Mosaicomeryx gen. nov., a ruminant mammal from the Oligocene of Europe and the significance of ‘gelocids’

The description of new material and the reassessment of specimens previously assigned to Gelocus quercyi lead us to propose a new genus for this species, Mosaicomeryx gen. nov. Moreover, the description of a juvenile skull and other specimens of Prodremotherium elongatum, and comparison with Dremotherium, provide evidence that these two genera are not closely related as previously thought. A phylogenetic analysis based on 40 dental, cranial and postcranial features highlights the misidentification of Gelocus quercyi and suggests that Mosaicomeryx gen. nov. is closely related to Prodremotherium elongatum. Mosaicomeryx quercyi and Prodremotherium elongatum form a monophyletic group of stem Pecora that first appeared in Western Europe by the late Early Oligocene (MP25–26), and Prodremotherium elongatum persisted up to MP28; following this time both taxa appear to be replaced by Dremotherium and Amphitragulus. This time interval covers two major Oligocene faunal and climate changes: Extinction 1 (MP24), associated with regression of the inner European sea, and Extinction 3/Migrations 3 (MP28), associated with Late Oligocene Warming

Iberomeryx minor (Mammalia, Artiodactyla) from the Early Oligocene of Soulce (Canton Jura, NW Switzerland): systematics and palaeodiet

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 matte

Classifying fossil Darwin wasps (Hymenoptera: Ichneumonidae) with geometric morphometrics of fore wings.

Linking fossil species to the extant diversity is often a difficult task, and the correct interpretation of character evidence is crucial for assessing their taxonomic placement. Here, we make use of geometric morphometrics of fore wings to help classify five fossil Darwin wasps from the Early Eocene Fur Formation in Denmark into subfamilies and often tribes. We compile a reference dataset with 342 fore wings of nine extant subfamilies and nine relevant fossil species. Since geometric morphometrics was mostly ignored in the past in Darwin wasp classification, the dataset is first used to examine differences and similarities in wing venation among subfamilies. In a next step, we used the reference dataset to inform the classification of the fossil species, which resulted in the description of one new genus and five new species, Crusopimpla weltii sp. nov., Ebriosa flava gen. et sp. nov., Entypoma? duergari sp. nov., Lathrolestes? zlatorog sp. nov., and Triclistus bibori sp. nov., in four different subfamilies. Carefully assessing data quality, we show that the fore wing venation of fossil Darwin wasps is surprisingly suitable to assign them to a subfamily or even lower taxonomic level, especially when used in conjunction with characters from other parts of the body to narrow down a candidate set of potential subfamilies and tribes. Our results not only demonstrate a fast and useful approach to inform fossil classification but provide a basis for future investigations into evolutionary changes in fore wings of ichneumonids. The high informativeness of wing venation for classification furthermore could be harvested for phylogenetic analyses, which are otherwise often hampered by homoplasy in this parasitoid wasp family

Evolution of European carnivorous mammal assemblages through the Palaeogene

The rise of Carnivora (Mammalia: Laurasiatheria) is an important evolutionary event that changed the structure of terrestrial ecosystems, starting at the dawn of the Eocene, 56 Mya. This radiation has been mainly analysed in North America, leaving the evolution of carnivoran diversity in other regions of the globe poorly known. To tackle this issue, we review the evolution of terrestrial carnivorous mammal diversity (Mesonychidae, Oxyaenidae, Hyaenodonta and Carnivoramorpha) in Europe. We reveal four episodes of intense faunal turnovers that helped establish the dominance of carnivoramorphans over their main competitors. We also identify two periods of general endemism. The remaining time intervals are characterized by dispersals of new taxa from North America, Asia and Africa. The European Palaeogene carnivorous mammal fauna appears to have been almost constantly in a transient state, strongly influenced by dispersals. Many of the bioevents we highlight for European carnivorous mammals are probably best seen as ecosystem-wide responses to environmental changes. In contrast to the North American record, European hyaenodonts remain more diverse than the carnivoramorphans for the entire Eocene. The replacement of hyaenodonts by carnivoramorphans as the most diverse and dominant predators only occurred after the ‘Grande Coupure’ at 33 Mya, about 16 Myr later than in North America

A new Late Agenian (MN2a, Early Miocene) fossil assemblage from Wallenried (Molasse Basin, Canton Fribourg, Switzerland)

Excavations of two fossiliferous layers in the Wallenried sand- and marl pit produced a very diversified vertebrate fauna. New material allows the reassessment of the taxonomic position of the ruminant taxa Andegameryx andegaviensis and endemic Friburgomeryx wallenriedensis. An emended diagnosis for the second species is provided and additional material of large and small mammals, as well as ectothermic vertebrates, is described. The recorded Lagomorpha show interesting morphological deviations from other Central European material, and probably represent a unique transitional assemblage with a co-occurrence of Titanomys, Lagopsis and Prolagus. Rodentia and Eulipotyphla belong to typical and well-known species of the Agenian of the Swiss Molasse Basin. Abundant small mammal teeth have allowed us to pinpoint the biostratigraphic age of Wallenried to late MN2a. The biostratigraphic age conforms to data derived from the charophyte assemblages and confirms the oldest occurrence of venomous snake fangs. The palaeoenvironmental context is quite complex. Sedimentary structures and fauna (fishes, frogs, salamanders, ostracods) are characteristic for a humid, lacustrine environment within a flood plain system

The European Ruminants during the " Microbunodon Event " (MP28, Latest Oligocene): Impact of Climate Changes and Faunal Event on the Ruminant Evolution

International audienceThe Earth already experienced numerous episodes of global warming and cooling. One of the latest impressive events of temperature rising was the Late Oligocene Warming that occurred around 25 Mya. An increase of the marine temperature of 2 to 4°C has been observed in a short time interval. In Europe, this major climatic event can be correlated to the continental faunal turnover " Microbunodon Event ". This event is marked by a huge faunal turnover (40% of the ungulate fauna during the first 500k years) and environmental changes. Drier conditions associated to the appearance of the seasonality lead to new environmental conditions dominated by wooded savannahs. This is correlated to a major arrival of Asiatic immigrants. Moreover, from a homogenous fauna during the main part of the Oli-gocene, local climatic variations between the European Western coast and the more central Europe could have provided faunal regionalism during the latest Oligocene and earliest Miocene. Considering the ruminants, this event is the major ever known for this group in Eu-rope. A total renewal at the family level occurred. Thanks to a precise stratigraphic succession , major evolutionary elements are highlighted. Typical Oligocene species, mainly Tragulina, were adapted to wooded environments and were leaves/fruits eaters. They disappeared at the end of MP27 or the early MP28. This corresponds to the appearance of the Asiatic immigrants. The Tragulina (Lophiomerycidae, Bachitheriidae) and stem Pecora gave way to more derived stem and maybe crown Pecora (e.g. " Amphitragulus " , Baba-meryx, Dremotherium). These newcomers were adapted to more open environments and mixed feeding. The disappearance of the Tragulina is probably linked to environmental and vegetation changes, and competition. They give way to more derived ruminants having a more efficient metabolism in drier conditions and a better assimilation of less energetic food

Specimens of <i>Bachitherium lavocati</i> and <i>Bachitherium</i> cf. <i>lavocati</i>.

<p><i>Bachitherium</i> cf. <i>lavocati</i> from <i>Mailhat</i>: <b>1</b> right astragalus (MNHN LIM157), (a) medial, (b) plantar, (c) anterior, and (d) lateral views. <i>Bachitherium lavocati</i> from <i>Pech Desse</i>: <b>2</b> left astragalus (USTL PDS1863), (a) medial, (b) plantar, (c) anterior, and (d) lateral views; <b>3</b> mandible with the teeth p1-m3 (USTL PDS1330, holotype), (a) lingual, (b) occlusal, and (c) labial views. <i>Bachitherium lavocati</i> from <i>Gaimersheim1</i>: <b>4</b> left corpus with the tooth row p2-m3 (SNSB-BSPG 1952II4953), (a) lingual, (b) occlusal, and (c) labial views; <b>5</b> left mandible with the tooth row d3-m3 (SNSB-BSPG 1952II4833), (a) lingual, (b) occlusal, and (c) labial views; <b>6</b> right partial corpus with p3-m1 (SNSB-BSPG 1952II4826), (a) labial, (b) occlusal, and (c) lingual views; <b>7</b> right mandible with m1-m3 (SNSB-BSPG 1952II4910); <b>8</b> left maxillary fragment with D3-D4 (SNSB-BSPG 1952II4857); <b>9</b> left maxillary fragment with the tooth row P3-M3 (SNSB-BSPG 1952II4902). The scale bar is 1 cm.</p

Late Oligocene ruminant paleobiogeography of Western Europe.

<p>Aa Aarwangen; B Boujac; Ba La Barboille; BB Balstahl Bännli; BF Brochene Fluh 19/20; BJ Basel St Jakob; Bu Burgmagerbein1; Cb Comberatière; Ch Les Chauffours; Co Cournon; Di Dieupentale; EK Ebnat Kapel; EL Eriz Lösenegg; G Gaimersheim1; LM La Milloque; Ma Mailhat; PD Pech Desse; PF Pech du Fraysse; Po Portal; R Rickenbach; Ro La Rochette; Rt Romagnat; S Sarèle; Ve Veyron2; V Vazzio; VR Vivel del Rio; Wk Wolfwil kennisbännli; Wy Wynau iii and Wynau V. (T) Tragulina; (P) Pecora. Considered data based on references given for <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0116830#pone.0116830.g007" target="_blank">Fig. 7</a>. Paleogeographical map of the latest Oligocene had been modified from [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0116830#pone.0116830.ref085" target="_blank">85</a>] and [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0116830#pone.0116830.ref086" target="_blank">86</a>].</p