Late Eocene Locality Research Articles

Taxonomic revision of the snakes of the genera Palaeopython and Paleryx (Serpentes, Constrictores) from the Paleogene of Europe

Large constrictor snakes, referred to the genera Palaeopython and Paleryx, are an ecologically prominent part of the fauna of Europe during the Paleogene. Most species were named over a century ago and their taxonomy is largely based on isolated vertebrae. Furthermore, the majority of named taxa originate from imprecisely known localities within the Phosphorites du Quercy, in southern France, and thus their exact age is not known. We critically review and re-diagnose these genera based on personal examination of all existing type material, an array of new specimens, and a detailed literature review. We consider Palaeopython and Paleryx to be valid and propose vertebral characters to distinguish them. We recognize three valid species of Palaeopython, i.e. Palaeopythoncadurcensis (type species) from the Phosphorites du Quercy, Palaeopythonceciliensis from Geiseltal, and Palaeopythonhelveticus from Dielsdorf (Switzerland), and one valid species of Paleryx, i.e. Paleryxrhombifer (type species) from Hordle Cliff (England). Four other species, which were previously treated as members of Palaeopython and Paleryx, i.e. “Palaeopython” filholii and “Palaeopython” neglectus from the Phosphorites du Quercy, “Palaeopython” fischeri from Messel, and “Paleryx” spinifer from Geiseltal, are also considered as valid but pertain to other genera. Among these four taxa, “Palaeopython” fischeri has been recently assigned to its own genus, Eoconstrictor. A new genus, Phosphoroboa gen. nov. is established to accommodate “Palaeopython” filholii. We designate a lectotype for Palaeopythoncadurcensis and establish that the paralectotype maxilla and dentary are reasonably referred to this species. New material attributed to Palaeopythoncadurcensis is described from the old collections of the Phosphorites du Quercy. Paleryxcayluxi, another species established from the old collections of the Phosphorites du Quercy, is synonymized here with Palaeopythoncadurcensis. We further clarify important errors in the original description and figures of Paleryxcayluxi, identify the exact specimens that comprise the type series, and designate a lectotype. Much new material is described for Palaeopythonceciliensis from its type area in Geiseltal and intracolumnar variation is considered. We describe additional vertebral and cranial material of Paleryxrhombifer from its type area in Hordle Cliff. Based on this cranial material, we suggest non-booid affinities for Paleryxrhombifer. We designate a lectotype for Paleryxdepressus and agree with its previous suggested synonymy with Paleryxrhombifer. We re-describe the lectotype and paralectotypes of “Palaeopython” neglectus and refer and describe new material of this species from the Phosphorites du Quercy, paying special attention to intracolumnar variation; we also defer a decision on its generic relations until more abundant and complete material can be studied. We describe new vertebral material of the booid Eoconstrictor cf. fischeri from Geiseltal; similar material was previously known only from Messel and Dielsdorf. We determine that Eoconstrictorfischeri contains two distinct and unrelated species and describe intracolumnar variation in the nominotype. We clarify certain issues regarding the type series of Paleryxspinifer, designate a lectotype, and report previously unrecognized cranial material associated with the latter specimen; we transfer this species to Eoconstrictor based on cranial features and recombine it as Eoconstrictorspinifer comb. nov. We finally describe much new vertebral and cranial material of Phosphoroboafilholii comb. nov. from the Phosphorites du Quercy (both from the old collections but also from the late Eocene localities of Escamps A and C), paying special attention to intracolumnar variation. Based on this cranial material from Escamps, we identify Phosphoroboa gen. nov. as a booid. An analytical approach is undertaken in many isolated remains in order to quantify vertebral structures and assess intracolumnar variation, as well as associating isolated cranial elements to vertebral-based taxa. 3D models of the type material of the Geiseltal and Messel taxa are presented. The importance of vertebrae in the taxonomy of fossil Constrictores is addressed, although it is acknowledged that it is cranial material that can afford the most reliable phylogenetic conclusions. The diversity, distribution, biogeographic origins, and final demise and extinction of large Constrictores in the Paleogene of Europe are discussed.

New fossil remains from Bang Mark locality, Krabi Basin, southern Thailand

ABSTRACT We describe several mammal taxa from the poorly known late Eocene locality of Bang Mark, Krabi Basin in southern Thailand. Most of them were unknown in that locality that now includes 19 distinct taxa. The new material corresponds to dental remains that can be attributed to a carnivoran, a dichobunid, ruminants, anthracotheres and perissodactyls. These remains provide information on the affinities of several genera that were uncertain so far. Archaeotragulus might be more closely related to Siamotragulus from the Miocene of Southeast Asia, Pakistan and East Africa, and the tragulid status of Krabitherium is supported by the morphology of its p4. We also describe the smallest known anthracothere, Geniokeryx nanus, sp. nov., and a new species of eomoropid chalicothere, Eomoropus meridiorientalis, sp. nov., that represents the first record of that family in the Krabi fauna. This work also supports the contemporaneity of Bang Mark with Wai Lek and Bang Pu Dam.

Cenogram analyses as habitat indicators for Paleogene–Neogene mammalian communities across the globe, with an emphasis on the early Eocene Cambay Shale mammalian community from India

The present study is an attempt to utilize cenogram methodology (both qualitative and quantitative) to consider mammalian communities from five early to late Eocene localities across the globe (i.e., Polecat Bench, Bighorn Basin, North America; Abbey Wood, Blackheath Formation, UK; Cambay Shale, Cambay Basin, India; Wutu Formation, Wutu Basin, China; Pondaung Formation, Myanmar) so as to provide a comparative palaeohabitat framework. It is also a first attempt to examine the palaeohabitat of an extinct mammalian community (i.e., from Cambay Shale) in India utilizing the cenogram approach. In addition, seven extinct middle-Miocene communities (Laogou, Linxia Basin, China; Estacion Imperial, Spain; Paseo de las Acacias, Spain; Arroyo del Olivar-Puente de Vallecas, Spain; Somo-saguas, Spain; Paracuellos 5, Spain; Paracuellos 3, Spain) have also been considered, in order to provide a global perspective to the climatic inferences in a temporal context. The majority of statistical calculations for Paleogene communities expose forested and humid conditions, excluding the Cambay Shale mammalian community of India. A hidden diversity within the medium to large body-size category of mammals (disguising the mammal biodiversity expected in tropical forested habitats) from Cambay Shale (western India) is a plausible cause of digression in the results. This is reflected in the histograms showing relationships between proportions of mammal species in various body-mass categories. Furthermore, the results show that Neogene mammalian communities were sustained in comparatively open habitats. Differences between occidental European and Asian localities in the canopy and humidity of the Neogene environments are also reflected in our analyses.

The rodents from Santpedor-2 (Ebro Basin, NE Spain) confirm the Oligocene age of the latest primates from the Paleogene of Europe

This paper provides a revised and updated description and identification of the rodents from Santpedor-2 (northeastern Spain). The age of this locality is particularly relevant, because it is one of the few European sites assigned to the early Oligocene that has yielded primate remains. However, the rodent assemblage from this site has never been described in detail, and therefore the Oligocene age of this locality remained tentative. Despite the scarcity of the material, the rodents from Santpedor-2 are characteristic enough either to be identified as already known species, or at least compared with close species. Eight different rodent taxa were recognized. Among them, the theridomyid Ectropomys exiguus, which is recorded only in late Eocene localities, and the glirid Glamys devoogdi, which is known in both latest Eocene and early Oligocene localities. The other taxa are found only in Oligocene localities, and consist of the theridomyid Paratheridomys margaritae and members of two families that arrived in Europe at the beginning of the Oligocene: eomyids (Eomys sp.) and cricetids (Eucricetodon atavus, cf. Heterocricetodon sp., cf. Pseudocricetodon sp.). Finally, another theridomyid (Issiodoromyinae) seems to correspond to a new species and new genus, the main features of which correspond to early Oligocene evolutionary grades. This rodent assemblage from Santpedor-2 is assigned to the early Oligocene, mainly on the basis of the presence of immigrant rodents that reached Europe in relation with the Grande Coupure (cricetids and eomyids). This dating is notably supported by the presence of P. margaritae together with Glamys devoogdi, both being found in Hoogbutsel (early Rupelian, MP21). Only one rodent (E. exiguus) represents an Eocene relict, as is the case of Pseudoloris, the only primate recorded in this locality. Therefore, this study supports the Oligocene age of Santpedor-2 and then the persistence of omomyid primates in the Iberian Peninsula (at least locally) after the Grande Coupure.

Pappocricetodontinae (Rodentia, Muridae) from the Paleogene of south-east Serbia

Two species of Witenia and a new pappocricetodontine genus and species from the late Eocene and early Oligocene of south-east Serbia are described. The Pappocricetodontinae a subfamily originally based on the small Pappocricetodon rencunensis from China has become a polyphyletic entity due to inclusion of the genus Witenia. The dental morphology of the late Eocene Witenia europea nov. sp. is very similar to that of the middle Eocene Pappocricetodon antiquus, but its molar enamel is more primitive. The small Bustrania dissimile nov. gen. nov. sp., the dominant species in the late Eocene locality of Buštranje, is defined and allocated to the Pappocricetodontinae.

The primate remains from Roc de Santa (Late Eocene, NE Spain) revisited: New taxonomic allocation

The scarce primate remains from the late Eocene locality of Roc de Santa (Central Pyrenees, NE Spain) were first documented in 1975. This material included a mandibular fragment with P3-M2 and a maxillary fragment with P3-M3 assigned to Adapis magnus (later transferred to the genus Leptadapis), and an isolated M3 attributed to Necrolemur antiquus. However, these specimens were never described in detail. We have thoroughly studied these specimens, with the exception of the mandibular fragment, which has been lost. The maxillary fragment is much smaller than in Leptadapis magnus and shows clear morphological differences from that species; this specimen is assigned to Microchoerus hookeri. Similarly, the isolated M3 resembles that of M. hookeri in size and morphology, and can therefore be attributed to this taxon. In addition, we describe an upper incisor never reported previously, which can also be allocated to M. hookeri, representing the first description of this tooth for the species. Therefore, we conclude that the previous taxonomic determinations were mistaken and all the available primate specimens from Roc de Santa can be confidently assigned to the species M. hookeri, previously described from the same-age localities of Sossís, Spain, and Eclépens-B, Switzerland.

Paracricetodontinae (Mammalia, Rodentia) from the late Eocene and early Oligocene of south-east Serbia

Three Paracricetodon species from the late Eocene locality Buštranje and the Early Oligocene localities Valniš, Strelac-1, -2, -3 and Raljin (south-east Serbia) are described; Paracricetodon dehmi Hrubesch, 1957 and two new species: Paracricetodon stojanovici and P. gracilis. A review of Paracricetodon species suggests that the species P. spectabilis, P. cadurcensis, P. dehmi, P. walgeri and P. wentgesi are primarily distinct in size. Paracricetodon kavakderensis and P. kodjayarmensis from Turkish Trace are considered junior synonyms of P. dehmi. The diversity and abundance of the Paracricetodontinae in the rodent assemblages from Serbia is not known from elsewhere and suggest that they underwent a radiation on the Serbian-Macedonian land area.

New giant penguin bones from Antarctica: Systematic and paleobiological significance

A tarsometatarsus and a fragmented humerus of striking dimensions recently collected in the Late Eocene locality DPV 13/84 Submeseta Formation-level 38 Submeseta II-, Seymour (Marambio) Island, Antarctic Peninsula were both assigned to Palaeeudyptes klekowskii. According to estimates, the tarsometatarsus would belong to the largest and most massive penguin described so far. This bird was probably a piscivorous penguin, with high diving ability for catching prey. Although the humerus is not an appropriate element for body mass or body length assessments, it also belonged to a huge penguin.

A New Miniaturized Lizard From the Late Eocene of France and Spain

We report here a new lizard genus and species shared by two late Eocene localities situated at both versants of the present Pyrenees (South-Western Europe), one located in France (Escamps, MP19), and the other in Catalonia, Spain (Sossís, MP17a). The recovered specimens are remarkable because of their small size and peculiar morphology. Features of the dentary are interpreted as adaptations to a fossorial or semi-fossorial lifestyle, although such modifications obscure the exact phylogenetic relationships of the new taxon. We suggest that it might represent a further example of scincoid lizard that independently achieved adaptations for burrowing or surface-dwelling. This taxon reinforces the hypotheses that link the Southern Pyrenean assemblages to those from France rather than to those of the rest of the Iberian Peninsula, which are supposed to be somehow isolated and endemic to a certain degree during the middle and late Eocene, forming part of the so-called Western Iberian Bioprovince.

Discovery of an embrithopod mammal (Arsinoitherium?) in the late Eocene of Tunisia

Dental and postcranial remains (an atlas, carpus and metacarpus elements, and a part of the pelvic girdle) of an embrithopod mammal are described from Bir Om Ali, Tunisia, a new late Eocene locality. The enamel microstructure of a tooth fragment found in association shows ‘arsinoitheriid radial enamel’, an enamel condition which is characteristic of Arsinoitherium (Arsinoitheriidae, Embrithopoda). Although the postcranial elements slightly differ in size and morphology from those of Arsinoitherium zitteli (late Eocene to early Oligocene), we tentatively refer this new Eocene Tunisian material to that genus. These fossils represent the first known embrithopod from the Eocene of Tunisia.

Nievesia sossisensis, a new anchomomyin (Adapiformes, Primates) from the early Late Eocene of the southern Pyrenees (Catalonia, Spain)

A new genus and species attributed to the tribe Anchomomyini is described from the early Late Eocene locality of Sossís (MP17a), one of the most important Paleogene fossil sites from the Iberian Peninsula. Nievesia sossisensis is characterized by its buccolingually compressed P4 and its upper molars with no pericone, medium-sized hypocone, straight postcingulum and minuscule mesostyle, and the extremely reduced metacone on the M3. Its lower dentition presents a P4 with an incipient metaconid, lower molars with no paraconid and a premetacristid closing the trigonid basin, and M3 with the trigonid wider than the talonid. Phylogenetic analyses suggest a close relationship between Nievesia and Mazateronodon, although the new genus is also related to Anchomomys and, to a lesser extent, Buxella and Periconodon. These analyses, which also include djebelemurines, no longer relate European anchomomyins with crown strepsirhines, and suggest their closer relationship with asiadapines and sivaladapids.

New stem elephant‐shrews (Mammalia, Macroscelidea) from the Eocene of Dur At‐Talah, Libya

Abstract: Two new primitive macroscelideans, Eotmantsoius perseverans gen. et sp. nov. and Nementchatherium rathbuni sp. nov. from the late Middle or Late Eocene locality of Dur At‐Talah, Libya, are described. Eotmantsoius is known from a single tooth and is characterized by low crown height, isolated conules, and lack of a preprotocrista and prehypocrista. Based on these characters, it appears to be more plesiomorphic than Chambius (late Early Eocene, Chambi, Tunisia), which was, to date, universally accepted as the oldest and most basal macroscelidean. Eotmantsoius appears, however, somewhat derived in having an entostyle, a pericone, a shorter mesial cingulum and larger intercusp valleys. The phylogenetic position of Eotmantsoius is unclear. The second new species, N. rathbuni, allows a reassessment of Nementchatherium. We suggest that it is the most derived of the herodotiines in having long preprotocrista and prehypocrista, reduced M2/m2, a robust entostyle twinned with the hypocone on M1 and the posterior aspect of the root of the maxillary jugal process placed along the length of M2. Nementchatherium rathbuni appears more derived than N. senarhense, from the Eocene locality of Bir El Ater, Algeria, in having smaller m2‐3 with no paraconid, a smaller hypoconulid on m2 and a more reduced talonid on m3 (with smaller hypoconid and entoconid). Nementchatherium rathbuni also has, distal to the m3, a coronoid canal. This character has commonly been proposed as a synapomorphy for paenungulates (e.g. proboscideans, sirenians and hyracoids); we investigate the possibility that it unites macroscelideans and paenungulates, as the superordinal clade Afrotheria suggests. Comparisons reveal that a coronoid canal also occurs in several nonafrotherian orders (lagomorphs, xenarthrans, artiodactyls and perissodactyls), suggesting that is not an exclusive synapomorphy for paenungulates plus macroscelideans. Moreover, the homology of the character within paenungulates is doubtful.

New remains ofEgatochoerus jaegeri(Mammalia, Suoidea) from the late Eocene of Peninsular Thailand

Abstract: We report here additional remains referred toEgatochoerus jaegerifrom the late Eocene locality of Ban Mark in the Krabi basin, Thailand. The new material described, comprising upper and lower cheek teeth, deciduous premolars and partial cranial remains, makesE. jaegerithe best‐documented Eocene representative of Old World Suoidea at present. Detailed study and comparison of their cheek teeth structure reveal a homogeneity of the molar crest and groove patterns of Old World and New World Palaeogene suoids.

A new species ofDiplocynodon(Crocodylia, Alligatoroidea) from the Late Eocene of the Massif Central, France, and the evolution of the genus in the climatic context of the Late Palaeogene

AbstractThe genusDiplocynodonis widely recorded in Europe from Early Eocene up to Middle Miocene times. A fragmented but almost complete skull of a new species ofDiplocynodonis reported from the Late Eocene locality of Domérat, northern border of the Massif Central (Allier), France. The present skull provides an important basis for comparison with other members of the genus and complements a fossil record full of gaps despite the large number of vertebrate localities spanning the Cenozoic. The new taxon occurs at a key period for climate evolution with conditions marking the transition from a greenhouse to an icehouse world. The response of crocodylian assemblages to this climatic shift is discussed in light of evidence for their decline in diversity from the Eocene period onward.

A NEW SPECIES OF MOERITHERIUM (PROBOSCIDEA, MAMMALIA) FROM THE EOCENE OF ALGERIA: NEW PERSPECTIVES ON THE ANCESTRAL MORPHOTYPE OF THE GENUS

Abstract: A new species of Moeritherium (Proboscidea, Mammalia), M. chehbeurameuri sp. nov., is described from remains discovered in the early late Eocene locality of Bir El Ater, Algeria. Although mainly represented by isolated teeth, it shows distinct synapomorphies which justify its attribution to the genus Moeritherium, together with exclusive features that led to the creation of the new species. The main characteristic of this new taxon is the almost complete lophodonty shown by its molars, while Moeritherium is commonly regarded as a bunolophodont to bunodont taxon. In addition to this lophodonty, this new taxon shows anatomical features as yet unknown for the genus, but often met within lophodont early proboscidean taxa such as Phosphatherium escuilliei and Numidotherium koholense. Although a revision of the whole genus Moeritherium is outside the scope of this paper, the main controversies and discussion about the definition of species within the genus Moeritherium are discussed. The surprising lophodonty of M. chehbeurameuri, together with its small size, its early late Eocene age and the weak molarization of its P3 support the hypothesis of a lophodont hypothetical ancestor for moeritheres, and therefore strengthen the growing hypothesis of a lophodont dental ancestral morphotype for proboscideans.

Podocarpoxylon helmstedtianumGottwald from Kučlín (Late Eocene, Czech Republic) reinterpreted as Tetraclinoxylon vulcanensePrivé

AbstractA big silicified trunk from the Late Eocene locality of Kučlín was originally identified as Podocarpoxylon helmstedtianum Gottwald and preliminarily associated with co‐occurring twigs and cone scales of Doliostrobus taxiformis (Sternb.) Z.Kvaček. However, the new diagnosis of the genus Doliostrobus, recently complemented by the characteristics of secondary wood of twigs, does not support such an attribution. On the basis of a new analysis of wood structures and comparisons, the fossil wood from Kučlín is reinterpreted as Tetraclinoxylon vulcanense Privé, and associated with twigs and seeds of Tetraclinis salicornioides (Unger) Z. Kvaček, the second conifer recorded at this locality.

A new Late Eocene anthropoid primate from Thailand.

The fossil record of anthropoid primates from the Middle Eocene of South Asia is so far restricted to two genera (Pondaungia cotteri Pilgrim, 1937 and Amphipithecus mogaungensis Colbert, 1937 from the Eocene Pondaung deposits of Burma) whose anthropoid status and phylogenetic position have long been under debate because they represent the oldest highly derived fossil primates of anthropoid grade. Moreover, several new African taxa, some of which are even older, have been recently included in the suborder Anthropoidea, suggesting an African origin for this group. Conversely, new fossil primates recently discovered in China (Eosimias) have been related to the most primitive representatives of Anthropoidea, alternatively suggesting an Asian origin and a probable Asian radiation centre. We report here the discovery of a new anthropoid from the Thai Late Eocene locality of Krabi, which displays several additional anthropoid characters with regard to those of the Eocene Burmese genera. This species, which is about the size of the Fayum Aegyptopithecus, can be related to the Burmese forms, and it further provides strong additional evidence for a southeast Asian evolutionary centre for anthropoids.