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Paleocene and Eocene bird assemblage from the Southern North Sea Basin
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Numerous bird bones from the Paleocene and early Eocene of the Belgian and Paris basins have been collected by amateur paleontologists. Four bones from the early-middle Selandian of Maret, Belgium are among the earliest Cenozoic avian remains from Europe and include the oldest temporally well constrained records of the Gastornithidae, as well as tentative records of the paleognathous Lithornithidae and the Ralloidea. Another assemblage from the middle Thanetian of Templeuve, France contains multiple bones of the Lithornithidae as well as a record of the Pelagornithidae. Specimens from the latest Thanetian of Rivecourt-Petit Pâtis, France are tentatively assigned to the Ralloidea and Leptosomiformes. An assemblage of 54 bones from the middle Ypresian of Egem, Belgium represents at least 20 species in more than 11 higher-level taxa. Well-identifiable specimens are assigned to the Odontopterygiformes, Galliformes, Messelornithidae, Apodiformes, Halcyornithidae, Leptosomiformes, and Coraciiformes. Further specimens are tentatively referred to the phaethontiform Prophaethontidae and to the Accipitridae, Masillaraptoridae, and Alcediniformes. These three-dimensionally preserved fossils provide new data on the osteology of taxa that are otherwise mainly known from compression fossils with crushed bones. They also further knowledge of the composition of early Paleogene avifaunas of the North Sea Basin. Paleocene avifaunas of Europe and North America appear to have had different compositions and only a few taxa, such as the paleognathous Lithornithidae, are known from both continents. This suggests that the very similar early Eocene avifaunas of Europe and North America are the result of early Cenozoic dispersal events. The well-represented small galliform species from Egem most closely resembles Argillipes aurorum, an ignored galliform species from the London Clay. The tentatively identified fossils of Accipitridae and Alcediniformes would represent the earliest fossil records of these clades. The birds from Egem include few seabirds (Odontopterygiformes, cf. Prophaethontidae) and is dominated by terrestrial species (Galliformes, Messelornithidae). Arboreal birds (Halcyornithidae, Leptosomiformes, cf. Alcediniformes, Coraciiformes) are less abundant and aerial insectivores (Apodiformes) very scarce, which either indicates a taphonomic bias in the composition of the avifauna or particular paleoenvironmental characteristics of the nearshore habitats in that area of the southern North Sea Basin. Grant Information: Funded by Belgian Science Policy Office (project BR/121/A3/PalEurAfrica).
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RBINS Staff Publications 2019
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Critical analysis of the carnivoran mammal success in Europe during the Paleogene
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Why are we surrounded by only one group of placental carnivorous mammals (Carnivora: the presentday lions, dogs, bears, and seals among others) today, while at least three other groups of placental mammals (Hyaenodonta, Mesonychia, Oxyaenidae) were in competition with carnivorans 50 million years ago? Since the 1990s, palaeontologists have investigated the success of carnivoraform mammals (including Carnivora) and their crucial adaptations in detail. Analysis of the taxonomic and morphological diversification of these groups in the North American fossil record clearly demonstrated that carnivoraforms outcompeted hyaenodonts and oxyaenids during the Eocene, specifically from around 50 Ma onwards. We document the evolutionary history of the taxonomic diversity as well as the evolution of the body mass of carnivorous mammals that lived in Europe during the Paleogene (66–23 Ma). The results suggest that this competition was diametrically opposed in North America and Europe. Carnivoraforms actually did not become diversified in Europe during the Eocene and thus were not as taxonomically successful in Europe as in North America during that period. Moreover, during the Eocene, European hyaenodonts varied more in body mass than carnivoraforms. The situation dramatically changed during the 'Grande Coupure' (around Eocene–Oligocene boundary; ca. 33.9 Ma). This transition corresponds to a major faunal turnover in Europe: during the earliest Oligocene global cooling event (Oi-1), the Eocene endemic carnivorous fauna was replaced by immigrant taxa (hyaenodonts and carnivorans), mainly from Asia. This abstract is a contribution to the Belspo Brain Pioneer project BR/175/PI/CARNAGES funded by the Belgian Science Policy Office.
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RBINS Staff Publications 2019
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Cambaytherium, most primitive known perissodactylamorph (early Eocene of India), and the origin of the mammalian order Perissodactyla
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Cambaytherium is a primitive, perissodactyl-like mammal from the early Eocene Cambay Shale Formation of Gujarat, India, discovered 15 years ago. There are now more than 350 specimens of Cambaytherium, representing almost the entire dentition and skeleton. Its unique combination of plesiomorphic anatomical traits typical of archaic ungulates like phenacodontids, and derived traits that characterize early perissodactyls, offers important new insight into the expected anatomy of the common ancestor of Perissodactyla as well as the geographic center of origin of the order. Cambaytherium was a subcursorial animal better adapted for running than phenacodontids but less specialized than basal perissodactyls. Its cheek teeth are bunodont with large upper molar conules, not lophodont as in early perissodactyls; but as in perissodactyls, the lower molars have twinned metaconids and m3 has an extended hypoconulid lobe. A steep wear gradient with heavy wear in the middle of the tooth-row, and at the bases of the canines, suggests an abrasive herbivorous diet. We recognize three species of Cambaytherium: C. thewissi (~23 kg), C. gracilis (~10 kg), and C. marinus (~99 kg). Body masses were estimated from tooth size and long bone dimensions. Biostratigraphic and isotopic evidence indicate an age of c. 54.5 Ma for the Cambay Shale vertebrate fauna (the oldest continental vertebrate assemblage from India), near or prior to the initial collision with Asia. Cambaytheriidae (also including Nakusia and Perissobune) and Anthracobunidae are sister taxa, composing the clade Anthracobunia, which is the sister group of Perissodactyla. They comprise a new higher taxon, Perissodactylamorpha. Occurrence of its most primitive known member, Cambaytherium, in India suggests that Perissodactyla evolved during the Paleocene either in India or in peripheral areas of southern or southwestern Asia. Where Cambaytherium evolved, and how and when it reached India, remain unresolved. Supported by National Geographic Society, Leakey Foundation, U.S. NSF, Government of India, Wadia Institute of Himalayan Geology, Belgian Science Policy Office, and Alexander von Humboldt Foundation.
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RBINS Staff Publications 2019
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Dinoflagellate cyst biostratigraphical and palaeoecological analysis of the early Paleogene Landana reference section, Cabinda Province, Angola
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Systematic palynological analysis of the Landana section has revealed 90 distinct dinoflagellate cyst taxa and has resulted in the establishment of a novel preliminary dinoflagellate cyst zonation. The zonation comprises three distinct dinoflagellate cyst zones and five unzoned, yet otherwise distinct intervals, spanning the ?Danian/early Selandian to Eocene/early Oligocene. The Landana record, which represents the first extensive sub-equatorial African Paleogene dinoflagellate cyst record, was extensively compared and correlated with contemporaneous records relatively close by in the Gulf of Guinea, as well as with records from more distant locations such as Antarctica, Australia and New Zealand. The ?Danian–Selandian segment of the record is characterized by the presence of taxa such as Alterbidinium? pentaradiatum, Isabelidinium? viborgense, Isabelidinium cingulatum and Spinidinium densispinatum. The Thanetian through Ypresian succession is far more fragmentary and is devoid of any significant marker taxa. The few dinoflagellate cyst-bearing samples in the uppermost part of the record point to an Eocene to early Oligocene age. The dinoflagellate cyst assemblages are very variable, with several dinoflagellate cyst taxa and ecological groups and complexes rising to dominance successively. Overall high TOC values, significant enhancements in %TP and intervals dominated by presumably heterotrophic dinoflagellate cysts, suggest periods of significant palaeoproductivity and nutrient availability resulting from either heightened terrestrial influence or enhanced upwelling. The overall dinoflagellate cyst assemblages concur with the recorded marine vertebrate faunas and the available sedimentological data that point to a coastal/shallow marine setting for the ?Danian–Ypresian succession. This work was supported by the Belgian Science Policy Office under Grant BR/121/A3/PALEURAFRICA.
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RBINS Staff Publications 2019
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The micropreparation of a juvenile marine turtle from the Ypresian of Belgium
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Several years ago, amateur palaeontologist Michel Girardo collected a block of clay (25x20x18cm) encasing a partially visible small turtle shell, at the Durieux brickyard of Ghlin (Mons Basin). The Clay of Ghlin is stratigraphically important because it belongs to the early Ypresian Mont-Heribu Member of the Kortrijk Clay Formation, representing one of the earliest marine, mid-neritic, depositional environments of the Ypresian in the Mons Basin. The fossil itself is 15x9cm and consists of a full carapace with all plates in connection, half of the marginal plates, and a crushed part of the head. The preservation is very good and the bones suffered almost no displacement during or after burial. Unfortunately, after excavation and during decades of storage, the block of clay had dried and shrunk, leading to stress deformation of the fragile thin bones and to pyrite oxidation. Thin coats of Paraloid B-72 glue were applied before any work. The block was carefully reduced using chisels and hammer. The separated chunks of clay were then disaggregated in water and sieved, resulting in the recovery of shark teeth and fish bones. The preparation of the specimen was done almost exclusively under stereomicroscope. Air scribes could not be used, only small carbide needles. Well-preserved long bones from the shoulder girdle were found during the work. The clay's shrinkage permitted to separate completely the carapace from the substrate. A well-preserved plastron was in this way discovered and almost all vertebrae were found to be still attached to the vertebral plates. All this precise and slow work produced a very fine and well-preserved marine juvenile specimen, presenting a maximum of details, much more than could be guessed when the specimen was received. This will be quite helpful for the identification of this specimen and for comparison with typical Belgian Thanetian-Ypresian turtles such as Erquelinnesia, Eochelone and other Pancheloniidae. This work is a contribution to network project BR/121/A3/PALEURAFRICA of the Belgian Science Policy Office.
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RBINS Staff Publications 2019
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High diversity of Raoellidae (Artiodactyla, Mammalia) from the middle Eocene Subathu Group of Kalakot, Northwest Himalaya, India
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The middle Eocene Subathu Group of Kalakot area (northwest Himalaya, India) is well known for its diverse mammalian fauna, especially of raoellid artiodactyls, which are presently represented by four genera: Indohyus, Khirtharia, Kunmunella, and Metkatius. Our recent work on artiodactyls from the Kalakot area recovered several new taxa in addition to earlier known raoellids. The first new taxon is characterized by its small size, higher and more conical lower molar cusps than in Khirtharia and Metkatius; protoconid and metaconid closely appressed; crista obliqua meets at trigonid notch, presence of an hypolophid and a welldeveloped labial cingulid; bunodont upper molars, subrectangular M1-M2, and subtriangular M3, large metaconule (pseudohypocone) and small well distinct paraconule; cristae well distinct, small metastyle on M3 (absent in the four other raoellid genera), slightly inflated anterior and posterior cingulae. The second new taxon is the smallest of all known Raoellidae; it has bunodont lower molars with tiny paraconid in m1-2 (paraconid is absent in all other raoellids) and crista obliqua meeting the labial base of protoconid; m3 with an hypolophid and well-individualized hypoconulid centrally placed and higher than entoconid; M2 subrectangular, protocone higher than metacone, para and metastyle less distinct than in Indohyus and Kunmunella, ectoloph distinct. Besides these two new taxa, Khirtharia dayi known from Pakistan is reported for the first time from India on the basis of its morphology and size of m3. A new species of Metkatius is characterized on the basis of m1-2, which differ from those of M. kashmirensis by the metaconid higher than the protoconid and by being more than 20% larger. Outside the Indian sub-continent, raoellid artiodactyls are also known from the middle Eocene Pondaung Formation of Myanmar and Shanghuang fissure filling of Jiangsu, China. The predominance of the family Raoellidae in Kalakot provides new information about their phylogenetic position and allow to discuss their origin, evolution, and dispersals. This work is partly funded by project BR/121/A3/PALEURAFRICA from the Belgian Science Policy Office.
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RBINS Staff Publications 2019
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Application of long-term chemostratigraphy (organic carbon isotopes) in age calibration of Paleogene mammal faunas
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Rapid, ‘short-term’ (10 kyr to several 102 kyr) δ13C - δ18O excursions on various materials (bulk, pedogenetic nodules, specific foraminiferal taxa, secondary layer of brachiopods, dispersed organic matter, wood fragments) have been used for decades as reliable stratigraphic tools during the Paleogene (Late Danian Event, PETM or ETM-1, ETM-2, ETM-3, MECO, Oi-1, …). ‘Long-term’ δ13C isotope trends (102 kyr to several myr) may also provide new stratigraphic insights, particularly in sections without any detailed stratigraphic information. Here we show and discuss the potential uses, biases, limits, and perspectives of long-term δ13C isotope trends on organics, from vertebrate-bearing sections in Morocco, Southern France (Corbières, Minervois, Montpellier area, Provence), Angola and Belgium. Using long-term carbon isotopes on organic matter, terrestrial sections can be correlated with the marine stratigraphic international record. Inter- and intraregional correlations are proposed on the basis of bio- and chemostratigraphic calibration of the various records, particularly with the well-known and continuous sections of the Bighorn Basin, Wyoming (USA). These correlations may contribute to the age calibration of the Paleogene mammal faunas (including endemic faunas) and may shed new light on their evolution in different parts of the world. This work was partly funded by the Belgian Science Policy Office, project BR/121/A3/PALEURAFRICA.
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Additional vertebral material of Thaumastophis from the early Eocene of India provides new insights on the early diversification of colubroidean snakes
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The Ypresian Cambay Shale Formation at Vastan, Mangrol, and Tadkeshwar lignite mines in Gujarat, western India, has yielded a rich vertebrate fauna including madtsoid, palaeophiid, booid, and colubroid-like snakes. The latter are particularly abundant but their systematic affinities are difficult to resolve. Here we describe new specimens of the colubroidean-like snake Thaumastophis missiaeni, including anterior, mid-, and posterior trunk vertebrae, as well as caudal vertebrae. This species presents several characters shared with Renenutet enmerwer from the late Eocene of Egypt, suggesting exchange with North Africa probably along the southern margin of the Neotethys. Among these are the presence of parazygosphenal foramina (although not in all vertebrae), deep blade-like prezygapophyseal processes, and thick and tall neural spine. The available vertebral evidence is hardly sufficient to distinguish both taxa from each other, suggesting that these might be even congeneric taxa. However, more material is needed to test more appropriately this hypothesis. Both taxa are considered to be close to the root of the Colubroidean tree. We also revise the Eocene colubroidean fossil record in light of these new findings. This research was funded by grants from National Geographic Society, Leakey Foundation, U.S. NSF, Government of India, Wadia Institute of Himalayan Geology, Belgian Science Policy Office, and Brazilian FAPESP.
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RBINS Staff Publications 2019
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The large trionychid turtles from the early Eocene record of Belgium
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Remains of trionychid turtles are abundant in the early Eocene fossil record of Belgium where several species are recognized. In this context, the remains of several large-bodied individuals, with a shell length of about one meter, stand out both for their size and good preservation. The Royal Belgian Institute of Natural Sciences houses several unpublished large-size specimens, but also others with a high historical value (e.g., those from Erquelinnes and Leval), which had not been, until now, studied in detail. Recent studies proposed that all large trionychids from the Eocene of Western Europe could belong to a single species, attributable to the North American genus Axestemys. However, a valid diagnosis for this putative European single species is not currently available, since the characters that allow its differentiation with each of the North American species have not been well established. Several of the best preserved Belgian specimens have been recently restored, which allows us to perform their detailed study. Thus, the description of several anatomical elements hitherto poorly known or not described for the large-bodied trionychids of the Eocene of Europe can be performed for the first time. The study of the Belgian specimens, which correspond to the most complete and best preserved in Europe, allows us to evaluate the hypothesis on whether they belong to the same species as the other largebodied trionychids found in the Paleogene record of this continent. Thus, this study significantly increases the information on the relatively poorly known Paleogene large trionychids of Europe. This research was supported by network project BR/121/A3/PALEURAFRICA from the Belgian Science Policy Office, and by the Ministerio de Ciencia, Innovación y Universidades (IJCI-2016-30427).
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A DNA-based pipeline for species-level identification of Belgian mosquitoes
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RBINS Staff Publications 2021
