropped close to the ground. Moreover, it appears that it could have been some inadequacy of dental structures to the dietary, which leaded to quick wear of the teeth and to many enamel notches, but had been somewhat balanced by the early increase of hypsodonty, not induced in such a case by a biotop deterioration (as it will happen at the end of the Eocene). This inadaptation might account for the short duration of the genus Leptolophus, whose the 3 species, L. stehlini, L. nouleti and L. magnus n. sp. are indeed confined in the level MP 16. Its geographical spreading (as far as known, South of western Europe) and the morphological pattern of its dentition suggest that this genus would have been related to early upper Eocene endemic spanish forms.
Key Words : External Alps; Eocene; fossil vertebrates; perissodactyls; artiodactyls
A cladistic analysis has made out two genera, Anchilophus (Paranchilophus included as a subgenus), characterized by a marked lophodonty and the transverse narrowness of the cheek teeth, a rather high hypsodonty, the frequent occurrence of crochets and anticrochets on the superior ones, and a rather weak molarization of the premolars, opposite to Metanchilophus n. gen. whose cheek teeth are more transversally elongated, less high, less lophodont, with cusps better distinct, enamel thicker and premolars more molarized on the whole.
Three species of Anchilophus are recognized, A. desmaresti, type species of the genus, A. (Paranchilophus) remyi and A. (Paranchilophus) jeanteti n. sp.
The genus Metanchilophus is more diversified with the species dumasi, radegondensis, gaudini (whose a new sub-species M. g. fontensis is defined), depereti, castrensis n. sp. and chaubeti n. sp.
The skull anatomy has been moreover described with several taxa; it brings to light (for all that one can generalize) that Anchilophini were light animals with a slender and elongated snout, a thin zygomatic arch, a rather developed encephalon with an advanced gyrencephaly.
The structure of the nasal opening together with the occurrence of epitympanic sinuses and the molarizing process of the premolars corroborate the attribution of this tribe to the family Palaeotheriidae.
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.
of new material still largely unpublished. This new material offers the opportunity of a systematic revision
of this tribe gathering those of European Eocene Equoidea which bear no mesostyle on upper check
teeth and display a heavy trend to the molarization of premolars.
A cladistic analysis has made out two genera, Anchilophus (Paranchilophus included as a subgenus),
characterized by a marked lophodonty and the transverse narrowness of the cheek teeth, a rather
high hypsodonty, the frequent occurrence of "crochets" and "anticrochets" on the superior ones, and a
rather weak molarization of the premolars, opposite to Metanchilophus n. gen. whose cheek teeth are
more transversally elongated, less high, less lophodont, with cusps better distinct, enamel thicker and premolars
more molarized on the whole.
Three species of Anchilophus are recognized, A. desmaresti, type species of the genus, A. (Paranchilophus)
remyi and A. (Paranchilophus) jeanteti n. sp.
The genus Metanchilophus is more diversified with the species dumasi, radegondensis, gaudini
(whose a new sub-species M. g. fontensis is defined), depereti, castrensis n. sp. and chaubeti n. sp.
The skull anatomy has been moreover described with several taxa; it brings to light (for all that one
can generalize) that Anchilophini were light animals with a slender and elongated snout, a thin zygomatic
arch, a rather developed encephalon with an advanced gyrencephaly.
The structure of the nasal opening together with the occurrence of epitympanic sinuses and the molarizing
process of the premolars corroborate the attribution of this tribe to the family Palaeotheriidae.