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Noble gases in micrometeorites from the Transantarctic Mountains
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The bulk of extraterrestrial matter currently accreted by the Earth is in the form of micrometeorites (MMs) and interplanetary dust particles (IDPs), thus they may have collectively made a substantial contribution to the volatile inventory of the Earth and the other terrestrial planets. We have performed a complete noble gas study, accompanied by a complete petrographic characterization, of MMs from the Transantarctic Mountain (TAM) collection in the size range ∼300 to ∼1000 µm that fell over an extended time period during the last ∼1 Ma. Our noble gas study includes krypton and xenon, which have been largely missing in previous work. Helium and neon are dominated by a solar component, with generally lower abundance in scoriaceous MMs than in unmelted ones, and also generally lower in abundance than in previously studied MMs, which may be explained by the larger particle size (surface/volume ratio) of the MMs we studied. Considering an enhanced MM flux in the early Solar System, such MMs may have supplied a significant fraction of Earth’s neon. A number of MMs have kept what was probably their pre-terrestrial He/Ne ratio, from which we infer that the observed solar component is retained in a tiny surface region not affected by atmospheric entry. The abundances of (volume-correlated) heavier gases are similar to what was found in previous studies of smaller MMs. While Ar contains both solar and “planetary” contributions, the heavy noble gases (Kr, Xe) generally show “planetary” patterns but are often also compromised by terrestrial contamination as evidenced by an enhanced Kr/Xe ratio. Kr and Xe in a subset of scoriaceous MMs are dominated by isotopically fractionated air, possibly acquired during the passage through Earth’s ionosphere. Those not obviously affected by air show isotopic ratios similar to primitive meteorites (the Q component), thus primordial heavy gases supplied to the Earth by MMs are likely as those found in macroscopic meteorites. There is no evidence for the presence of a “cometary” Xe component as identified in the coma of comet 67P/Churyumov-Gerasimenko, hence a cometary source for a significant fraction of MMs in the studied size range is unlikely. Cosmogenic helium, neon and argon were detected in several cases. Cosmic ray exposure ages were calculated based on cosmogenic 21Ne in combination with the Poynting-Robertson effect, but depend on assumptions about atmospheric entry loss. Still, several cases are consistent with an origin from the asteroid belt (even assuming no loss) and one scoriaceous MM (#45b.17) would have to originate from beyond Jupiter. In at least two cases, including #45b.17, the isotopic composition of cosmogenic Ne appears to be inconsistent with predominant production in small particles free-floating in space, however; much of the irradiation of these MMs may have occurred when they were part of larger parent bodies.
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RBINS Staff Publications 2018
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Nonreceding hare lines: genetic continuity since the Late Pleistocene in European mountain hares (Lepus timidus)
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RBINS Staff Publications 2017
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Normal growth, altered growth? Study of the relationship between harris lines and bone form within a post-medieval plague cemetery (Dendermonde, Belgium, 16th Century).
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Objectives Harris lines (HLs) are defined as transverse, mineralized lines associated with temporary growth arrest. In paleopathology, HLs are used to reconstruct health status of past populations. However, their etiology is still obscure. The aim of this article is to test the reliability of HLs as an arrested growth marker by investigating their incidence on human metrical parameters. Methods The study was performed on 69 individuals (28 adults, 41 subadults) from the Dendermonde plague cemetery (Belgium, 16th century). HLs were rated on distal femora and both ends of tibiae. Overall prevalence and age-at-formation of each detected lines were calculated. ANOVA analyses were conducted within subadult and adult samples to test if the presence of HLs did impact size and shape parameters of the individuals. Results At Dendermonde, 52% of the individuals had at least one HL. The age-at-formation was estimated between 5 and 9 years old for the subadults and between 10 and 14 years old for the adults. ANOVA analyses showed that the presence of HLs did not affect the size of the individuals. However, significant differences in shape parameters were highlighted by HL presence. Subadults with HLs displayed slighter shape parameters than the subadults without, whereas the adults with HLs had larger measurements than the adults without. Conclusions The results suggest that HLs can have a certain impact on shape parameters. The underlying causes can be various, especially for the early formed HLs. However, HLs deposited around puberty are more likely to be physiological lines reflecting hormonal secretions.
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RBINS Staff Publications 2016
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Northern pygmy right whales highlight Quaternary marine mammal interchange
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RBINS Staff Publications 2017
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Note on a highly diverse rotifer assemblage (Rotifera: Monogononta) in a Laotian rice paddy and adjacent pond
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During August 1999, the authors conducted a sampling campaign in the PDR Laos, in order to contribute to the chorology of rotifers in the region. Two samples, collected from a rice paddy and an adjacent pond near Vientiane, Laos, contained a total of 135 rotifer species including several that appear new to science or that warrant taxonomical or biogeographical comments. No new species can be named, but Cephalodella boettgeri KOSTE and Floscularia armata SEGERS are recorded for the second time ever after their description from South America, and Parencentrum lutetiae (HARRING and MYERS) and Polyarthra luminosa KUTIKOVA are new to Southeast Asia. This raises the number of rotifers recorded from Laos from 9 to 130. The diversity recorded is remarkable, especially when compared with that of similar habitats in the Thai part of the floodplain of River Mekong and its tributaries. Different agricultural practices may account for the difference in species richness. Similar highly diverse rotifer faunas are known to occur in natural, tropical and subtropical floodplain systems only. This accords with the view that rice paddies can be regarded as artificial wetlands or floodplain systems, which, if managed taking biodiversity concerns into account, may have a potential for the conservation of freshwater biodiversity. © 2007 Wiley-VCH Verlag GmbH & Co. KGaA.
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RBINS Staff Publications
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Note on the egg productivity of females of Callipogon (Eoxenus) relictus Semenov-Tian-Shanskij, 1899, and first record for Inner Mongolia Autonomous Region in China (Coleoptera, Cerambycidae, Prioninae)
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RBINS Staff Publications
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Note sur les couches de base de la Formation du Panisel entre Torhout et Tielt
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RBINS Staff Publications 2016
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Notes on a small collection of Prioninae from North-East Madagascar with the description of a new Schizodontus Quentin & Villiers, 1974 (Cerambycidae, Closterini)
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RBINS Staff Publications 2021
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Notes on the genus Sarmydus Pascoe, 1867 (Cerambycidae: Prioninae: Anacolini) from India with description of a new species
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RBINS Staff Publications 2020
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Notes on the myrmecophilous spider Mastigusa arietina (Thorell, 1871)
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We provide records of the rarely detected ant-associated spider Mastigusa arietina (Thorell, 1871) in northwest Belgium and discuss how to locate and capture this spider. We show that this myrmecophilous spider is much more common than currently presumed but it is often missed in common spider surveys due to its obligate association with ant nests. We also summarise and illustrate the recently gained insights into its ecology, behaviour, and interactions with its host and other ant associates.
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RBINS Staff Publications 2022
