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After about a century, the skull of the holotype and sole specimen of Arambourgia gaudryi from the Eocene of Quercy (France) is here redescribed. Its interest resides in its extreme morphology, such as its very small skull and altirostral condition, that raises questions about its maturity, taxonomic validity, and paleoecology. In order to reveal previously hidden anatomical details, we used computed microtomography (µCT-scan) data to digitally extract the bones of the cranium and mandible, as well as the endocranial structures. Here, we update the osteological description of A. gaudryi, outlining new characters and re-evaluating anatomical details. Comparing it with ontogenetic series of extant crocodylians, we confirm that the specimen is a mature individual of a dwarf species with pedomorphic features. Our phylogenetic analyses indicate that A. gaudryi is an alligatorine. Comparisons with other small alligatoroid taxa show that it is indeed a valid species. The depositional environment of the finding site suggests a continental context with a karstic network. Taking this into account, together with its peculiar anatomy, we propose that A. gaudryi was a semi-terrestrial animal occupying an ecological niche similar to that of extant juvenile or dwarf crocodylians. Finally, we discuss the current knowledge of the paleobiogeography of Alligatoroidea in Europe during the Paleogene. Arambourgia gaudryi was likely part of a group of small early globidontans that arrived in the Old World, probably from North America, around the end of the Paleocene and that dispersed to at least four localities of the ancient European archipelago. [ABSTRACT FROM AUTHOR]

‘Arctocyonids’ are generally considered as including some of the most primitive ‘ungulates’ from the Paleocene. Although more than 15 genera are known from North America, European members of this order are less common and mainly belong to derived genera such asArctocyon. However, one species of primitive arctocyonid,Prolatidens waudruae, was described from the early Paleocene of Hainin, Mons Basin, Belgium. Here we describe new dental positions of this small taxon, including for the first time upper molars and upper fourth premolar. Morphological comparisons confirm the position ofP. waudruaeamong primitive ‘ungulates,’ with the closest North American arctocyonids beingProthryptacodon furensandOxyprimus galadrielae.Oxyprimus galadrielaefeatures slightly more primitive morphological traits than both other species. Apheliscids share several characters withProlatidens, but the latter lacks the apomorphies defining the family. Among ‘arctocyonids,’Prolatidensshares with onlyProtungulatumandOxyprimusthe incomplete lingual cingulum at the base of the protocone of M1.Prolatidens waudruaeis unique among Procreodi in its combination of primitive and derived characters. The cladistic analysis placesP. waudruaeclose to the base of the ingroup, indicating that this species is among the most primitive members of the Paleocene ‘ungulates.’ However, the lower nodes of the trees are not well supported and definitive conclusions should await more complete specimens and analysis. Apheliscids are situated relatively far fromProlatidens, suggesting that the resemblances between them are better considered as convergences. Based on the morphological comparisons, the arctocyonid from Hainin correlates best with North American Torrejonian taxa. [ABSTRACT FROM PUBLISHER]

We report the discovery of the earliest European carnivoraforms, based on two new taxa from the latest Paleocene of France and Romania. A new species of Vassacyon, V. prieuri, from the locality of Rivecourt (MP6b; Oise, France) (MP = Mammalian Paleogene reference levels) is described based on a dentary fragment and isolated teeth. This species displays several primitive features compared with species of Vassacyon known from the early Eocene of North America and Europe. A second Paleocene carnivoraform, cf. Gracilocyon sp., is described based on fragmentary specimens from the locality of Jibou (MP6b; Transylvania, Romania). Carnivoraformes were previously unknown in Europe before the Eocene, and Vassacyon prieuri and cf. Gracilocyon sp. are their oldest records in Europe. These discoveries favor the hypothesis of a dispersal of these two genera from Europe to North America during the Paleocene-Eocene Thermal Maximum. Vassacyon prieuri and cf. Gracilocyon sp. strengthen support for the level MP6b and its correlation with the Clarkforkian. The geographic origin of the Carnivoraformes remains unknown. However, based on the observed biochronological and geographic distributions of the carnivoraforms, we infer a possible Asian origin for this group. In this scenario, Gracilocyon and Vassacyon dispersed to Europe during the Clarkforkian MP6b time, probably together with rodent taxa, whereas Uintacyon dispersed from Asia to North America shortly after rodents and tillodonts. http://zoobank.org/urn:lsid:zoobank.org:pub:FC885E7F-877A-4454-9902-DF118B8C8693 SUPPLEMENTAL DATA—Supplemental materials are available forthis article for free at www.tandfonline.com/UJVP Citation for this article: Solé, F., T. Smith, E. de Bast, V. Codrea, and E. Gheerbrant. 2016. New carnivoraforms from the latest Paleocene of Europe and their bearing on the origin and radiation of Carnivoraformes (Carnivoramorpha, Mammalia). Journal of Vertebrate Paleontology. DOI: 10.1080/02724634.2016.1082480. [ABSTRACT FROM AUTHOR]