Search publications of the members of the Royal Belgian institute of natural Sciences
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Biodiversity of Belgian groundwater fauna in relation to environmental conditions
- 1. The Pleistocene glaciations during the Quaternary appear to have resulted in an impoverished groundwater fauna in northern Europe. Re-colonisation may have occurred either through long-distance dispersal from unglaciated southern areas or from local refugia. 2. The Belgian groundwater fauna was sampled at multiple sites, and its habitats characterised, to assess whether the composition of present-day stygobiotic assemblages can be attributed to either of these mechanisms. 3. A total of 202 sampling sites were selected in four hydrogeographic units of the Meuse River catchment. Sites were equally divided among the saturated and unsaturated zones of fractured aquifers (karst) and within the hyporheic and phreatic zones of porous aquifers. Seventeen environmental parameters were determined in parallel. 4. More than 140 species were recorded, including representatives of the Amphipoda, Cladocera, Copepoda, Hydrachnidia, Isopoda, Oligochaeta, Ostracoda, Mollusca, Syncarida and Nematoda. Thirty stygobiont specieswere identified, of which10 species were new to the Belgian fauna, raising the total number of stygobiotic species in Belgium to 41. 5. The frequency of occurrences of stygobiotic species was always low, with 37% of the sampled sites lacking stygobionts. A few species were exclusive to one hydrological zone, although no statistically significant differences were detected in species richness at any of the four hierarchial levels considered (Meuse catchment = region, hydrogeographic units, aquifer type and hydrological zone). 6. Overall, results suggest that the stygobiotic fauna of Belgium is species-poor and mostly comprises widely distributed species with broad ecological tolerances. This supports the view that eurytopic species re-colonised the area by long-distance dispersal from refugia in southern Europe. The virtual absence of endemic species further suggests that the scenario of an ancient fauna that survived in local refugia is of minor importance.
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Additional postcranial elements of Teilhardina belgica: the oldest European Primate
- Teilhardina belgica is one of the earliest fossil primates ever recovered and the oldest fossil primate from Europe. As such, this taxon has often been hypothesized as a basal tarsiiform on the basis of its primitive dental formula with four premolars and a simplified molar cusp pattern. Until recently [see Rose et al.: Am J Phys Anthropol 146 (2011) 281–305; Gebo et al.: J Hum Evol 63 (2012) 205–218], little was known concerning its postcranial anatomy with the exception of its well-known tarsals. In this article, we describe additional postcranial elements for T. belgica and compare these with other tarsiiforms and with primitive adapiforms. The forelimb of T. belgica indicates an arboreal primate with prominent forearm musculature, good elbow rotational mobility, and a horizontal, rather than a vertical body posture. The lateral hand positions imply grasps adaptive for relatively large diameter supports given its small body size. The hand is long with very long fingers, especially the middle phalanges. The hindlimb indicates foot inversion capabilities, frequent leaping, arboreal quadrupedalism, climbing, and grasping. The long and well-muscled hallux can be coupled with long lateral phalanges to reconstruct a foot with long grasping digits. Our phyletic analysis indicates that we can identify several postcranial characteristics shared in common for stem primates as well as note several derived postcranial characters for Tarsiiformes.
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Early Eocene fossils suggest that the mammalian order Perissodactyla originated in India
- Cambaytheres (Cambaytherium, Nakusia and Kalitherium) are recently discovered early Eocene placental mammals from the Indo–Pakistan region. They have been assigned to either Perissodactyla (the clade including horses, tapirs and rhinos, which is a member of the superorder Laurasiatheria) or Anthracobunidae, an obscure family that has been variously considered artiodactyls or perissodactyls, but most recently placed at the base of Proboscidea or of Tethytheria (ProboscideaþSirenia, superorder Afrotheria). Here we report new dental, cranial and postcranial fossils of Cambaytherium, from the Cambay Shale Formation, Gujarat, India (B54.5 Myr). These fossils demonstrate that cambaytheres occupy a pivotal position as the sister taxon of Perissodactyla, thereby providing insight on the phylogenetic and biogeographic origin of Perissodactyla. The presence of the sister group of perissodactyls in western India near or before the time of collision suggests that Perissodactyla may have originated on the Indian Plate during its final drift toward Asia.
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Late Palaeocene eusuchian remains from Mont de Berru, France, and the origin of the alligatoroid Diplocynodon
- Crocodilian remains from the late Palaeocene continental locality of Mont de Berru (Marne, France) offer the opportunity to reassess the taxonomic identity of the oldest diplocynodontid from Europe. Owing to significant morphological differences from previously described species of Diplocynodon, which include the presence of a splenial symphysis, a new species, Diplocynodon remensis sp. nov., is erected here. Its inclusion in a phylogenetic framework for Eusuchia leads to its positioning as a derived member of diplocynodontids. Diplocynodontidae are viewed as a basal alligatoroid taxon, and, because morphological affinities with the Late Cretaceous−early Eocene North American genus Borealosuchus were mentioned in earlier studies, a comparison amongst D. remensis sp. nov., Leidyosuchus, and Borealosuchus spp. is presented. Although D. remensis sp. nov. is the geologically oldest diplocynodontid, according to our results, it is not the phylogenetically most primitive. Other morphological discrepancies are highlighted, indicating that the topology recovered here is only tentative. From a biogeographical point of view, the appearance of Diplocynodon in Europe prior to the Palaeocene/Eocene boundary indicates that it did not disperse with North American taxa that reached Europe around the time of the Palaeocene-Eocene thermal maximum (PETM). Therefore, a pre-PETM dispersal from North America at the same times as other vertebrates with clear North American affinities also occurring in the Palaeocene of Europe cannot be excluded. The description of D. remensis sp. nov. adds substantial new, albeit conflicting, information, highlighting the need for a better phylogenetic framework with a revision of other critical taxa (Menatalligator, Borealosuchus) from the Palaeocene of Europe and North America.
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A new kogaionid multituberculate mammal from the Maastrichtian of the Transylvanian Basin, Romania
- Abstract: The Latest Cretaceous (Maastrichtian) terrestrial sedimentary sequences of the Hateg Basin in Transylvania are well known for the so-called “Hateg Island” vertebrate faunas, which evolved in endemic (insular?) conditions. In addition to frogs, lizards, turtles, crocodilians, birds and dinosaurs, peculiar multituberculate mammals have been recorded, all belonging to the family Kogaionidae. Here, a new species of the genus Barbatodon is reported from the Maastrichtian S¸ ard Formation in the Transylvanian Basin (Alba County, Romania). Barbatodon oardaensis n. sp. is characterized by M1 cusp formula 3:4:2 and is much smaller than the two other Maastrichtian kogaionids from Transylvania, Barbatodon transylvanicus and Kogaionon ungureanui. The origin and paleobiogeography of kogaionids are discussed. Résumé: Les séquences continentales du Crétacé terminal (Maastrichtien) du bassin de Hateg en Transylvanie sont réputées pour leurs faunes de vertébrés originaires de « l’île de Hateg », qui ont évolué dans des conditions endémiques (insulaires ?). Hormis des grenouilles, lézards, tortues, crocodiles, oiseaux et dinosaures, des mammifères multituberculés particuliers ont également été mentionnés, tous appartenant à la famille des Kogaionidae. Une nouvelle espèce du genre Barbatodon est décrite dans le Maastrichtien de la Formation de S¸ ard, dans le bassin de Transylvanie (district d’Alba, Roumanie). Barbatodon oardaensis n. sp. est caractérisée par une formule dentaire de M1 3:4:2 et est plus petite que les deux autres kogaionidés de Transylvanie, Barbatodon transylvanicus et Kogaionon ungureanui. L’origine et la paléobiogéographie des kogaionidés sont discutées.
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Paleobiogeography of the lotus plant (Nelumbonaceae: Nelumbo) and its bearing on the paleoclimatic changes
- The historical reconstruction of the origin and dispersal of plant taxa in space and time facilitates a better understanding of theirmodern distribution patterns. However,most studies of paleobiogeography have focused on terrestrial plants, and the distribution changes of aquatic plants are less well understood. Here we study the lotus plant Nelumbo (Nelumbonaceae), an aquatic perennial herb, with a disjunctive distribution across East, South and Southeast Asia-North Australia and North America. The reproductive organs of Nelumbo changchangensis He et Jin from the Eocene of Hainan, China are supplementarily described. Analysis of the spatial and temporal distributions of Nelumbo in the geologic past indicates that the genus first occurs in mid-latitude area of Laurasia in the Early Cretaceous, then becomeswidespread in North America and Eurasia and expands into SouthAmerica during the Late Cretaceous, and reaches its maximum northern limit during the Eocene. The genus persists and thrives in North America and Eurasia until the Pliocene. The Pleistocene ice age causes the extinction of Nelumbo in Europe and central Asia, and its populations in North American and Asia are also restricted to refuges of lower latitude. Like the terrestrial plants Metasequoia (Cupressaceae) and Nordenskioeldia (Trochodendraceae), the fluctuations of Nelumbo distribution ranges are also linked to climatic changes in the Cenozoic. The cooling climate and increasing seasonality in the Eocene of East Asia may favor the origin of tubers and the differentiating of the ecotypes in lotus, which allow the deciduous type to survive in cold winters.
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A ziphodont crocodylomorph from the Eraly Eocene of Vastan Lignite Mine (Gujarat, India)
- Since 2004, the early Eocene Vastan lignite mine (Cambay Shale Formation, Gujarat, Western India) has yielded a rich herpetofauna with frogs, snakes, and lizards (Rage et al., 2008; Folie et al., 2013; Rana et al., 2013). But it is only in January 2012 that the first crocodylomorph remains were retrieved all together in one very thin lens of a few meters width. This small collection includes 4 teeth, 3 fragmentary vertebrae, 1 fragmentary femur, and 2 metapodials. All the teeth are characterized by being distinctly elongated and labiolingually compressed. When well preserved, the mesiodistal carinae bear distinct serrations of the enamel (the ziphodont condition). The largest crown available is estimated to be at least 30 mm tall. In labial or lingual view, the outline of the crown is rather symmetrical. On the other hand, the smallest tooth is asymmetrical being curved in labial view with a nearly straight distal margin and a convex mesial margin. The fragmentary vertebrae share a slightly amphicoelous condition of the centrum. The largest centrum is 32.9 mm long and the neurocentral suture not clearly visible. A modest but well visible hypapophysis is placed close to the anterior edge of the centrum of both these vertebrae. The fragmentary left femur is represented by a proximal portion 45.0 mm long, extending from the totally eroded epiphysis to slightly distally to the fourth trochanter. The largest diameter at the level of the trochanter is 11.6 mm. The ziphodont crocodylomorph teeth reported from a few Paleogene localities of the Indian subcontinent have been referred to both Pristichampsinae and Sebecosuchidae (Sahni & Srivastava, 1976; Buffettaut, 1978; Sahni et al., 1978; Gupta & Kumar, 2013). However, the latter taxon is considered absent in the Tertiary of Asia and amphyplatian vertebrae found in association with ziphodont teeth have been referred to dyrosaurids (Buffettaut, 1978; Turner & Calvo, 2005). Although non-eusuchian crocodylomorphs are restricted to two groups in the Paleogene (Dyrosauridae and Sebecosuchia), our limited knowledge of their postcranial anatomy renders identification of fragmentary remains difficult. Different hypotheses for the identity of the crocodylomorph remains from Vastan are presented.
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The oldest blind snake is in the Early Paleocene of Europe
- Scolecophidians or blind snakes are among the most primitive and smaller snakes in the world with an average of size of 10 cm. They are worm-like, fossorial, lucifugous and often colourless, eating ants, termites, and their larvae. Based on the revision of Vidal et al (2010) they are represented by 5 families mainly living in tropical areas and have had a long history on Gondwana. The only European representative of this group is Typhlops vermicularis that lives around the Mediterranean Basin. Here we describe two isolated procoelous trunk vertebrae from the early Paleocene of Hainin (MP1-5, Belgium), a locality already known for the oldest amphisbaenian lizards (Folie et al 2013) and the earliest European scincoid lizards (Folie et al 2005). These vertebrae are clearly attributed to a scolecophian by the following characters (List, 1966): they are 1.5 mm long and 1 mm high and wide; the centrum is narrow and the hemal keel is absent; the orientation of the prezygapophyses processes that serve for muscle attachment strongly differs from the one of the prezygapophyseal facets; the neural arch is depressed and does not present a posterior medial notch nor a neural spine. Fossil scolecophidians are identified based on their vertebrae but they are generally considered as not diagnostic at a familial, generic or specific level. However, some characters have recently been proposed to differentiate the family level on the basis of the shape and placement of the synapophyses, shape of the cotyle, size of the zygosphene, and shape of the prezygopophyseal facets (Gelnaw & Mead, 2010). Based on these features, the Hainin vertebrae differ from those of Anomalepidae and Leptotyphlopidae, and resemble those of Typhlopidae by similar neural arch morphology and height, development and orientation of the paradiapophysis, and morphology of the neural canal, cotyle and condyle. Record of fossil scolecophidians indicates their presence in North America, Europe, Africa and Australia. Before this study, the oldest representatives of this group were known from the late Paleocene of Adrar Mgorn (Ouarzazate Basin) in Morrocco and from the earliest Eocene of Dormaal (Tienen Formation, MP7) in Belgium. The scolecophidian from Hainin resembles more the one from Dormaal than that from Adrar Mgorn by narrower centrum and neural arch. The width of the neural arch in Typhlops is similar to both Belgian scolecophidians, however, the centrum is even narrower. By these characters, the scolecophidian from Hainin could represent a basal Typhlopidae.
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Reconstruction of the skeleton of Teilhardina belgica, the oldest European Primate
- Teilhardina belgica is one of the earliest fossil primates ever recovered and the oldest fossil primate from Europe (~ 56 Million years). It was originally described by Teilhard de Chardin (1927) from the MP7 reference level of Dormaal (Belgium), which is situated at the Paleocene-Eocene boundary at the base of the Tienen Formation (Smith & Smith, 1996). Teilhardina is known on all three northern continents in association with the carbon isotope excursion marking the Paleocene–Eocene Thermal Maximum. Relative position within the carbon isotope excursion indicates that Asian Teilhardina asiatica is oldest, European T. belgica is younger, and North American T. brandti and T. americana are, successively, youngest. Analysis of morphological dental characteristics of all four species supports an Asian origin and a westward Asia-to-Europe-to-North America dispersal for Teilhardina. High-resolution isotope stratigraphy indicates that this dispersal happened in an interval of 25,000 years (Smith et al, 2006). Moreover, Teilhardina is one of the most primitive fossil primates known to date and the earliest haplorhine with associated three dimensional postcranials making it relevant to a reconstruction of the ancestral primate morphotype. As such, Teilhardina has often been hypothesized as a basal tarsiiform on the basis of its primitive dental formula with four premolars and a simplified molar cusp pattern. Until recently, little was known concerning its postcranial anatomy with the exception of its well-known tarsals. Here we describe additional postcranial elements for Teilhardina belgica and compare these to other tarsiiforms and to primitive adapiforms. Teilhardina is a small primate with an estimated body mass between 30-60 g, similar to the size of a mouse lemur. Its hindlimb anatomy suggests frequent and forceful leaping with excellent foot mobility and grasping capabilities. It can now be established that it exhibits critical primate postcranial synapomorphies such as a grasping hallux and a tall knee (Gebo et al, 2012), and nailed digits (Rose et al, 2011). This anatomical pattern and behavioral profile is similar to what has been inferred before for other omomyids and adapiforms. The most unusual feature of Teilhardina belgica is its elongated middle phalanges suggesting that this early primate had very long fingers similar to those of living tarsiers. Our phyletic analysis indicates that we can identify several postcranial characteristics shared in common for stem primates as well as note several derived postcranial characters for Tarsiiformes.
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Early Eocene cambaytheres from Indo-Pakistan are the sister group of Perissodactyls
- Cambaytherium, Nakusia, and Kalitherium are closely related early Eocene mammals from the Indo-Pakistan region that have been assigned to Perissodactyla (Laurasiatheria)or Anthracobunidae. The latter have been variously considered artiodactyls or perissodactyls, but more recently are usually placed at the base of the order Proboscidea or of the more inclusive Tethytheria (Afrotheria). We present new evidence from the dentition, skull, and postcranial skeleton of Cambaytherium, from Gujarat, India (ca. 54.5 Ma), that cambaytheres occupy a pivotal position as the sister taxon of Perissodactyla. Cambaytherium was more robust than basal perissodactyls such as ″Hyracotherium″ and Homogalax, and had a body mass of ~25-27 kg based on humeral, radial, and dental regressions. Perissodactyl synapomorphies include a transverse nasal-frontal suture, twinned molar metaconids, and an astragalus with deeply grooved trochlea and a saddleshaped navicular facet. Like perissodactyls, cambaytheres are mesaxonic and have hooflike unguals and a cursorially-adapted skeleton. Plesiomorphic traits compared to basal perissodactyls include bunodont molars with large conules and almost no hint of bilophodonty, unmolarized premolars, sacrum with four vertebrae, humerus with distally extensive pectoral crest and distal articulation lacking a capitular tail, distal radius without discrete scaphoid and lunate fossae, femur with low greater trochanter, calcaneus robust and wide with rounded ectal facet, astragalus wide with moderately long neck and vestigial astragalar foramen, navicular and cuboid short and wide, metapodials short and robust, and Mc I and Mt V present. In most or all of these traits cambaytheres are intermediate between phenacodontid condylarths and perissodactyls but closer to the latter. Our phylogenetic analyses place cambaytheres just outside perissodactyls, and place anthracobunids among primitive perissodactyls. However, similarities between cambaytheres and anthracobunids suggest that they are closely related, and future discovery of skeletal material of anthracobunids will provide a test of this hypothesis. Our results indicate that Anthracobunidae are not Proboscidea or tethytheres, and suggest that the origin of Perissodactyla may have taken place on the drifting Indian plate. How the progenitors of perissodactyls reached India is more problematic but might have involved land connections with Afro-Arabia during the Paleocene. Field work and research supported by the National Geographic Society.
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Focus stacking: Comparing commercial top-end set-ups with a semi-automatic low budget approach. A possible solution for mass digitization of type specimens
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Elementen van de populatiedynamiek van de Oehoe (Bubo bubo) in de Ardennen.
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Eocene stratigraphy of the Wadi Al-Hitan World Heritage Site and adjacent areas (Fayum, Egypt).
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Habitat selection by Red-breasted Geese (Branta ruficollis) wintering in Eastern Europe
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Early Eocene environmental development in the northern Peri-Tethys (Aktulagay, Kazakhstan) based on benthic foraminiferal assemblages and stable isotopes (O, C).
- The Aktulagay section in Kazakhstan provides an expanded northern Tethyan record of the middle Ypresian (calcareous nannoplankton zones NP11-13, ~ 54-50 Ma), including the Early Eocene Climatic Optimum (EECO). The marl sequence features a series of sapropel beds, observed throughout the Peri-Tethys, indicative of the basin-wide occurrence of episodic hypoxic events. In order to unravel the paleoenvironmental evolution at Aktulagay during this period of global warming, we investigated the benthic foraminiferal record by means of a detailed multivariate analysis of the > 63 μm fraction, as well as through stable isotopic (C, O) investigations on excellently preserved benthic foraminiferal specimens. The Alashen Formation (NP11 to lower NP12; ~ 54 to 52.5 Ma), in the lower part of the sequence, contains a diverse assemblage of deep outer neritic (~ 200-250 m) benthic foraminifera, with common Pulsiphonina prima and Paralabamina lunata. The sea-floor conditions are interpreted as initially (54 Ma) well-ventilated and oligo- to mesotrophic, gradually changing to more eutrophic and oxygen-limited, culminating in more permanent low-oxygen conditions and eutrophy in the sapropel-bearing Aktulagay B1 unit (middle NP12; ~ 52.5-52 Ma). The latter conclusion is corroborated by the dominance of Anomalinoides acutus and Bulimina aksuatica and the lower diversity. Also the upward migration of endobenthic species to the sediment-water interface, as suggested by rising δ13Cendobenthic values, supports this interpretation. A transgression, which flooded lowlands, might have caused this development. In the Aktulagay B2 unit (top NP12-NP13; ~ 52-50 Ma), benthic foraminiferal assemblages dominated by Epistominella minuta suggest an oligotrophic environment, with transient pulses of phytodetritus and moderate ventilation. The Aktulagay B2 unit coincides with the peak temperature interval of the EECO, as indicated by its position close to the base of NP13 and rising δ13Cepibenthic values. Large river plumes, episodically reaching the area, in a monsoonal climatic context, might explain this basin development. Although it is not unlikely that some of the observed patterns are related to long-term climate change, it can currently not be excluded that changing paleogeography and variable connections to the Tethys, Atlantic and the Arctic Ocean were responsible for the long-term period with dysoxia and anoxia during deposition of the sapropel beds at the Peri-Tethyan seafloor. The evolution of the basin as observed in Aktulagay shows similarities to the evolution of the North Sea Basin as observed in Denmark, suggesting that these basins were connected during the Early Eocene.
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Satellite tracking of the highly endangered Slender-billed Curlew : why and how ?
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An international conservation project for the Slender-billed Curlew (Numenius tenuirostris) in Greece: the first results.
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A new approach to locating Slender-billed Curlew breeding grounds.
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Overview of the life history of the Slender-billed Curlew.
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In search of the breeding grounds of the Slender-billed Curlew.
