Presence of the large aquatic snake Palaeophis africanus in the middle Eocene marine margin of the Congo Basin,Cabinda, Angola

Ten isolated snake vertebrae from Landana and Sassa-Zao, Cabinda Exclave, Angola, present a “primitive” grade morphology with a weak lateral compression and do not belong to Palaeophis aff. typhaeus as originally referred to. They well belong to a single taxon and are here attributed to Palaeophis africanus for which the intracolumnar variation is described and illustrated. This species is Lutetian (middle Eocene) in age and originates from a marine coastal environment confirming again the aquatic capabilities of palaeophiid snakes. It represents the third largest species of Palaeophis with P. colossaeus and P. maghrebianus to which it is closely related in our tentative phylogenetic analysis, indicating that these three taxa could belong to an African clade. This study also contributes to the debate on the existence of primitive and advanced grades among palaeophiid snakes. Palaeophis presents laterally compressed anterior trunk vertebrae that could have been often erroneously considered as representing advanced grade species and potential parataxonomy.     

A new seabird (Aves, cf. Phaethontidae) from the Lower Eocene phosphates of Morocco

A proximal part of humerus from the basal Ypresian (lowermost Eocene) of the Ouled Abdoun Basin, Morocco, is described as a new genus and species tentatively assigned to the Phaethontidae (tropicbirds). This fossil possibly represents the oldest record of the Phaethontidae and markedly differs from Lithoptila, a contemporaneous Prophaethontidae from the same locality. This new taxon lived in a tropical climate and was probably an efficient flier with pelagic habits, like extant tropicbirds of the genus Phaethon.     

New proviverrines (Hyaenodontida) from the early Eocene of Europe; phylogeny and ecological evolution of the Proviverrinae

We describe six proviverrine species from the Early Eocene of France. Three species are new: M inimovellentodon russelli sp. nov. from Mutigny [mammal palaeogene (MP)8 + 9], B oritia duffaudi sp. nov. from La Borie (MP8 + 9), and L eonhardtina godinoti sp. nov. from Grauves (MP10). We describe new specimens and propose new generic combinations for three species from MP10: Protoproviverra palaeonictides, Matthodon menui, and Oxyaenoides lindgreni. We also propose a new generic combination for the primitive Eoproviverra eisenmanni (MP7). Matthodon menui was previously considered as a possible oxyaenodontan, but the new fossils clearly support its reference to Hyaenodontida. Leonhardtina godinoti and Ma. menui are the oldest occurrences for these genera, which were previously unknown before the Middle Eocene. Moreover, the discovery of the proviverrine Mi. russelli in Mutigny implies that the Proviverrinae dispersed in Northern Europe between biozone Palaeocene‐Eocene (PE) III (Abbey Wood) and biozone PE IV (Mutigny). This also supports a homogenization of the European faunas during the Early Eocene. The dispersal is concomitant with the disappearance of the oxyaenodontans, arfiines, and sinopines (Hyaenodontida) from Europe. The proviverrines may have filled the ecological niches left vacant by the disappearance of the other carnivorous mammals. With 20 genera and over 30 species, proviverrines were successful in Europe. We performed the first phylogenetic analysis comprising almost all the Proviverrinae. Our analyses indicate that the Proviverrinae diversified greatly during the Early Eocene Climatic Optimum and show a general trend towards specialization throughout the Eocene. © 2014 The Linnean Society of London     

Vertebrae of the sea snake <Emphasis Type="Italic">Palaeophis nessovi</Emphasis> Averianov (Acrochordoidea,Palaeophiidae) from the Eocene of western Kazakhstan and phylogenetic analysis of the superfamily Acrochordoidea

The vertebrae of sea snakes from five Eocene localities in western Kazakhstan are assigned to the species Palaeophis nessovi Averianov, 1997. The anterior trunk vertebrae have subcentral ridges, large posterior hypapophysis, and large synapophyses; the middle trunk vertebrae are slightly laterally compressed and their synapophyses are positioned highly; the posterior trunk vertebrae are strongly laterally compressed and have a well-developed haemal keel. Cladistic analysis has shown that the genus Palaeophis is not monophyletic; the genus Archaeophis is a more advanced palaeophiid than was previously thought.     

A new species of Neochelys (Chelonii,Podocnemididae) from the Ypresian (Early Eocene) of the South of France

The known European record of the Gondwanan group Podocnemididae begins in the Early Eocene. Neochelys underwent a rapid diversification and was an abundant and diverse representative of this group during the Eocene of Europe from the Early Ypresian to at least the Bartonian. However, several of its species are poorly known, and the phylogenetic relationships among them are poorly understood. A complete shell from the Ypresian of Hérault (southern France) is described here. It is assigned to a new species, Neochelys liriae. The availability of characters of N. liriae is tested by comparison with the other European species, which appear to be well differentiated, and particularly with the neighbouring French taxa N. eocaenica and N. laurenti, of which the latter has been little known to this point.     

Redescription, palaeobiogeography and palaeoecology of Coniasaurus crassidens Owen, 1850 (Squamata) from the Lower Chalk (Cretaceous; Cenomanian) of SE England

Type and referred specimens of Coniasaurus crassidens from the Lower Chalk (Upper Cretaceous; Cenomanian) of southeast England, are re-described. The type is a left maxilla associated with 14 dorsal vertebrae. The maxilla is elongate, bears a low ascending process, and has a long and posteriorly positioned external narial margin. The first maxillary tooth is pointed and bears a groove on the labial face; more posterior maxillary teeth are increasingly rounded and bulbous, and have a single groove on the labial face. Mandibles assigned to Coniasaurus cf. C. crassidens possess teeth of similar form; mandibular bones include the dentary, splenial, angular, coronoid, prearticular, and surangular. A number of features show important similarities to later mosasaurs and contemporaneous groups such as dolichosaurs. These new data provide a very different picture of coniasaurs and their mode of life in the early Upper Cretaceous. The functional morphology of coniasaur teeth is unique and shows occlusion between the lingual platforms of the upper teeth with the crowns of the lower teeth. Coniasaurs can be considered as analgous to small sauropterygians in terms of general morphology, habitats, and trophic structure. Coniasaur distributions in the Cenomanian and Turonian of Europe and North America are similar to the palaeobiogeographic patterns of other organisms living in the Tethys and SuperTethys Seaway.     

BROMALITES FROM THE SOOM SHALE LAGERSTÄTTE (UPPER ORDOVICIAN) OF SOUTH AFRICA: PALAEOECOLOGICAL AND PALAEOBIOLOGICAL IMPLICATIONS

Abstract:  Bromalites from the Soom Shale are allocated to five main categories on the basis of shape, content and internal structure: those containing broken conodont elements; those containing brachiopod fragments; corrugated/spiral forms; coiled coprolites and wrinkled coprolites. It is impossible to allocate specific bromalites to the organisms that formed them, but the occurrence of crushed discinoid valves in several specimens demonstrates that an effective durophagous predator was present in the Soom Shale community. The presence of fragmented elements of conodonts in other specimens provides direct evidence of tiering within the predatory trophic level in the Soom Shale. Conodonts, other agnathan vertebrates, orthoconic cephalopods and eurypterids are all possible contenders for producing most of the bromalites recorded, but there may have been unrecorded large predators in the community.     

An enigmatic actinopterygian (Pisces: Osteichthyes) from the Upper Permian of China

A new actinopterygian fish Yaomoshania minutosquama gen. & sp. nov., from the Upper Permian of the Dzungaria [Junggar] Basin in China is described. The material consists of two very fragmentary specimens showing almost exclusively scale rows. The arrangement of the scale rows of the holotype resembles the reversion lines of acanthodian caudal fins and of cheirolepids. The size and shape of the scales, and the diminishing size of the scales along the rows, is similar to those of acanthodians and those actinopterygians with small scales such as Cheirolepis. However, the histology of the scales demonstrates features that are found in more advanced actinopterygians: superimposed ganoine lamellae, the arrangement of dentine tubules and pulp canals, buried odontodes stacked on each other to make the ornamental ridges, and an asymmetric pattern of growth achieved by extensive remodelling (resorption and redeposition) of all layers of the scale. Yaomoshania minutosquama is proposed as a small-scale bearing, basal actinopterygian, different from Cheirolepis , but characterized by advanced histological characters.     

Recovery dynamics of benthic marine communities from the Lower Triassic Werfen Formation,northern Italy

The Lower Triassic Werfen Formation of northern Italy represents an important archive for Early Triassic ecosystems. Based on quantitative community analysis using species level identifications, we reconstruct the recovery of benthic ecosystems after the end‐Permian mass extinction throughout this unit. The analysis of benthic macrofossil communities shows that incipient recovery has taken place during the Griesbachian and the Griesbachian–Dienerian transition. A probable deterioration in environmental conditions is observed towards the end of the Dienerian. The Smithian part of the Werfen Formation is characterized by high siliciclastic input, which ceases around the Smithian‐Spathian boundary. The Spathian marks the definitive phase of recovery in the Werfen Formation. The comparison of this pattern with other palaoegeographical regions suggests that both the Griesbachian recovery and the Dienerian decline were of inter‐regional if not global extent, whereas the Smithian diversity low in the Werfen Formation is a local signal. In contrast to the recovery dynamics of ammonoids and conodonts, the Smithian–Spathian boundary interval was no caesura for benthic ecosystems. The Spathian recovery pulse is possibly also an inter‐regional event, at least in the palaeotropics. These results are in contrast with the previously proposed scenario of persistent hostile conditions during the Griesbachian time interval and highlight an initial recovery phase restricted to Griesbachian times. Instead, the apparently sluggish recovery of benthic ecosystems was at least partly shaped by set‐backs due to short‐term environmental perturbations during the Dienerian.     

Evenness and diversity in Upper Cambrian – Lower Ordovician trilobite communities from the Central Andean Basin (Cordillera Oriental,Argentina)

Community evenness has recently received much attention, either because it is related to ecosystem functioning or because it may affect estimation of diversity. Temporal and environmental trends in diversity and evenness of trilobite communities during the Late Cambrian – Early Ordovician of the Cordillera Oriental (north‐western Argentina) are here analysed. Richness and evenness increase through time in both deep subtidal (between fair‐weather and storm wave base) and offshore (below storm wave base) communities. Two significant patterns are superimposed on this general trend: (1) the magnitude of the increase in evenness is much more pronounced in deep than in shallower settings, and (2) richness and evenness trajectories are decoupled (while a significant rise in evenness is recorded in the middle Tremadocian (Tr2), an increase in richness is delayed until the late Tremadocian (Tr3)). In contrast to expectations, a single family (Olenidae) is dominant in samples associated with this earlier rise in evenness relative to richness. Hence, this trend is explained neither by the number of families present in the communities nor by the familial identity of the most abundant taxon. Large‐scale comparisons of the timing and geographical components of these trends are restricted to the patterns recognized in Laurentian North American studies. Results from the Cordillera Oriental mirror those of Laurentia regarding the rise in both metrics in deep marine settings. Nevertheless, the timing of this increase in richness and evenness is delayed in the Cordillera Oriental, supporting the idea that palaeogeographical regions differed in the nature and timing of ecological changes. Finally, the rise in trilobite alpha‐diversity through the Late Cambrian – Early Ordovician of the Cordillera Oriental supports the idea that trilobite alpha‐diversity did not decline worldwide, suggesting that the relative decline in trilobite alpha‐diversity is most probably caused by the dilution effect.     

A new psittaciform bird from the London Clay (Lower Eocene) of England

A new psittaciform bird from the Lower Eocene (Ypresian) London Clay of England is described. This taxon, Pulchrapollia gracilis gen. et sp. nov., is assigned to the order Psittaciformes (parrots) on the basis of several distinctive structures of the tarsometatarsus, namely the trochlea for metatarsal III (trochlea metatarsi III) bearing a tubercle on its lateral side and the trochlea for metatarsal IV (trochlea metatarsi IV) completely retroverted (fully zygodactyl foot). Comparisons with other fossil and Recent taxa further support this conclusion. Cladistic analysis shows that Pulchrapollia is the sister-taxon of the single extant family within Psittaciformes, the Psittacidae. Palaeopsittacus georgei, a taxon previously described from the London Clay, is most likely based on some unassociated material and is regarded here as incertae sedis.     

New hyaenodonta (Mammalia) from the middle Eocene of Myanmar

The middle Eocene Pondaung Formation in Myanmar has yielded a rich mammalian fauna including several Primate taxa. Hyaenodonta are known by the genera Kyawdawia, Yarshea, Orienspterodon, and two other indeterminate taxa. We describe here new material of Kyawdawia, including some morphological details, a new species of the hypercarnivorous genus Propterodon and an indeterminate species, different from those described earlier in Myanmar, and characterized by a reduction of m3 and would belong to a third lineage with the same evolutionary trend as Galecyon and the Limnocyoninae. The hyainailourines (Orienspterodon) and hyaenodontines (Propterodon) are recorded for the first time in Southeast Asia and these subfamilies appeared in quasi the same time in Europe illustrating probably a profound change in the carnivorous fauna among Laurasia.     

New marine mammal faunas (Cetacea and Sirenia) and sea level change in the Samlat Formation,Upper Eocene,near Ad-Dakhla in southwestern Morocco

The Samlat Formation is well exposed in coastal sections bordering the Atlantic Ocean south of Ad-Dakhla in southwestern Morocco. Here some 22 m of rhythmically-bedded, chert-rich, marine siltstones and marls are overlain by 1–1.5 m of vertebrate-bearing microconglomeratic sandstone, another 4–8 m of rhythmically-bedded siltstone and marl, and finally a second 3–6 m unit of vertebrate-bearing muddy sandstone. The microconglomeratic and muddy sandstones represent low sea stands in what is otherwise a deeper water sequence. Cetacean skeletons are rare but cetacean vertebrae are common in the lower sandstone (bed B1), where many show the effects of reworking. The cetaceans in bed B1represent a minimum of five species, from smallest to largest: cf. Saghacetus sp., cf. Stromerius sp., Dorudon atrox, cf. Dorudon sp., and Basilosaurus isis. Bed B1 yields rib fragments that may represent sirenians, but sirenians, if present, are rare. The only identifiable cetacean found in the upper sandstone (bed B2) is Basilosaurus sp. Dugongid sirenians identified as cf. Eosiren sp. are the most common mammal in bed B2. We interpret co-occurrence of the typically Early Priabonian species Dorudon atrox and Basilosaurus isis with smaller species more like Middle Priabonian genera Saghacetus osiris and Stromerius nidensis to indicate that bed B1 was deposited during low sea stand Pr-2 between the Early and Middle Priabonian (between the early and middle Late Eocene). Bed B2 is separated from B1 by an interval of deeper water sediment accumulation. Bed B2 could represent a later phase of Pr-2 or a subsequent Priabonian low sea stand (possibly Pr-3).     

Coprolites from shallow marine deposits of the Nanjemoy Formation,Lower Eocene of Virginia,USA

The Eocene Nanjemoy Formation crops out on the Maryland and Virginia Coastal Plain, along the eastern coast of the United States. This formation is composed of sands, silts and clays and is divided into the Potapaco and Woodstock members. Remains of fishes, reptiles, birds, mammals, molluscs, fruits and seeds are common in the Potapaco Member, in addition to vertebrate coprolites. Here, we present an analysis of more than 2000 coprolites from the Fisher/Sullivan Site in Virginia. The chemical composition (phosphatic) and the type of inclusions (fish bones) indicate that only scats of carnivorous animals were preserved. The analysed specimens were grouped into six morphotypes: (1) the cylindrical morphotype is a cylinder with rounded ends; (2) the segmented morphotype is a cylinder segmented with rounded ends, and occasionally one end is concave; (3) the oval morphotype represents a bean‐shaped coprolite; (4) the scroll morphotype is cylindrical to conical in lateral view and has coils seen only at the ends; (5) the folded morphotype is a spiral that is concentrically folded; and (6) the sinuous morphotype is serpentine, with rounded ends. Coprophagy‐related scrape traces occur in different morphotypes and represent both invertebrate burrows and bite traces made by fishes. The mineralogical and chemical analyses indicate an early precipitation of phosphate and pyrite minerals, probably induced by the microbial community. All coprolites at the Fisher/Sullivan Site were produced by fishes: carcharhiniform sharks for the scroll morphotype and lamniform sharks, probably the genus Carcharias, for the folded morphotype; the oval, cylindrical and segmented morphotypes were likely produced by actinopterygian fishes.     

Dispersed cuticles from the Eocene of North America

KOVACH, W. L. & DILCHER, D. L., 1984. Dispersed cuticles from the Eocene of North America. Macerations of organic-rich clay from the Claiborne Formation (Middle Eocene) of Tennessee have yielded a wide variety of well-preserved dispersed cuticles. Details of the epidermal cell patterns, arrangement of the stomata1 complex, trichomes and trichome attachment have made possible the association of some dispersed cuticles with leaf types known from this formation which have similar cuticle, and with modern families. All dispersed cuticles are classified in a morphologic system. Through both our own work and a review of previous investigations we have found that distinct dispersed cuticle types can be recognized and may be used biostratigraphically to characterize geologic strata, palaeo-ecologically to provide insights into environmental reconstruction, and systematically to follow the history of certain taxa.     

Filling the North European Early/Middle Eocene (Ypresian/Lutetian) boundary gap: Insights from the Pyrenean continental to deep-marine record

The Early/Middle Eocene (Ypresian/Lutetian) transition is represented by a hiatus in many North European sections, including those in which the classic stratotypes were originally defined. However, the Global Stratotype Section and Point of the Lutetian Stage, which is still pending definition, should be placed at a globally correlatable event included within that unrepresented interval. The Pyrenean Eocene outcrops display sedimentary successions that offer the rare opportunity to analyse the Ypresian/Lutetian boundary interval in almost continuous sections and in very different settings. Seven reference stratigraphic sections were selected on the basis of their quality and correlated by means of biomagnetostratigraphic data. This correlation framework casts light on the sequence of chronostratigraphic events that characterize the Ypresian/Lutetian boundary interval, which may prove useful in defining the main correlation criterion of the base of the Lutetian.All of the Pyrenean sections show a similar sedimentary evolution, despite being up to 350 km apart from each other, containing deposits of different origins (intrabasinal carbonate sediments, siliciclastic sediments sourced from the Iberian plate, and terrigenous sediments sourced from the uplifting Pyrenees) and despite having been accumulated in different sedimentary environments (from continental to deep marine) and in different geodynamic settings (piggy-back basin, foreland basin and cratonic margin). This common evolution can be readily interpreted in terms of a sea-level driven depositional sequence whose lowstand and transgressive systems tracts are included within the Ypresian/Lutetian boundary interval. The Pyrenean Ypresian/Lutetian depositional sequence can reasonably be correlated with depositional sequences from classic North European areas, shedding light on the palaeoenvironmental history which in those areas has not been recorded. Furthermore, these depositional sequences may possibly correlate with others from the Antarctic Ocean and from New Jersey, as well as with oceanic temperature variations, suggesting that they might be the result of climatically-driven glacioeustatic sea-level changes. Should this hypothesis prove correct, it would confirm previous suggestions that the onset of Antarctic glaciations needs to be backshifted to the late Ypresian at least.     

Diversity and palaeoecology of the enigmatic genus Knebelia (Eucrustacea,Decapoda, Eryonidae) from Upper Jurassic plattenkalks in southern Germany

For a long time, the genus Knebelia Van Straelen, 1922 has comprised two species of eryonid lobster, K. bilobata (Münster, 1839) and K. schuberti (Meyer, 1836), both recorded exclusively from Late Jurassic Lagerstätten in southern Germany. Recently, the latter has been suggested to represent a juvenile individual of Cycleryon propinquus (Schlotheim, 1822). A re‐examination of the type and new material has led to our rejection of that interpretation and confirmation of assignment of this species to Knebelia. Two specimens, both possessing short frontal lobes, from plattenkalks at Nusplingen (late Kimmeridgian) and at Solnhofen (early Tithonian), respectively, are here assigned to a new species, K. totoroi sp. nov. This new species and a review of K. bilobata have furnished new insights into the origin and function of the frontal lobes, which are expansions articulated to the front of the carapace. They probably functioned as rudders facilitating ‘tail‐flip swimming’ as observed in the paddle‐like antennae of extant scyllarids (Eucrustacea, Decapoda, Scyllaridae). The rudder‐like lobes identified in Knebelia may therefore represent a case of convergent evolution.