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A Tale of Three Oceans — Taxonomy of the Holothuria (Thymiosycia) arenicola Semper, 1868 complex (Echinodermata: Holoturoidea: Holothuriidae)
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The ubiquitous sea cucumber Holothuria (Thymiosycia) arenicola Semper, 1868, externally characterized by a double row of dark blotches of various sizes on its dorsal body wall and a cryptic behaviour, is generally assumed to have a wide tropical distribution, although it has not been reported from the Eastern tlantic. Careful morphological examination, with emphasis on the ossicle assemblage, of type and non-type H. arenicola specimens sampled in the Indian, Pacific and tlantic Ocean, its subjective synonyms and species with a similar colouration and habit, revealed that H. arenicola is often confused with other species. This paper formally separates the different species in the H. arenicola complex, one of them being a species new to science: Holothuria (Thymiosycia) kerriensis sp. nov. dditionally, we describe two other species that are often confused with H. arenicola: Holothuria (Lessonothuria) gracilis Semper, 1868 and H. (Thymiosycia) strigosa Selenka, 1867. The H. arenicola complex per se is keyed-out, with the ossicle assemblage of the musculature being recognised as an important, previously largely neglected, guide. This contribution highlights the importance of building and curating well-maintaned natural history collections to understand biodiversity through time and space.
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RBINS Staff Publications 2024
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A tardigrade in Dominican amber
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Tardigrades are a diverse group of charismatic microscopic invertebrates that are best known for their ability to survive extreme conditions. Despite their long evolutionary history and global distribution in both aquatic and terrestrial environments, the tardigrade fossil record is exceedingly sparse. Molecular clocks estimate that tardigrades diverged from other panarthropod lineages before the Cambrian, but only two definitive crown-group representatives have been described to date, both from Cretaceous fossil deposits in North America. Here, we report a third fossil tardigrade from Miocene age Dominican amber. Paradoryphoribius chronocaribbeus gen. et sp. nov. is the first unambiguous fossil representative of the diverse superfamily Isohypsibioidea, as well as the first tardigrade fossil described from the Cenozoic. We propose that the patchy tardigrade fossil record can be explained by the preferential preservation of these microinvertebrates as amber inclusions, coupled with the scarcity of fossiliferous amber deposits before the Cretaceous.
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RBINS Staff Publications 2021 OA
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A taste of time. Foodways and cultural practices in Late Achaemenid-Early Hellenistic Düzen Tepe (SW Anatolia)
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RBINS Staff Publications 2017
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A taste of time. Foodways and cultural practices in Late Achaemenid-Early Hellenistic DüzenTepe (SW Anatolia)
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RBINS Staff Publications 2017
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A taxonomic revision of European Herpetocypris BRADY and NORMAN, 1889 (Crustacea, Ostracoda)
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RBINS Staff Publications
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A taxonomic update of the Typhinae (Gastropoda: Muricidae) with a review of New Caledonia species and the description of new species from New Caledonia, the South China Sea and Western Australia
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RBINS Staff Publications 2021
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A techno-economic approach for capacity assessment and ranking of potential options for geological storage of CO2 in Austria
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RBINS Staff Publications 2016
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A temporary exposure of the Late Miocene Deurne Sand Member in Antwerpen (Flanders, Belgium)
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RBINS Staff Publications
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A tight association in genetically unlinked traits in sympatric and allopatric populations of a saltmarsh beetle
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Local adaptation likely involves selection on multiple, genetically unlinked traits to increase fitness in divergent habitats. Conversely, recombination is expected to counteract local adaptation under gene flow by breaking down adaptive gene combinations. Western European populations of the salt marsh beetle Pogonus chalceus are characterized by large interpopulation variation at various geographical ranges in two traits related to dispersal ability, i.e. wing size and different allozymes of the mitochondrial NADP?-dependent isocitrate dehydrogenase (mtIdh) gene. In this study, we tested whether variation in wing length was as strongly genetically determined in locally adapted populations in a sympatric mosaic compared to allopatric populations, and if variation in mtIDH and wing size was genetically unlinked. We demonstrate that the genetic determination of wing size is very high (h2 = 0.90) in sympatry and of comparable magnitude as geographically separated populations. Second, we show that, although frequencies of mtIDH allozymes are tightly associated with mean population wing size across Western European populations, the correlation is strongly reduced within some of the populations. These findings demonstrate that the divergence involves at least two traits under independent genetic control and that the genetically distinct ecotypes are retained at geographical distances with ample opportunity for gene flow.
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RBINS Staff Publications
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A transient deep-sea circulation switch during Eocene Thermal Maximum 2.
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Ever since its discovery, Eocene Thermal Maximum 2 (ETM2; ~53.7 Ma) has been considered as one of the “little brothers” of the Paleocene-Eocene Thermal Maximum (PETM; ~56 Ma) as it displays similar characteristics including abrupt warming, ocean acidification, and biotic shifts. One of the remaining key questions is what effect these lesser climate perturbations had on ocean circulation and ventilation and, ultimately, biotic disruptions. Here we characterize ETM2 sections of the NE Atlantic (Deep Sea Drilling Project Sites 401 and 550) using multispecies benthic foraminiferal stable isotopes, grain size analysis, XRF core scanning, and carbonate content. The magnitude of the carbon isotope excursion (0.85–1.10‰) and bottom water warming (2–2.5°C) during ETM2 seems slightly smaller than in South Atlantic records. The comparison of the lateral δ13C gradient between the North and South Atlantic reveals that a transient circulation switch took place during ETM2, a similar pattern as observed for the PETM. New grain size and published faunal data support this hypothesis by indicating a reduction in deepwater current velocity. Following ETM2, we record a distinct intensification of bottom water currents influencing Atlantic carbonate accumulation and biotic communities, while a dramatic and persistent clay reduction hints at a weakening of the regional hydrological cycle. Our findings highlight the similarities and differences between the PETM and ETM2. Moreover, the heterogeneity of hyperthermal expression emphasizes the need to specifically characterize each hyperthermal event and its background conditions to minimalize artifacts in global climate and carbonate burial models for the early Paleogene.
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