Netherlands Journal of Geosciences

Bryozoan assemblages of the Gulpen Formation (upper Campanian – upper Maastrichtian) in the Liège-Limburg area (Belgium, the Netherlands)

Oliver Kesselhut, Luc Goffings, Johan Vellekoop — Mon, 03 Jun 2024 00:00:00 -0700

Renewed interest in bryozoan assemblages from the various members of the Gulpen Formation (upper Campanian–upper Maastrichtian) in the Liège-Limburg area (southeast Netherlands and northeast Belgium) during recent years has resulted in the discovery of a number of species previously unrecorded from the area. Nineteen species are here recorded from the Zeven Wegen, Vijlen, Lixhe and Lanaye members (Gulpen Formation) in the study area, occurring in three distinct assemblages. The vast majority of the bryozoan taxa belong to the order Cheilostomata; only two taxa are assigned to the order Cyclostomata. The species recorded here are Clinopora aff. costulata, Disporella obvallata, ‘Vincularia’ (sensu lato) marssoniana, Herpetopora laxata, Heteroconopeum ovatum, Wilbertopora aff. oxyteichos, Biaviculigera sacerdotalis, Semiflustrella britannica, Aechmellina anglica, Escharifora papyracea, Onychocella cyclostoma, Onychocella cylindrica, Onychocella matrona, Rhebasia disparilis, Stichomicropora sicksi, Coscinopleura elegans, Coscinopleura lamourouxi, Pachydermopora pachyderma and Beisselina aviculifera. While not previously recorded from the Liège-Limburg area, the bryozoan taxa identified from the Gulpen Formation are well known from coeval Cretaceous strata elsewhere in Europe, North America and Russia, highlighting their broad palaeobiogeographical distribution.

Remarkable insights into modern bird origins from the Maastrichtian type area (north-east Belgium, south-east Netherlands)

Mon, 13 May 2024 00:00:00 -0700

For centuries, fossils from the Maastrichtian type locality and adjacent quarries have provided key evidence of vertebrate diversity during the latest Cretaceous, yet until recently the Maastrichtian type area had revealed no important insights into the evolutionary history of birds, one of the world’s most conspicuous groups of extant tetrapods. With the benefit of high-resolution micro-CT scanning, two important avian fossils from the Maastrichtian type area have now been examined in detail, offering profound, complementary insights into the evolutionary history of birds. The holotype specimens of these new taxa, Janavis finalidens Benito, Kuo, Widrig, Jagt and Field, 2022, and Asteriornis maastrichtensis Field, Benito, Chen, Jagt and Ksepka, 2020, were originally collected in the late 1990s, but were only investigated in detail more than twenty years later. Collectively, Janavis and Asteriornis provide some of the best evidence worldwide regarding the factors that influenced stem bird extinction and crown bird survivorship through the Cretaceous-Palaeogene transition, as well as insights into the origins of key anatomical features of birds such as an extensively pneumatised postcranial skeleton, a kinetic palate, and a toothless beak. Asteriornis also provides scarce evidence of a Cretaceous-aged divergence time calibration within the avian crown group, while together, Janavis and Asteriornis constitute the only documented co-occurrence of crown birds and non-neornithine avialans. Here, we review key insights into avian evolutionary history provided by these discoveries from the Maastrichtian stratotype, document undescribed and newly discovered Maastrichtian fossils potentially attributable to Avialae and provide the first histological data for the holotype of Asteriornis, illustrating its skeletal maturity at the time of its death.

Trace fossils from the Maastrichtian chalk of the Isle of Rügen, north-east Germany

Dirk Knaust, Hilmar Schnick — Mon, 13 May 2024 00:00:00 -0700

The lower Maastrichtian chalk of the Isle of Rügen was deposited in a pelagic setting in the aphotic zone. Its rich fossil content has attracted research attention for centuries, whereas its ichnological characteristics remain poorly understood, even though horizons with intense bioturbation and occurrences of trace fossils in flint are common. The enhanced colour contrast of smooth chalk faces reveals repeated phases of benthic colonisation; larger burrows are commonly subject to silicification, while flint nodules also can preserve burrows in chalk. A total of 37 ichnogenera, including 47 ichnospecies of bioturbation and bioerosion trace fossils have been recognised; these are here briefly described, in addition to indeterminate material. Many ichnotaxa are recorded for the first time from the Rügen chalk. Bioerosion is restricted mainly to local hardgrounds in the form of biogenic components (such as shells and belemnite guards).

Cross-border correlations showing diachronous lithostratigraphic units in the southeastern North Sea Basin during the Early Oligocene (middle-late Rupelian)

Dirk K. Munsterman, Jef Deckers — Mon, 13 May 2024 00:00:00 -0700

Wireline log correlation panels of palynologically analysed boreholes illustrate lateral facies transitions within Rupelian age strata of the Dutch Rupel Formation across the southeastern North Sea Basin. The middle to upper part of the Rupel Formation consists of clays and silts of the Boom Member and the overlying sandier Steensel Member. In the Mill and Goirle boreholes in the Dutch Province of North Brabant, the Boom Member is thickly developed and represents the middle to upper Rupelian (biozones NSO3 to NSO5a), while the Steensel Member is rather thinly developed and only comprises the uppermost Rupelian (biozone NSO5a). Borehole log correlations show that towards the south (or more proximal to the palaeo-continent) the Rupel Formation becomes sandier and the clayey Boom Member thins in favour of the sandy superjacent Steensel Member. Palynological analyses confirm that the Boom Member is restricted to the middle Rupelian (biozone NSO3) age here, and that the superjacent Steensel Member is of middle to upper Rupelian age (biozones NSO3 to NSO5a). Geological models constructed for northern Belgium propose that this facies transition occurs rather sharply, along a WSW-ENE oriented zone parallel to the presumed shoreline at that time. The results of this study support this interpretation and extend the trend towards the Netherlands.

The diversity of teleost fishes during the terminal Cretaceous and the consequences of the K/Pg boundary extinction event – CORRIGENDUM

Werner W. Schwarzhans, Giorgio Carnevale, Gary L. Stringer — Thu, 16 May 2024 00:00:00 -0700

The authors would like to correct an error in figure 5. The correct figure is available below.

The authors apologise for the error.

Figure 5. Stratigraphical ranges of ophidiiform lineages across the Late Cretaceous and Paleocene. Skeletal reconstruction is Carnevale & Johnson (2015); drawings of extant fishes are from Markle & Olney (1990), Nielsen (1995), Böhlke & Robins (1959) and Schwarzhans et al. (2005); otoliths are from Schwarzhans (2003) and Schwarzhans & Stringer (2020) and ongoing research.