Mennecart B.,University of Fribourg |
Becker D.,Section dArcheologie et Paleontologie |
Berger J.-P.,University of Fribourg
Swiss Journal of Geosciences | Year: 2011
The primitive ruminant genus Iberomeryx is poorly documented, as it is essentially only known from rare occurrences of dental remains. Therefore, the phylogeny and palaeobiology of Iberomeryx remain rather enigmatic. Only two species have been described: the type species I. parvus from the Benara locality in Georgia, and the Western European species I. minor reported from France, Spain, and Switzerland. Iberomeryx savagei from India has recently been placed in the new genus Nalameryx. All these localities are dated to the Rupelian and correspond mainly to MP23 (European mammal reference level). Based on the short height of the tooth-crown and the bunoselenodont pattern of the molars, Iberomeryx has often been considered as a folivore/frugivore. The I. minor remains from Soulce (NW Switzerland) are preserved in Rupelian lacustrine lithographic limestones. One specimen from this locality represents the most complete mandible of the taxon with a partially persevered ramus. Moreover, the unpreserved portion of the mandible left an imprint in the sediment, permitting the reconstruction of the mandible outline. Based on a new description of these specimens, anatomical comparisons and Relative Warp Analysis (24 landmarks) of 94 mandibles (11 fossil and 83 extant) from 31 ruminant genera (10 fossil and 21 extant) and 40 species (11 fossil and 29 extant), this study attempts a preliminary discussion of the phylogeny and the diet of the species I. minor. The results permit to differentiate Pecora and Tragulina on the first principal component axis (first Relative warp) on behalf of the length of the diastema c/cheek teeth, the length of the premolars and the angular process. The mandible shape of I. minor is similar to those of the primitive Tragulina, but it differs somewhat from those of the extant Tragulidae, the only extant family in the Tragulina. This difference is essentially due to a stockier mandible and a deeper incisura vasorum. However, in consideration of the general pattern of its cheek teeth, I. minor as well as possibly Nalameryx should be considered to represent the only known primitive Tragulidae from the Oligocene. Moreover, I. minor should have been a selective browser (fruit and dicot foliage) but, similarly to small Hypertragulidae and Tragulidae, may also have exceptionally consumed animal matter. © 2010 Swiss Geological Society.
Scherler L.,Section dArcheologie et Paleontologie |
Mennecart B.,University of Fribourg |
Hiard F.,University of Fribourg |
Becker D.,Musee Jurassien des science Naturelles
Swiss Journal of Geosciences | Year: 2013
The biostratigraphy and diversity patterns of terrestrial, hoofed mammals help to understand the transition between the Palaeogene and the Neogene in Western Europe. Three phases are highlighted: (1) the beginning of the Arvernian (Late Oligocene, MP25-27) was characterised by a "stable" faunal composition including the last occurrences of taxa inherited from the Grande Coupure and of newly emerged ones; (2) the latest Arvernian (Late Oligocene, MP28-30) and the Agenian (Early Miocene, MN1-2) saw gradual immigrations leading to progressive replacement of the Arvernian, hoofed mammals towards the establishment of the "classical" Agenian fauna; (3) the beginning of the Orleanian (Early Miocene, MN3-4) coincided with the African-Eurasian faunal interchanges of the Proboscidean Datum Events and led to complete renewal of the Agenian taxa and total disappearance of the last Oligocene survivors. Faunal balances, poly-cohorts and particularly cluster analyses emphasise these three periods and define a temporally well-framed Oligocene-Miocene transition between MP28 and MN2. This transition started in MP28 with a major immigration event, linked to the arrival in Europe of new ungulate taxa, notably a stem group of "Eupecora" and the small anthracothere Microbunodon. Due to its high significance in the reorganisation of European, hoofed-mammal communities, we propose to name it the Microbunodon Event. This first step was followed by a phase of extinctions (MP29-30) and later by a phase of regional speciation and diversification (MN1-2). The Oligocene-Miocene faunal transition ended right before the two-phased turnover linked to the Proboscidean Datum Events (MN3-4). Locomotion types of rhinocerotids and ruminants provide new data on the evolution of environments during the Oligocene-Miocene transition and help understand the factors controlling these different phases. Indeed, it appears that the faunal turnovers were primarily directed by migrations, whereas the Agenian transitional phase mainly witnessed speciations. © 2013 Swiss Geological Society.
Anquetin J.,Section dArcheologie et Paleontologie |
Anquetin J.,French Natural History Museum |
Milner A.R.,Natural History Museum in London
Comptes Rendus - Palevol | Year: 2015
The enigmatic vertebrate taxon Cyrtura temnospondyla is reassessed following the location and reuniting of both counterparts. The specimen, comprising a series of caudal vertebrae from the Tithonian Solnhofen Limestone, has variously been interpreted as derived either from a temnospondyl amphibian, or a turtle, or to be indeterminate. The redescription of this caudal series reveals that the vertebrae have a single centrum, in contrast to previous descriptions. This specimen is here interpreted to be the tail of a turtle more derived than Proganochelys and Meiolania, but is otherwise indeterminate and cannot be associated with any of the diagnosed taxa from the Solnhofen Limestone. C. temnospondyla lacks any diagnostic character and must therefore be considered a nomen dubium. © 2014 Académie des sciences.
Becker D.,Section dArcheologie et Paleontologie |
Antoine P.-O.,Montpellier University |
Maridet O.,CAS Institute of Vertebrate Paleontology and Paleoanthropology
Journal of Systematic Palaeontology | Year: 2013
A newly discovered, well-preserved skull and associated fragment of a juvenile mandible from the Early Oligocene locality of Poillat (Canton Jura, NW Switzerland), bearing close affinities with the rhinocerotid Protaceratherium albigense (Roman, 1912), are attributed to a new small-sized representative of early diverging Rhinocerotinae, Molassitherium delemontense gen. et sp. nov. Other specimens from Western Europe, formerly questionably referred to Epiaceratherium Abel, 1910, are assigned to this new genus. Comparison with the previously described Protaceratherium Abel, 1910 (including type material) and a phylogenetic analysis highlight the mismatch of Protaceratherium minutum (Cuvier, 1822) and Protaceratherium albigense (Roman, 1912). Given the topology of the most parsimonious tree, a basal split within Rhinocerotidae coincides with the well-supported divergence of the Elasmotheriinae and Rhinocerotinae clades. Relationships within Rhinocerotinae are [Epiaceratherium bolcense Abel, 1910 [Epiaceratherium magnum Uhlig, 1999 [Molassitherium gen. nov. [Mesaceratherium Heissig, 1969 [Pleuroceros Roger, 1898 [Protaceratherium minutum (Cuvier, 1822) [Plesiaceratherium mirallesi (Crusafont, Villalta and Truyols, 1955) [Aceratheriini, Rhinocerotini]]]]]]]]. The only paraphyletic genus in the analysis is Epiaceratherium, with the earliest Oligocene Epiaceratherium bolcense Abel, 1910 being sister taxon to an [Epiaceratherium magnum Uhlig, 1999, Rhinocerotinae] clade. In the single most parsimonious tree, Molassitherium gen. nov., included within the early diverging Rhinocerotinae, forms a clade encompassing Molassitherium delemontense gen. et sp. nov. and the type species Molassitherium albigense comb. nov. The range of Molassitherium delemontense gen. et sp. nov. is so far restricted to the late Early-early Late Oligocene interval in Western Europe (Germany, Switzerland, France; late MP22-MP25). © 2013 Copyright Taylor and Francis Group, LLC.
Anquetin J.,Section dArcheologie et Paleontologie
PeerJ | Year: 2015
Background. In a recent paper, we proposed a lectotype for the species Plesiochelys langii Rütimeyer, 1873. However, we failed to register this publication in ZooBank as required by the International Commission on Zoological Nomenclature (ICZN) for electronic publication. Although our conclusions remain unchanged, this particular nomenclatural act cannot be considered as published under ICZN regulations. Results. The present work fulfills the requirements of the ICZN for a lectotype designation and has been registered in ZooBank. © 2015 Anquetin.