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Experimental metamorphosis of Halisarca dujardini larvae (Demospongiae, Halisarcida): Evidence of flagellated cell totipotentiality
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The potency of flagellated cells of Halisarca dujardini (Halisarcida, Demospongiae) larvae from the White Sea (Arctic) was investigated experimentally during metamorphosis. Two types of experiments were conducted. First, larvae were maintained in Ca2+ free seawater (CFSW) until the internal cells were released outside through the opening of the posterior pole. These larvae that only composed of flagellated cells (epithelial larvae) were then returned to sea water (SW) to observe their metamorphosis. The posterior aperture closed before they settled on a substratum and started a metamorphosis similar to intact larvae. Secondly, epithelial larvae were, first, further treated in CFSW and then mechanically dissociated. Separated cells or groups of cells were returned to SW, where they constituted large friable conglomerates. After 12-17 h in SW, flagellated cells showed the first steps of dedifferentiation, and regional differentiation was noticeable within conglomerates after approximately 24-36 h. External cells differentiated into pinacocytes while internal cells kept their flagella and became united in a layer. Within 48-72 h, internal cells of the conglomerates formed spherical or ovoid clusters with an internal cavity bearing flagella. These clusters further fused together in a rhagon containing one or two large choanocyte chambers. The sequence of cellular processes in epithelial larvae and in flagellated cell conglomerates was similar. Previous observations indicating the totipotentiality of larval flagellated cells during normal metamorphosis of H. dujardini are thus confirmed. © 2007 Wiley-Liss, Inc.
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RBINS Staff Publications
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Experiments on tsunami induced boulder transport – A review
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RBINS Staff Publications 2021
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Explaining Uncertainty Avoidance in Meciaprojects: Resource Constraints, Strategic Behaviour, or Institutions?
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RBINS Staff Publications 2021
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Exploring Biological and Ecological Components of Sheep Astragalus Size and Shape Variation Using 3D Geometric Morphometrics: Towards A Bioarchaeological Proxy
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One of the key challenges in the archaeology of sheep domestication is reconstructing the complex history of environmental and anthropogenic transformations undergone by sheep since the beginning of the domestication process of their wild ancestors. In recent years, GMM studies of sheep astragalus bones have contributed to our understanding of morphological differences between wild and domestic caprine species. However, the respective influences of biological and ecological factors on astragalus morphological variations in sheep remain poorly documented. This limitation hinders a comprehensive understanding of its biosystematic resolution and, consequently, its use as a proxy in archaeological contexts to investigate early selective breeding and the emergence of sheep breeds in Southwest Asia. This paper presents the results of a morphological study of 96 astragali using 3D geometric morphometrics, focusing primarily on modern Eurasian and African sheep breeds and landraces. The study is based on a well-documented comparative collection encompassing phenotypical traits (breed, sex, age, presence/absence of horns, coat and tail type, weight, body length); ecological characteristics (climate, geography, environment, elevation, topography); and breeding strategies (mobility). The results demonstrate that the 3D astragalus morphological pattern is a reliable marker for distinguishing one sheep breed from another. They suggest that astragalus morphology is only slightly influenced by phenotypic markers. The study further explores the effects of environmental and climatic factors on phenotypic variation and highlights the potential of the astragalus as an ecomorphological marker. Finally, the current limitations in interpreting the relationship between astragalus morphological variation and mobility strategies in archaeological contexts are discussed.
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RBINS Staff Publications 2026
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Exploring hidden parasite diversity with environmental DNA metabarcoding during a ParasiteBlitz across a coastal habitat gradient
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Environmental DNA (eDNA) metabarcoding has lagged in parasite biodiversity assessments. We implemented this method to examine parasite diversity in sediment and water from 4 physically connected aquatic habitats in coastal South Carolina, USA, as part of a ParasiteBlitz in April 2023. Sediment was collected using a syringe corer, and water was sampled using active filtration and passive collection. Five amplicon libraries, using primers targeting portions of the mitochondrial COI of platyhelminths and 18S ribosomal RNA genes of nematodes, myxozoans, microsporidians, and protists, successfully yielded parasite sequences. Out of >5.8 million sequences, we identified >1,000 parasite amplicon sequence variants (ASVs) corresponding to ~600 parasite operational taxonomic units, from 6 parasite groups. Most diversity was observed among the microsporidians, whose assay demonstrated the highest fidelity. Actively-filtered water samples captured ASVs of all 6 groups, whereas sediment captured only 4, despite yielding 3× as many ASVs. Low DNA yields from passive water samples resulted in fewer, but some unique, ASVs representing 3 parasite groups. The most efficient sampling method varied with respect to parasite group across habitats, and the parasite communities from each habitat were distinct regardless of sampling method. We detected ASVs of 9 named species, 4 of which may represent introductions to the US. The abundance of our results demonstrates the effectiveness and efficiency of eDNA metabarcoding for assessing parasite diversity during short, intensive surveys, and highlights the critical need for more comprehensive sequence databases and the development of primers for those parasite taxa that elude detection using eDNA methods.
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RBINS Staff Publications 2025
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Exploring sexual dimorphism of human occipital and temporal bones through geometric morphometrics in an identified Western-European sample
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Abstract Sex estimation is a paramount step of bioprofiling in both forensic anthropology and osteoarchaeology. When the pelvis is not optimally preserved, anthropologists commonly rely on the cranium to accurately estimate sex. Over the last decades, the geometric morphometric (GM) approach has been used to determine sexual dimorphism of the crania, in size and shape, overcoming some difficulties of traditional visual and metric methods. This article aims to investigate sexual dimorphism of the occipital and temporal region through GM analysis in a metapopulation of 50 Western-European identified individuals. Statistical analyses were performed to compare centroid size and shape data between sexes through the examination of distinct functional modules. Regression and Procrustes ANOVA were used to examine allometric and asymmetrical implications. Discriminant functions, combining size and shape data, were established. Significant dimorphism in size was found, with males having larger crania, confirming the major influence size has on cranial morphology. Allometric relationships were found to be statistically significant in both right and left temporal bones while shape differences between sexes were only significant on the right temporal bone. The visualization of the mean consensus demonstrated that males displayed a larger mastoid process associated with a reduced mastoid triangle and less projected occipital condyles. This exploratory study confirms that GM analysis represents an effective way to quantitatively capture shape of dimorphic structures, even on complex rounded ones such as the mastoid region. Further examination in a larger sample would be valuable to design objective visualization tools that can improve morphoscopic sex estimation methods.
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RBINS Staff Publications 2022
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Exploring species level taxonomy and species delimitation methods in the facultatively self-fertilizing land snail genus Rumina (Gastropoda: Pulmonata)
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RBINS Staff Publications
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Exploring the bushmeat market in Brussels, Belgium: a clandestine luxury business
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RBINS Staff Publications 2021
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Exploring the shell-based taxonomy of the Sri Lankan land snail Corilla H. and A. Adams, 1855 (Pulmonata: Corillidae) using mitochondrial DNA
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RBINS Staff Publications 2017
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Exploring the use of Cytochrome Oxidase c Subunit 1 (COI) for DNA barcoding of free-living marine nematodes
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Background: The identification of free-living marine nematodes is difficult because of the paucity of easily scorable diagnostic morphological characters. Consequently, molecular identification tools could solve this problem. Unfortunately, hitherto most of these tools relied on 18S rDNA and 28S rDNA sequences, which often lack sufficient resolution at the species level. In contrast, only a few mitochondrial COI data are available for free-living marine nematodes. Therefore, we investigate the amplification and sequencing success of two partitions of the COI gene, the M1-M6 barcoding region and the I3-M11 partition. Methodology: Both partitions were analysed in 41 nematode species from a wide phylogenetic range. The taxon specific primers for the I3-M11 partition outperformed the universal M1-M6 primers in terms of amplification success (87.8\% vs. 65.8\%, respectively) and produced a higher number of bidirectional COI sequences (65.8\% vs 39.0\%, respectively). A threshold value of 5\% K2P genetic divergence marked a clear DNA barcoding gap separating intra-and interspecific distances: 99.3\% of all interspecific comparisons were 〉0.05, while 99.5\% of all intraspecific comparisons were 〈0.05 K2P distance. Conclusion: The I3-M11 partition reliably identifies a wide range of marine nematodes, and our data show the need for a strict scrutiny of the obtained sequences, since contamination, nuclear pseudogenes and endosymbionts may confuse nematode species identification by COI sequences.
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