Search publications of the members of the Royal Belgian institute of natural Sciences
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Endocranial anatomy and phylogenetic position of the crocodylian Eosuchus lerichei from the late Paleocene of northwestern Europe and potential adaptations for transoceanic dispersal in gavialoids
- Eosuchus lerichei is a gavialoid crocodylian from late Paleocene marine deposits of northwestern Europe, known from a skull and lower jaws, as well as postcrania. Its sister taxon relationship with the approximately contemporaneous species Eosuchus minor from the east coast of the USA has been explained through transoceanic dispersal, indicating a capability for salt excretion that is absent in extant gavialoids. However, there is currently no anatomical evidence to support marine adaptation in extinct gavialoids. Furthermore, the placement of Eosuchus within Gavialoidea is labile, with some analyses supporting affinities with the Late Cretaceous to early Paleogene “thoracosaurs.” Here we present novel data on the internal and external anatomy of the skull of E. lerichei that enables a revised diagnosis, with 6 autapormorphies identified for the genus and 10 features that enable differentiation of the species from Eosuchus minor. Our phylogenetic analyses recover Eosuchus as an early diverging gavialid gavialoid that is not part of the “thoracosaur” group. In addition to thickened semi-circular canal walls of the endosseous labyrinth and paratympanic sinus reduction, we identify potential osteological correlates for salt glands in the internal surface of the prefrontal and lacrimal bones of E. lerichei. These salt glands potentially provide anatomical evidence for the capability of transoceanic dispersal within Eosuchus, and we also identify them in the Late Cretaceous “thoracosaur” Portugalosuchus. Given that the earliest diverging and stratigraphically oldest gavialoids either have evidence for a nasal salt gland and/or have been recovered from marine deposits, this suggests the capacity for salt excretion might be ancestral for Gavialoidea. Mapping osteological and geological evidence for marine adaptation onto a phylogeny indicates that there was probably more than one independent loss/reduction in the capacity for salt excretion in gavialoids.
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The cranium and dentition of Khirtharia (Artiodactyla, Raoellidae): new data on a stem taxon to Cetacea
- Raoellid mammals are small artiodactyls from the Eocene of Asia, hypothesized to be closely related to stem Cetacea. Knowledge of the cranial and dental morphology of Raoellidae comes mostly from one species, Indohyus indirae. Here we describe new material of another raoellid genus, Khirtharia, based on material retrieved from the Kalakot area, Jammu and Kashmir. This new material, comprising an almost complete, lightly deformed cranium and a partial snout with associated partial mandible, greatly adds to our knowledge of raoellid morphology. It highlights the similarity of cranial characters with Indohyus, such as a long snout with raptorial incisors, a thick and narrow supraorbital region, a strong postorbital constriction, a triangular shaped braincase, and a thickened medial wall to the auditory bulla (involucrum). The new specimen is similar to Indohyus cranially but differs dentally in being more bunodont. The presence of these traits in two different raoellid genera suggests they may be present more broadly across Raoellidae. These characters are also observed in early cetaceans, highlighting the need to investigate their phylogenetic impact. Some cranial features support aquatic habits of members of this family.
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First fossil record of Mustelus aff. punctulatus Risso, 1826: new evidence for a smooth-hound shark population in the Late Miocene North Sea Basin
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The bats of the Congo and of Rwanda and Burundi Revisited (Mammalia: Chiroptera)
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The complete phylogeny of extant pangolins: scaling up the molecular tracing of the most trafficked mammals on earth
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Genetic turnovers and northern survival during the last glacial maximum in European brown bears
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Consequences of past climate change and recent human persecution on mitogenomic diversity in the arctic fox
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Ancient DNA suggests modern wolves trace their origin to a Late Pleistocene expansion from Beringia
- Abstract Grey wolves (Canis lupus) are one of the few large terrestrial carnivores that have maintained a wide geographical distribution across the Northern Hemisphere throughout the Pleistocene and Holocene. Recent genetic studies have suggested that, despite this continuous presence, major demographic changes occurred in wolf populations between the Late Pleistocene and early Holocene, and that extant wolves trace their ancestry to a single Late Pleistocene population. Both the geographical origin of this ancestral population and how it became widespread remain unknown. Here, we used a spatially and temporally explicit modelling framework to analyse a data set of 90 modern and 45 ancient mitochondrial wolf genomes from across the Northern Hemisphere, spanning the last 50,000 years. Our results suggest that contemporary wolf populations trace their ancestry to an expansion from Beringia at the end of the Last Glacial Maximum, and that this process was most likely driven by Late Pleistocene ecological fluctuations that occurred across the Northern Hemisphere. This study provides direct ancient genetic evidence that long-range migration has played an important role in the population history of a large carnivore, and provides insight into how wolves survived the wave of megafaunal extinctions at the end of the last glaciation. Moreover, because Late Pleistocene grey wolves were the likely source from which all modern dogs trace their origins, the demographic history described in this study has fundamental implications for understanding the geographical origin of the dog.
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Ancient DNA suggests modern wolves trace their origin to a Late Pleistocene expansion from Beringia
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Editorial: Antarctic Biology: Scale Matters
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Editorial: Antarctic Biology: Scale Matters
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Penaeus aztecus Ives, 1891 (Crustacea, Decapoda), in the Scheldt estuary (Belgium): Isolated record or forerunner of a penaeid invasion?
- A single specimen of the penaeid prawn Penaeus aztecus (Ives, 1891) was recorded in 2018 in the brackish zone of the Scheldt estuary near Antwerp (Belgium). The presence of this species, native to the West Atlantic, might result either from ships' ballast water coming from transatlantic boat shipping, from illegal import or from a considerable expansion leap northwards from the Mediterranean Sea, where this species has recently established and now has rapidly expanding invasive populations.
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Changes in chlorophyll concentration and phenology in the North Sea in relation to de-eutrophication and sea surface warming
- At least two major drivers of phytoplankton production have changed in recent decades in the North Sea: sea surface temperature (SST) has increased by ~ 1.6C between 1988 and 2014, and the nitrogen and phosphorus loads from surrounding rivers have decreased from the mid-1980s onward, following reduction policies. Long time series spanning four decades (1975–2015) of nutrients, chlorophyll (Chl), and pH measurements in the Southern and Central North Sea were analyzed to assess the impact of both the warming and the deeutrophication trends on Chl. The de-eutrophication process, detectable in the reduction of nutrient river loads to the sea, caused a decrease of nutrient concentrations in coastal waters under riverine influence. A decline in annual mean Chl was observed at 11 out of 18 sampling sites (coastal and offshore) in the period 1988–2016. Also, a shift in Chl phenology was observed around 2000, with spring bloom formation occurring earlier in the year. A long time series of pH in the Southern North Sea showed an increase until the mid-1980s followed by a rapid decrease, suggesting changes in phytoplankton production that would support the observed changes in Chl. Linear correlations, however, did not reveal significant relationships between Chl variability and winter nutrients or SST at the sampling sites. We propose that the observed changes in Chl (annual or seasonal) around 2000 are a response of phytoplankton dynamics to multiple stressors, directly or indirectly influenced by deeutrophication and climate warming.
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New early Eocene vertebrate assemblage from western India reveals a mixed fauna of European and Gondwana affinities
- Abstract The Ypresian Cambay Shale Formation at Vastan and Mangrol lignite mines in Gujarat, western India, has yielded a rich vertebrate fauna with numerous taxa of European affinities. Here we report a new, approximately contemporary vertebrate assemblage from two fossiliferous layers in the nearby mine of Tadkeshwar. These layers have yielded a similar mammal fauna with the co-occurrence of the perissodactyl-like cambaytheriid Cambaytherium thewissi, the adapoid primates Marcgodinotius indicus and cf. Asiadapis cambayensis, and the hyaenodontid Indohyaenodon raoi. The presence of these species in both Vastan and Tadkeshwar mines and at different levels suggests that the deposits between the two major lignite seams represent a single land mammal age. Apart from the aforementioned species there is a new, smaller species of Cambaytherium, and a new genus and species of esthonychid tillodont. This fauna also contains the first large early Eocene vertebrates from India, including an unidentified Coryphodon-like pantodont, a dyrosaurid crocodyliform and a new giant madtsoiid snake. Among the Tadkeshwar vertebrates several taxa are of Gondwana affinities, such as Pelomedusoides turtles, dyrosaurids, and large madtsoiids, attesting that the early Eocene was a crucial period in India during which Laurasian taxa of European affinities co-existed with relict taxa from Gondwana before the India-Asia collision. Our results suggest that terrestrial faunas could have dispersed to or from Europe during episodes of contact between the Indian subcontinent and different island blocks along the northern margin of the Neotethys, such as the Kohistan–Ladakh island-arc system. Gondwana taxa might represent remnants of ghost lineages shared with Madagascar, which reached the Indian subcontinent during the late Cretaceous; alternatively they might have come from North Africa and passed along the southern margin of the Neotethys to reach the Indian subcontinent. These dispersals would have been possible as a result of favourable paleogeographic conditions such as the particular Neotethys conformation during the beginning of the early Eocene.
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Histology and growth of Iguanodon bernissartensis
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Environmental impact assessment in line with the EU Nature Directives
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Dinosaur ecology and climate in Eastern Siberia during the Late Cretaceous inferred from stable isotopes
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Changes in bottom shear stress, due to aggregate extraction in the area of the Hinder Banks (Belgian Continental Shelf)
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WP4 – Sediment plume dilution and disperion, Activity Report 1 January 2015 – 31 December 2015
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Synthesis report on the effects of dredged material disposal on the marine environment (licensing period 2012-2016)
