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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]

We describe nearly complete skeletons of basal Anseriformes from the Latest Paleocene to the early Eocene of North America and Europe. Collectively, these birds appear to be representative of anseriforms near the divergence of Anhimae and Anseres, but their exact positions relative to these clades remains uncertain. A new family, Anachronornithidae nov. fam., is erected on the basis of one of these, Anachronornis anhimops nov. gen., nov. gen. et sp., to which the others cannot be confidently assigned. The new fossils augment a growing collection of early Pan-Anseriformes, which in their diversity do not paint an unambiguous picture of phylogeny or character state evolution on the path to or within crown-Anseriformes. Anachronornis nov. gen. is similar in some aspects of both cranial and postcranial anatomy to other well-represented early Paleogene Anseriformes and members of Anseres, such as Presbyornis Wetmore, 1926. However, it exhibits a more landfowl-like bill, like that of Anhimae and unlike the spatulate bill of Anseres. Additional specimens of similar basal Anseriformes of uncertain affinities from the early Eocene of North America and Europe further complicate interpretation of character state polarity due to the mosaicism of primitive and derived characters they exhibit. [ABSTRACT FROM AUTHOR]

In contrast to the rich collections of articulated spiny-rayed fishes from early Late Cretaceous and Eocene Lagerstätten, similar skeletal remains are sparse in Maastrichtian-Paleocene strata. Here we coin this poorly understood span "Patterson's Gap" and review known articulated skeletons from it, summarizing available information on their phylogenetic affinities, age, and environmental context. Roughly fifty percent of taxa in both the Maastrichtian and Paleocene come from Europe and North America, with percomorphs representing around 60% of the skeletal acanthomorph taxa in each interval. This is higher than the only pre-Maastrichtian assemblage with a reasonable sample of percomorphs, but lower than most Eocene and younger sites. Fossils from Patterson's Gap show a steady accumulation of the principal lineages of spiny-rayed fishes. Material from Paleocene or older strata provides evidence for most of the roughly 20 major acanthomorph divisions recovered by molecular studies. Many fossils from Patterson's Gap remain undescribed and unnamed, and almost none have been included within formal phylogenetic analyses. Revision of existing material, combined with additional fieldwork, should be a priority for future efforts seeking to clarify this murky but significant interval in the evolutionary history of a major vertebrate radiation. [ABSTRACT FROM AUTHOR]

Phenacolophidae is a group of little known archaic ungulates from the Late Paleocene to Middle Eocene of Asia. Its phylogenetic relationships with other altungulates have remained uncertain, partly because most phenacolophids are represented by poorly preserved material. Here we report a new phenacolophid,Sanshuilophus zhaoigen. et sp. nov., from the Lower Eocene Huayong Formation of the Sanshui Basin, Guangdong, China. Although still fragmentary, the new specimens show that the new taxon is characterised by relatively large body size (except forZaisanolophus), sub-molariform premolars, relatively higher bilophodont molars that lack the mesostyle, and tooth enamel microstructure with true prisms and typical Hunter-Schreger bands (HSB). With the new specimens and a review of the published phenacolophid material, we are able to provide an alternative identification for the tooth loci for the type specimen ofPhenacolophusand further present an emended diagnosis for Phenacolophidae. The tooth morphology and enamel microstructure provide new evidence to support the notion that phenacolophids differ from species of Embrithopoda in having low-crown teeth, considerably slanting lophids, distinct paralophids and lacking the arsinoitheriid radial enamel. Phenacolophidae should not be included in Tethytheria but probably represent a stem group for altungulates, if not for all archaic ungulates. [ABSTRACT FROM AUTHOR]

Abstract: Arctostylopids are enigmatic mammals known from the Paleocene and Early Eocene of Asia and North America. Based on molar similarities, they have most often been grouped with the extinct Notoungulata from South and Central America, but tarsal evidence links them to Asian basal gliriforms. Although Palaeostylops is the best-known arctostylopid genus, some points of its content and species level taxonomy remain uncertain. Here we report 255 upper and lower jaw fragments of Palaeostylops, five calcanea, three astragali, as well as the first known arctostylopid distal tibia. This new material was collected from the late Paleocene of the Flaming Cliffs area in Mongolia, in a single lens almost exclusively containing arctostylopid remains. Our study of the morphology and size of the new Palaeostylops dental material confirms the validity of two species, P. iturus and P. macrodon, and illustrates their morphological and biometrical variability and diagnostic differences. The distal tibia of Palaeostylops is relatively unspecialised and resembles the Asian gliriforms Pseudictops and Rhombomylus. We also review the relevance of the historically important genus Palaeostylops in view of other, more recently described but less abundant arctostylopid genera. Palaeostylops remains the reference taxon for the arctostylopid anterior dentition and postcranial morphology. For both anatomical regions, arctostylopids differ significantly from notoungulates, and present a mosaic of characters also seen in basal gliriforms. The notoungulate-like molars of Palaeostylops are highly specialized for arctostylopids and the arctostylopid molar morphotype is therefore better illustrated by the early middle Paleocene Asiostylops. This morphotype does not present any similarities to notoungulates, but shares a number of derived characters with basal gliriforms. Among gliriforms, the primitive arctostylopid morphotype is most similar to Astigale from the early Paleocene of South China, and we suggest that Arctostylopidae may therefore be more closely related to Astigalidae than to any other group. [Copyright &y& Elsevier]

A new neotenic salamander, Seminobatrachus boltyschkensis gen. et sp. nov., is described based on 14 skeletons of late Paleocene-early Eocene age preserved on drill core slabs from the Cherkassy Region, central Ukraine. The new taxon is diagnosed by the following unique combination of characters: dorsal process of premaxilla posteriorly elongate and overlaps frontal; maxilla greatly reduced in size; parietal-squamosal contact absent; vomerine tooth row long and parallel to maxillary arcade; pterygoid has long anterior process; quadrate ossified; marginal and palatal teeth pedicellate; trunk vertebrae amphicoelous, each having a subcentral keel, anterior basapophysis, and spinal nerve foramina; ribs bicipital; carpals and tarsals unossified; and phalangeal formulae of 2-2-3-2 and 2-2-3-4-2 for manus and pes, respectively. Phylogenetic analysis nests S. boltyschkensis within Urodela (i.e., crown-clade salamanders), but its exact phylogenetic position is equivocal, resolving in one of three ways: (1) in an unresolved trichotomy with Salamandra and (Ambystomatidae + (Dicamptodon + Rhyacotriton)) (results obtained in NONA v. 2.0, with the WINCLADA v. 1.00.08 interface; the parsimony ratchet (island hopper) algorithm), (2) as a sister taxon of (Salamandra + (Ambystomatidae + (Dicamptodon + Rhyacotriton))) clade (results obtained in TNT v. 1.1; the implicit enumeration search algorithm) or (3) as a sister taxon of Ambystomatidae (results obtained in PAUP v. 4.0b 10; the branch-and-bound search algorithm). [ABSTRACT FROM AUTHOR]