Search publications of the members of the Royal Belgian institute of natural Sciences
-
Morphological disparity of extant and extinct pinaceous ovulate cones: How many cones are enough?
- Abstract Premise The expansion of Pinaceae during the Cretaceous is exemplified by the numerous ovulate cone taxa found in western Europe and North America. The Belgian Wealden facies deposits have delivered hundreds of exceptionally well-preserved yet isolated pinaceous ovulate cones; these cones were placed by convention within form-genera. Ten species have been described in Belgium, representing about 20% of the known fossil record of this period. However, the validity of these taxa is questionable because their intra- and interspecific variabilities have never been thoroughly studied. Moreover, quantifying the expansion of Pinaceae in terms of morphospace occupation is desirable to reveal the dynamics of this critical radiation. Methods We used linear and geometric morphometry to quantify the shape of the extensive sample of Cretaceous cones of Belgium. These methods were also applied to extant pinaceous species to compare the morphological disparity of Cretaceous assemblages against those of today in selected ecosystems. We used ordination methods (PCA) to visualize morphospace occupation and test for species delineation. Results The morphological disparity was not higher in fossil species than in extant species we sampled. Both morphological approaches confirmed that the species Pityostrobus andraei presents high morphological variability. Our resampling tests indicate that ovulate cone morphological variability can be satisfactorily quantified with as few as 15 specimens. Conclusions The methodology used here is relevant for quantifying both the variability and the diversity of many fossil assemblages, paving the way for a more robust evaluation of Cretaceous pinaceous diversity.
-
Morphological disparity of extant and extinct pinaceous ovulate cones: How many cones are enough?
- Premise The expansion of Pinaceae during the Cretaceous is exemplified by the numerous ovulate cone taxa found in western Europe and North America. The Belgian Wealden facies deposits have delivered hundreds of exceptionally well-preserved yet isolated pinaceous ovulate cones; these cones were placed by convention within form-genera. Ten species have been described in Belgium, representing about 20% of the known fossil record of this period. However, the validity of these taxa is questionable because their intra- and interspecific variabilities have never been thoroughly studied. Moreover, quantifying the expansion of Pinaceae in terms of morphospace occupation is desirable to reveal the dynamics of this critical radiation. Methods We used linear and geometric morphometry to quantify the shape of the extensive sample of Cretaceous cones of Belgium. These methods were also applied to extant pinaceous species to compare the morphological disparity of Cretaceous assemblages against those of today in selected ecosystems. We used ordination methods (PCA) to visualize morphospace occupation and test for species delineation. Results The morphological disparity was not higher in fossil species than in extant species we sampled. Both morphological approaches confirmed that the species Pityostrobus andraei presents high morphological variability. Our resampling tests indicate that ovulate cone morphological variability can be satisfactorily quantified with as few as 15 specimens. Conclusions The methodology used here is relevant for quantifying both the variability and the diversity of many fossil assemblages, paving the way for a more robust evaluation of Cretaceous pinaceous diversity.
-
L’environnement de vie des premiers tétrapodes de Belgique
-
Flabellopteris lococannensis gen. et sp. nov.: A new fern-like plant from the Famennian of South Africa
- A new fossil plant, Flabellopteris lococannensis Gess and Prestianni gen. et sp. nov., is described from the Famennian of South Africa. This plant is interpreted as monopodial in habit with a first order axis that only occasionally dichotomizes. The lateral organs (both branches and appendages) are borne spirally on all branching orders and a 1/3 organotaxy is suggested. The first order axes bear both second order axes and fertile appendages at the same nodes. Axes of the second and third branching orders bear appendages made of several isotomous dichotomies. Recurved paired sporangia are borne on dichotomizing appendages that are like the vegetative appendages. The plant bears some similarity to the Iridopteridales but also to the Late Devonian Rhacophytales and to the Lower Carboniferous fernlike plant Chlidanophyton dublinensis. The architecture of the plant is briefly discussed and its implication on the evolution of the frond is considered.
-
The diversity of French Albian Pinaceae: a preliminary study of the Fliche (1896) material
- The Albian Gault Clay and Greensand Formation from the Argonne region (France) have yielded numerous plant remains including wood and an abundant (ca 100 specimens) collection of cones. Saporta (1880) and Fliche (1896) described some of these fossils that were attributed to seven species within Pinus. Two of these species have since been redescribed and renamed Pityostrobus oblongus Fliche 1896 and Pityostrobus argonnensis Fliche 1896 (Fliche 1896). The remaining five species, viz., Pinus praemontiloca Fliche 1896, P. wohlgemuthi Fliche 1896, P. praelepensis Fliche 1896, P. saportana Fliche 1896, and P. mammilifer Saporta 1880, still need to be restudied. We revised this material using X-ray micro-tomography and morphometry. We discuss the results of this work and try to clarify their taxonomy. In addition to the aforementioned published material, several specimens remained undescribed. Our preliminary results indicate, together with a new morphotype of pollen cone, the presence of at least two new morphotypes of ovulate cones. Some of the latter share many characters with Pinus, such as a very pronounced dorsal umbo. This high diversity matches that found in the Barremian–Aptian of Belgium and confirms the important diversity of Pinaceae in Western Europe during the Early Cretaceous.
-
The benthic foraminiferal response to the mid-Maastrichtian event in the NW-European chalk sea of the Maastrichtian type area
- The mid-Maastrichtian carbon isotope event (MME), dated at ∼69 Ma, reflects a perturbation of the global carbon cycle that, in part, correlates with the enigmatic global extinction of ‘true’ (i.e., non-tegulated) inoceramid bivalves. The mechanisms of this extinction event are still debated. While both the inoceramid extirpation and MME have been recorded in a variety of deep-sea sites, little is known about their expression in epicontinental chalk seas. In order to study the shallow-marine signature of the MME in this epicontinental shelf sea, we have generated quantitative foraminiferal assemblage data for two quarries (Hallembaye, NE Belgium; ENCI, SE Netherlands) in the Maastrichtian type area, complemented by a species-specific benthic δ13C record. In contrast to deep-sea records, no significant changes in benthic foraminiferal assemblages and benthic foraminiferal accumulation rates are observed across the MME in the type-Maastrichtian area. At the Hallembaye quarry, the otherwise rare endobenthic species Cuneus trigona reaches a transient peak abundance of 33.3% at the onset of the MME, likely caused by a local transient change in organic matter flux to the seafloor. Nevertheless, high and near-constant species evenness shows that neither oxygen nor organic matter flux was limited across the extinction level or during the MME. Benthic foraminiferal data from the uppermost part of the studied section, above the MME, indicate a significant increase in food supply to the seafloor. Decreased amounts of terrigenous elements across this interval document a lesser riverine or aeolian influx, which means that the increased benthic productivity is linked to a different origin. Potentially, the continuous precipitation of chalk under nutrient-poor conditions in the Late Cretaceous chalk sea was enabled by efficient nutrient recycling in the water column. In shallower depositional settings, nutrient recycling took place closer to the seafloor, which allowed more organic matter to reach the bottom. These results provide insights in the importance of nutrient cycling for biological productivity in the NW-European chalk sea.
-
Identification of Funding Priorities. Document OTSOPA 22/02/02 presented by Belgium and France at the Meeting of the Working Group on Operational, Technical and Scientific Questions Concerning Counter Pollution Activities (OTSOPA)
-
Discussion document on the status of the MAVI Working Groups on Strategic and Operational aspects (MAVI-SOWG) and Technical aspects (MAVI-TWG) and possible pathways towards a MAVI project proposal. Document OTSOPA 22/02/03 (+ Add. 1+2) presented by Belgiu
-
Minutes of the first meeting of the MAVI Technical Working Group (MAVI-TWG) held on 05/05/22. Document presented by the MAVI-TWG Co-convenors at the Meeting of the Working Group on Operational, Technical and Scientific Questions Concerning Counter Polluti
-
Significant Acute Pollution Events under the MSFD D8C3/D8C4. Document OTSOPA 22/02/05 Rev.1 (+ Add. 1) presented by Belgium and the Secretariat at the Meeting of the Working Group on Operational, Technical and Scientific Questions Concerning Counter Pollu
-
Draft report on Tour d’Horizon 2021 and multi-annual TdH trends. Document OTSOPA 22/05/02 presented by Belgium at the Meeting of the Working Group on Operational, Technical and Scientific Questions Concerning Counter Pollution Activities (OTSOPA)
-
Recent trends in MARPOL Annex II discharges in the Southern North Sea: FAME and POME. Document OTSOPA 22/05/06 presented by Belgium at the Meeting of the Working Group on Operational, Technical and Scientific Questions Concerning Counter Pollution Activit
-
Update from the ICG-IFP and text proposal on funding priorities for the BA website. Document BONN 22/3/2 presented by the Co-convenors of ICG-IFP at the 34th meeting of Bonn Agreement Contracting Parties
-
2021 Tour d’Horizon Report. Document BONN 22/3/4 presented by Belgium at the 34th meeting of Bonn Agreement Contracting Parties
-
Update on the status of the MAVI Working Groups on Strategic and Operational aspects (MAVI-SOWG) and Technical aspects (MAVI-TWG) and the OTSOPA22 outcome. Document BONN/3/5 (+ Add. 1+2) presented by the Co-convenors of SOWG & TWG at the 34th meeting of B
-
Significant acute pollution events under the MSFD D8C3/D8C4. Document BONN 22/3/6 (+ Add. 1+2) presented by Belgium and the Secretariat at the 34th meeting of Bonn Agreement Contracting Parties, Dublin, Ireland
-
Indices d’efficacité energétique.
-
Tour d’Horizon 2022, 05-09 September 2022. Mission Report
-
Airborne monitoring of compliance to sulfur emission regulations by ocean-going vessels in the Belgian North Sea area
-
Airborne monitoring of compliance to NOx emission regulations from ocean-going vessels in the Belgian North Sea
