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First crocodyliform fossils from the Eocene of Indonesia
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The Paleogene crocodyliform record is rich in taxonomic diversity, preserving crown and stemeusuchians alongside late-surviving neosuchians and notosuchians. This richness is mainly known from the extratropical latitudes of the New World and Eurasia, contrasting a poorly sampled tropical record. Within the tropics, the Paleogene of low-latitude southeast Asia is comparatively undersampled, with the Eocene Krabi Formation of Thailand representing the southernmost fauna. This crocodyliform fauna is composed of orientalosuchins and gavialoids, consistent with more northern records from southern Asia. Here we describe the first crocodyliform fossils from the Eocene of Indonesia, collected from the middle-late Eocene Talawi Member of the Sawahlunto Formation, west Sumatra. The Talawi Member represents a coastal swamp environment, preserving invertebrates, fish, and turtles along with rare frog, snake, and mammal fossils. Recovered crocodyliform fossils are often isolated and disarticulated, consisting of cranial remains including a partial braincase and jaw fragments, as well as relatively abundant teeth and osteoderms, vertebrae, and at least two autopodial elements. Procoelous vertebrae indicate eusuchian affinities. Osteoderms are diverse, with keeled and keelless squared and subrectangular forms. High and low-crowned fluted tooth morphotypes compare favorably to coeval gavialoids and orientalosuchins. A ziphodont form is present, potentially a planocraniid or sebecosuchian. External morphology of the braincase, such as narrow basioccipital tubera, a basioccipital plate bearing a crest, and a large basisphenoid exposure suggest a non-gavialoid identity. This is supported by preliminary observations of highresolution microCT scans, which imply a lateral carotid foramen ventral to the metotic foramen and laterally aligned medial and lateral eustachian foramina. The Sawahlunto fauna extends the southernmost geographical range of the Eocene southeast Asian crocodyliform fauna and represents the first multitaxon crocodyliform fauna from equatorial Asia. The ziphodont teeth either represent the last-occurring Asian planocraniids in a tropical refugium, or an incursion of Gondwanan sebecosuchians from India into the Asian tropics.
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RBINS Staff Publications 2025 OA
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First detailed study of the Belgian Eocene sea turtle ‘Oligochelone rupeliensis’
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In 1909, the famous palaeontologist Louis Dollo announced, in a paper about the Belgian fossil vertebrates, a new Oligocene (Rupelian) genus and species of sea turtle, ‘Oligochelone rupeliensis’. He indicated that it was established for a specimen that preserved the complete carapace and several appendicular bones, being characterized as “a typical marine turtle”. No further information, but neither photographs or drawings, were provided by him. He planned to publish the study of this species in the future, but this did not happen. Only a schematic drawing of the plastron of that specimen, as well as a photograph of a tibia attributed to this taxon without justification, were presented, by another author, seventy years later. The first-hand study of the specimen considered by Dollo allows us to observe that it does not preserve any tibia, so that attribution cannot be supported. Therefore, except for that imprecise drawing of the plastron published more than four decades ago, no additional information was available so far. In fact, ‘Oligochelone rupeliensis’ was recognized as a nomen nudum. After a preliminary analysis of the specimen considered by Dollo, one of us (APG) and other collaborators recently indicated, without justification, that, although ‘Oligochelone rupeliensis’ could be closely related to the Eochelone representatives, it differs from all defined members of Cheloniidae. Therefore, we point out that a detailed anatomical study of this form, as well as its comparison with other species, would be necessary to propose, for the first time, a diagnosis, if its specific validity can be confirmed. Taking this into account, that partial skeleton has been analyzed in detail by us. To improve the comparative framework, both the type material and additional individuals from all Eocene and Oligocene cheloniid taxa recognized for the Belgian record have also been analyzed first-hand. The preliminary results are presented here.
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RBINS Staff Publications 2025
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First multituberculate mammal from Russia
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RBINS Staff Publications
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First virtual endocasts of two Paleocene arctocyonids: a glimpse into the behavior of early placental mammals after the end-Cretaceous extinction
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Placentals are by far the most diverse group of mammals today, with 6,111 species. They occupy a plethora of ecological niches worldwide and display a broad range of body masses. The vacant niches left by non-avian dinosaurs and other vertebrates after the end-Cretaceous mass extinction provided a crucial opportunity for placentals to diversify; however, intrinsic factors also may have played a role. The general neurosensory organization exhibited by extant mammals has been maintained since the early Mesozoic. Much later, early members of extant placental groups from the Eocene and Oligocene including rodents, primates and artiodactyls—display neurosensory innovations such as a proportionally larger neocortex and higher encephalization quotient compared to their Mesozoic ancestors. However, between these two well-known intervals of mammalian neurosensory evolution, there is a gap: few studies have focused on the brains of the oldest placentals living during the early Paleogene, in the Paleocene. We focus on the ‘Arctocyonidae’, a likely polyphyletic group of ‘condylarths’, including species potentially implicated in the origins of some extant orders. ‘Arctocyonids’ were among the first placentals to diversify after the end-Cretaceous extinction. They have been reconstructed as small-tomedium sized, mainly omnivorous and terrestrial. We obtained cranial and bony labyrinth endocasts for Chriacus baldwini and C. pelvidens from the lower Paleocene of the San Juan Basin, New Mexico, and Arctocyon primaevus from the upper Paleocene of the Paris Basin, France, via high resolution computed tomography. Both share plesiomorphic brain features with previously described early Paleocene mammals. They have small lissencephalic brains with an EQ range of 0.12-0.43 and 0.16-0.31, respectively. The olfactory bulbs and the paraflocculi represent 6% and less than 1% of the total endocranial volume, respectively and the neocortical height ratio represents ~25% of the total endocranial height. Based on cochlear measurements, both taxa had hearing capabilities similar to those of extant wild boars. Agility scores between 2 and 3 were obtained for both taxa, similar to the modern American badger and crab-eating raccoon, suggesting that C. pelvidens and A. primaevus were ambulatory. These results support growing evidence that early placentals had lower EQs and less expanded neocortices compared to Eocene and later taxa, potentially indicating that high intelligence was not key to the placental radiation after the End-Cretaceous extinction. Grant Information: Marie Sklodowska-Curie Actions: Individual Fellowship, European Research Council Starting Grant, National Science Foundation, and Belgian Science Policy Office.
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RBINS Staff Publications 2019
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Five adjacent Aquifer Thermal Energy Storage (ATES) systems in Cenozoic and Paleozoic aquifers in Brussels: numerical simulation of their possible interactions
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RBINS Staff Publications 2023
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FORENSIC CLASSIFICATION OF METEORITES: THE CASE OF AN ORIENTED SPECIMEN FROM THE BELGIAN ANTARCTIC METEORITE COLLECTION
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Introduction: The meteorite classification processes require a sequence of semi-destructive to destructive analyses to elucidate the internal texture and chemical composition of the sample. Several methods have been proposed for classifying meteorites using a non-destructive approach such as magnetic susceptibility [1] or 3D petrographic analysis [2]. Specimens with unique orientation forms such as cone or shield-shaped, are often prioritized for non-destructive classification due to their significant exhibition value and insight into the aerodynamics of extraterrestrial material during their atmospheric entrance [3,4]. In this study, we present a description employing non-destructive analysis to classify a newly found flattened shield-shaped Antarctic meteorite discovered during the Belgian meteorite reconnaissance expedition 2022-2023 in the Sør Rondane area, East Antarctica [5]. This approach promises to provide detailed internal structural and information on physical properties without compromising the integrity of the sample. Methods: We utilized the X-ray Computed Tomography (XCT) RX Solutions EasyTom150 device at the Institute of Natural Sciences (Brussels, Belgique) to analyze the sample with dimensions of 37.1 mm x 44.0 mm x 52.6 mm (Fig. 1). A copper filter of 0.4 mm was used. The sample was scanned at a voxel size of 58.2 μm using the large focal spot mode at 145 kV, 38 W and 260 μA. We employed the program 3D Slicer [6] to analyze the three-dimensional properties and calculate the physical parameters. Additionally, magnetic susceptibility measurements were conducted on the field using an SM30 instrument. Preliminary results: Various forms of deformation, notably radial extension features, were detected, likely indicative of shock experiences undergone by the sample before entering the Earth’s atmosphere, hence corroborating its extraterrestrial origin (Fig. 1). Preliminary magnetic susceptibility measurement on the field indicated a value typical of L chondrites (log χ ~ 4.7 [5]). The interior XCT slices reveal that the sample comprises a dense metallic phase with few non-metallic inclusions, primarily located on the face opposite to the entry direction (red arrow in Fig. 1b). The total volume measures 22.09 cm3, with a corresponding mass of 151.1 g, indicating a meteorite bulk density of 6.8 g cm-3 comparable to iron meteorites (bulk density between 7 and 8 g cm-3 [7]). This is at odds with the preliminary magnetic susceptibility measurement. Additional non-destructive analyzes will be needed, notably μ-XRF measurements to offer a better comprehension of the origin of the sample. This underlines the difficulty of classifying a sample in a non-destructive manner
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RBINS Staff Publications 2024
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From brown to blue water: Unraveling spatio-temporal variations in the organic matter content of suspended particulate matter
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RBINS Staff Publications 2023
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From toad to frog: osteological description and taxonomic reattribution of the 'mummified' holotype of Bufo servatus, an Eocene anuran, based on micro-CT examination
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The Quercy Phosphorites are a set of Eocene-Oligocene deposits from South-West France that yielded numerous vertebrate fossils, including amphibians, mostly as isolated bones. However, in 1873, several exceptional amphibian specimens were discovered, with the external surface of the unmineralized tissues preserved, and were commonly referred as “mummies”. In the 19th century, they were described without any knowledge of their internal anatomy. Since 2012, we have started scanning these “mummies”, revealing the preserved internal soft tissues and articulated skeleton. A first specimen was attributed in 2013 to Thaumastosaurus gezei and we here present our results from the tomography of a second “mummified” anuran, previously identified as Bufo servatus. The tomography showed a preserved articulated skeleton, and its osteological characteristics are similar to the first scanned anuran “mummy”, representing different ontogenetic stages. Both are now both attributed to Thaumastosaurus servatus nov. comb. The new anatomical information is used to assess the affinities of T. servatus, which appears to belong to the Pyxicephalidae, an African anuran clade. Thaumastosaurus thus represents both the oldest occurrence of this clade in the fossil record and its first occurrence outside of Africa. Its presence in Europe highlights a faunistic exchange with Africa during the Eocene, also documented for several clade of squamates. The presence of this African herpetofauna in Europe might be linked to the warmer climate during the Eocene. However, most of this herpetofauna, including Thaumastosaurus, disappeared from the region around an extinction event (named the “Grande Coupure”) that took place around the Eocene/Oligocene transition (~34 Ma).
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RBINS Staff Publications 2021
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Geo-techno-economic assessment of CO2 capture, transport, and storage chain options for a cement plant in Germany
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RBINS Staff Publications 2024
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Geophysical well log correlations in the Quaternary deposits of the Campine area, northern Belgium
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RBINS Staff Publications 2021
