The Natural History Museum repository: Recent submissions
Now showing items 1-20 of 1294
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An evaporite sequence from ancient brine recorded in Bennu samplesAbstract: Evaporation or freezing of water-rich fluids with dilute concentrations of dissolved salts can produce brines, as observed in closed basins on Earth<jats:sup>1</jats:sup> and detected by remote sensing on icy bodies in the outer Solar System<jats:sup>2,3</jats:sup>. The mineralogical evolution of these brines is well understood in regard to terrestrial environments<jats:sup>4</jats:sup>, but poorly constrained for extraterrestrial systems owing to a lack of direct sampling. Here we report the occurrence of salt minerals in samples of the asteroid (101955) Bennu returned by the OSIRIS-REx mission<jats:sup>5</jats:sup>. These include sodium-bearing phosphates and sodium-rich carbonates, sulfates, chlorides and fluorides formed during evaporation of a late-stage brine that existed early in the history of Bennu’s parent body. Discovery of diverse salts would not be possible without mission sample return and careful curation and storage, because these decompose with prolonged exposure to Earth’s atmosphere. Similar brines probably still occur in the interior of icy bodies Ceres and Enceladus, as indicated by spectra or measurement of sodium carbonate on the surface or in plumes<jats:sup>2,3</jats:sup>.
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An overview of the petrography and petrology of particles from aggregate sample from asteroid BennuAbstract: The OSIRIS‐REx mission returned a sample of regolith from the carbonaceous asteroid Bennu in September 2023. We present preliminary in situ investigations of the petrology and petrography of selected particles ranging in size from 0.5 to 3 mm. Using a combination of optical and electron beam techniques, we investigate whole specimens and polished sections belonging to morphologically and visually distinct categories of particles. We find that morphological differences in the particles are reflective of petrographic and petrologic differences, leading to the conclusion that we have at least two distinct major lithologies in the bulk sample. Our findings support predictions from remote sensing, suggesting that the morphological differences observed in the boulder population of Bennu correspond to petrologic differences. Our data provide insight into the geologic activity on Bennu's parent body and the petrographic framework needed to contextualize the detailed analyses of this pristine asteroidal material.
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Origin of the Jadar Volcano-Sedimentary Li-B Deposit, SerbiaAbstract: The Jadar deposit (Serbia) is a unique end member of the volcano-sedimentary Li deposit class, where the main ore mineral is jadarite (LiNaSiB3O7(OH)), to date only recorded at the Jadar locality. We provide the first account of the features of the Jadar deposit based on the study of drill hole material, complemented by petrographic analysis, whole-rock, and isotopic geochemistry. The Li-B mineralization is hosted by sediments interlayered with tuffs that were deposited in a fault-bounded lacustrine basin. Mineralization processes initially involved alteration of volcanic glass through near-neutral and heated meteoric fluids, which resulted in the formation of hectorite. Lithium clays were later overprinted by higher-pH brines, which underwent significant evaporation, combined with conditions of Na+ and SiO2(aq) saturation, resulting in formation of siliceous gels that were the precursors to jadarite formation and extensive zeolitization of the intrabasinal sediments. Formation of jadarite occurred in two stages: (1) early diagenesis accompanied by zeolitization and precipitation of primary dolomite, which resulted in the sediment-hosted Li mineralization, (2) late remobilization of Li(B-Na)–saturated fluids, leading to formation of epigenetic jadarite-albite infills of fractured rocks. Isotopic geochemistry combined with mineral chemistry proxies indicate that early mineralizing processes were largely dominated by diagenetic fluids that experienced a thermal influence from the coeval cooling of the Miocene S-type granite member of the nearby Cer Mountain Complex. Late thermal maturation of organic matter then resulted in acidic fluids that dissolved the early ore assemblage and led to formation of late diagenetic lithiophosphate and low-Na borates.
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Coastal seawater turbidity and thermal stress control growth of reef-building Porites spp. corals in FijiNearshore reefs, at the interface of land-sea interactions, provide essential ecosystem services, but are susceptible to multiple global and local stressors. These stressors can detrimentally impact coral growth and the continuity of the reef framework. Here, we analyse coral growth records (1998 – 2016) of massive <jats:italic>Porites</jats:italic> spp. colonies from nearshore reefs in Fiji. Our aim is to assess the role of thermal stress and turbidity on coral growth across a range of environments. Our findings reveal a negative linear relationship between linear extension and seawater turbidity across locations (GLM, R<jats:sup>2</jats:sup> = 0.42, <jats:italic>p</jats:italic> < 0.001), indicating that average coral growth is significantly influenced by local environmental conditions. On interannual timescales, all locations experienced a 14% to 30% decrease in linear extension in response to acute thermal stress during the 2013 – 2016 period. This finding highlights the existence of compounding effects between water quality and thermal stress. We suggest that inshore, long-lived massive hard corals in areas of high turbidity are more vulnerable to increasing SSTs due to an already reduced mean growth. Integrated management strategies in these regions that considers managing for multiple, interacting local stressors are warranted to enhance resilience.
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The northernmost known observation of Myrmecophilus acervorum and the first records of Myrmecophilidae (Orthoptera, Ensifera) from LatviaThe first observations of myrmecophilous ant cricket Myrmecophilus acervorum (Panzer, 1799) and the family Myrmecophilidae from Latvia are presented. The observations were made in two locations subject to flooding in springtime. Adult and juvenile female individuals were observed. The discussed records appear to be the northernmost known distribution limit of this species.
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The evolutionary history and timeline of mites in ancient soilsAcariform mites play a crucial role as primary soil decomposers, impacting the carbon cycle. However, the timing of their diversification is uncertain, with estimated dates ranging from the Precambrian (no land plants) to the Carboniferous (diverse terrestrial ecosystems). One factor affecting these time estimates is an uncertain phylogenetic position of the earliest unequivocal fossil mites from the Devonian Rhynie Chert, which have been classified in five modern families and three suborders. Here, we thoroughly examine these specimens, assign them to a single species Protacarus crani (family Protoacaridae, fam. nov., suborder Endeostigmata) and integrate this information into a time-calibrated phylogenetic analysis. Our phylogeny suggests a Cambrian basal divergence of Acariformes (508-486 Ma), coinciding with the land colonization by bryophytes. At this time, the mites' ecological niches were probably diversified beyond the upper soil. Our study provides temporal context, improves the accuracy of fossil dating, and underscores the importance of mites' diverse habitats and their potential roles in soil food webs.
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Gregarious behaviour in Carboniferous cyclidan crustaceansGregarious behaviours in modern and fossil arthropods are commonly associated with defensive strategies, mass moulting and synchronous reproduction. Such behaviour is scarcely documented in the crustacean fossil record. Identifying clusters in extinct Pancrustacea is, therefore, important for understanding the evolutionary history and origin of crustacean gregariousness. Cyclida, an order of extinct, enigmatic pancrustaceans that have been subject to limited palaeoecological examination, represents an ideal group for testing the presence of gregarious behaviour. Here, we report a cluster of 50 <jats:italic>Schramine montanaensis</jats:italic> individuals from the Serpukhovian-aged Bear Gulch Limestone of Montana, USA, expanding the exceptionally rare record of cyclidan aggregations. The presence of articulated specimens with appendages and possible gill preservation supports the interpretation of carcasses that were preserved during a rapid burial event. We propose that this cluster records either a mass moulting event or clustering for shelter, representing one of the oldest records of crustacean gregariousness. These findings provide important insights into cyclidan life modes and ecological interactions in Carboniferous marine environments.
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Semi‐quantitative characterisation of mixed pollen samples using MinION sequencing and Reverse Metagenomics (RevMet)The ability to identify and quantify the constituent plant species that make up a mixed‐species sample of pollen has important applications in ecology, conservation, and agriculture. Recently, metabarcoding protocols have been developed for pollen that can identify constituent plant species, but there are strong reasons to doubt that metabarcoding can accurately quantify their relative abundances. A PCR‐free, shotgun metagenomics approach has greater potential for accurately quantifying species relative abundances, but applying metagenomics to eukaryotes is challenging due to low numbers of reference genomes. We have developed a pipeline, RevMet (Reverse Metagenomics) that allows reliable and semi‐quantitative characterization of the species composition of mixed‐species eukaryote samples, such as bee‐collected pollen, without requiring reference genomes. Instead, reference species are represented only by ‘genome skims’: low‐cost, low‐coverage, short‐read sequence datasets. The skims are mapped to individual long reads sequenced from mixed‐species samples using the MinION, a portable nanopore sequencing device, and each long read is uniquely assigned to a plant species. We genome‐skimmed 49 wild UK plant species, validated our pipeline with mock DNA mixtures of known composition, and then applied RevMet to pollen loads collected from wild bees. We demonstrate that RevMet can identify plant species present in mixed‐species samples at proportions of DNA ≥ 1%, with few false positives and false negatives, and reliably differentiate species represented by high versus low amounts of DNA in a sample. RevMet could readily be adapted to generate semi‐quantitative datasets for a wide range of mixed eukaryote samples. Our per‐sample costs were £90 per genome skim and £60 per pollen sample, and new versions of sequencers available now will further reduce these costs.
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Nanopore adaptive sampling: a tool for enrichment of low abundance species in metagenomic samplesAdaptive sampling is a method of software-controlled enrichment unique to nanopore sequencing platforms. To test its potential for enrichment of rarer species within metagenomic samples, we create a synthetic mock community and construct sequencing libraries with a range of mean read lengths. Enrichment is up to 13.87-fold for the least abundant species in the longest read length library; factoring in reduced yields from rejecting molecules the calculated efficiency raises this to 4.93-fold. Finally, we introduce a mathematical model of enrichment based on molecule length and relative abundance, whose predictions correlate strongly with mock and complex real-world microbial communities.
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Facilitating high throughput collections-based genomics: a comparison of DNA extraction and library building methodsWhile DNA barcoding methods are an increasingly important tool in biological conservation, the resource requirements of constructing reference libraries frequently reduce their efficacy. One efficient way of sourcing taxonomically validated DNA for reference libraries is to use museum collections. However, DNA degradation intrinsic to historical museum specimens can, if not addressed in the wet lab, lead to low quality data generation and severely limit scientific output. Several DNA extraction and library build methods that are designed to work with degraded DNA have been developed, although the ability to implement these methods at scale and at low cost has yet to be formally addressed. Here, the performance of widely used DNA extraction and library build methods are compared using museum specimens. We find that while our selected DNA extraction methods do not significantly differ in DNA yield, the Santa Cruz Reaction (SCR) library build method is not only the most effective at retrieving degraded DNA from museum specimens but also easily implemented at high throughput for low cost. Results highlight the importance of lab protocol on data yield. An optimised “sample to sequencing” high-throughput protocol which incorporates SCR is included to allow for easy uptake by the wider scientific community.
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A new euarthropod from the Soom Shale (Ordovician) Konservat‐Lagerstätte, South Africa, with exceptional preservation of the connective endoskeleton and myoanatomyA new exceptionally preserved euarthropod, Keurbos susanae gen. et sp. nov. from the Upper Ordovician Soom Shale Konservat‐Lagerstätte of South Africa, is described herein. Two specimens exhibit an unusual preservation style such that the cuticular exoskeleton is preserved in low relief but retains high‐fidelity details, whereas the internal anatomy is preserved in three dimensions and includes myoanatomy and aspects of the connective inter‐ and intrasegmental endoskeleton. The trunk has 46 homonomous segments and tapers towards the posterior. The dorsal surface comprises the posterior margins of tergites that form rounded paratergal folds at their lateral margins. Sternal morphology is seen from an internal view of the fossils and includes axial sternites and associated ovoid plates, both with fringing setae along their posterior margins. Patchy, incomplete preservation of the appendages is consistent with the ‘reversed’ taphonomy of these fossils in which sclerotized elements that project beyond the body margin, such as lamellae with vascular channels and pits, are preserved, whereas those inside the body margins are absent or poorly expressed. Euarthropod characters include an arthrodized tergal and sternal exoskeleton, and a segmental connective endoskeleton. Recent depopulation of the euarthropod stem group has witnessed conspicuously arthrodized fossils formerly placed in the stem group being shifted into the crown, increasing the likelihood that <jats:italic>Keurbos</jats:italic> is likewise a crown‐group euarthropod. Comparison with a phylogenetically disparate suite of similarly homonomous, multisegmented taxa indicates no convincing synapomorphies. The grouping of relevant middle Palaeozoic exemplars as ‘enantiopod’ pancrustaceans could suggest that Keurbos might be allied.
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The problems of resolving historical specimen data, focusing on a specimen of Myotis austroriparius (Mammalia, Chiroptera, Vespertilionidae) collected by Thomas DrummondThe geographical itineraries of Thomas Drummond’s two separate expeditions to Canada (1825–1827) and the United States of America (1831–1835) are used to provide historical context for the specimens collected and their localities. The coordinates for these locations are estimated and their geographical positions mapped. The difficulties of resolving various problems with historical specimens are explored and several examples are provided, including the contentious origin and identification of a southeastern myotis, Myotis austroriparius (Rhoads, 1897) (NHMUK 1837.4.8.127). Information about type specimens is discussed and the geographical position of several type localities of rodents and a mustelid in the Rocky Mountains and a lagomorph in the USA are refined.
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Secrets of a Silent Miniaturist: Findings from a Technical Study of Miniatures Attributed to Isaac OliverAn evidently accomplished draughtsman, Isaac Oliver (circa 1565–1617) remains an enigmatic artist in many respects. While Nicholas Hilliard’s treatise on the art of limning provides considerable insight into his material use, techniques, and self-perception, no equivalent documentary evidence survives from Oliver’s hand, and many questions regarding his training, approach, and oeuvre have yet to be answered. This article presents key findings from the collaborative and technically focused research project “Secrets of a Silent Miniaturist: Technical Analysis of Isaac Oliver’s Miniatures”, undertaken by the Fitzwilliam Museum and the Hamilton Kerr Institute in Cambridge (UK). The project aims to shed light on Oliver’s artistic practice through the detailed, technical study of a representative selection of his surviving miniatures, investigated through an up-to-date, non-invasive analytical and technical lens. The article discusses the discovery of near-invisible changes to compositions implemented during the initial execution, differences in execution and later history between two versions of a portrait of Henry Frederick Prince of Wales, the first identification in a miniature of a rare mercury-based white pigment whose deterioration led to later campaigns of repainting, and the use of a hitherto unacknowledged range of pigments and media in Oliver’s landscape miniatures that raises further questions about Oliver’s connection with artistic traditions on the Continent.
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New evidence for the intentional use of calomel as a white pigmentIn this work, we report the results of the in situ application of micro‐Raman spectroscopy to the analysis of two historic painted objects: a 15th‐century illuminated manuscript and a late 16th‐century portrait miniature. Both objects were unexpectedly found to contain calomel (Hg<jats:sub>2</jats:sub>Cl<jats:sub>2</jats:sub>), intentionally used as a white pigment. Calomel was a widespread and popular medicine until it fell out of use at the end of the 19th century due to its toxicity, and a material called ‘mercury white’ is referred to in 16th‐century technical literature on painting. However, although calomel has been recognised in the past as a degradation product of cinnabar in both wall and easel paintings, its deliberate use as a pigment on cultural heritage objects has only been documented recently in white areas painted on 17th‐century South American objects. The present study describes the first ever verified use of calomel as a white pigment on European works of art, both of which predate its documented use in South America.
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Non-Invasive Technical Investigation of English Portrait Miniatures Attributed to Nicholas Hilliard and Isaac OliverThis study presents the results of the technical investigation carried out on several English portrait miniatures painted in the 16th and 17th century by Nicholas Hilliard and Isaac Oliver, two of the most famous limners working at the Tudor and Stuart courts. The 23 objects chosen for the analysis, spanning almost the entire career of the two artists, belong to the collections of the Victoria and Albert Museum (London) and the Fitzwilliam Museum (Cambridge). A non-invasive scientific methodology, comprising of stereo and optical microscopies, Raman microscopy, and X-ray fluorescence spectroscopy, was required for the investigation of these small-scale and fragile objects. The palettes and working techniques of the two artists were characterised, focusing in particular on the examination of flesh tones, mouths, and eyes. These findings were also compared to the information written in the treatises on miniature painting circulating during the artists’ lifetime. By identifying the materials and techniques most widely employed by the two artists, this study provides information about similarities and differences in their working methods, which can help to understand their artistic practice as well as contribute to matters of attribution.
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Use of standard analytical tools to detect small amounts of smalt in the presence of ultramarine as observed in 15th-century Venetian illuminated manuscriptsA previous preliminary study of 15th-century Venetian manuscript fragments by the Master of the Murano Gradual identified the presence of cobalt in many ultramarine blue areas, suggesting the presence of smalt. This would represent an early use of this glassy pigment in Venetian illuminated manuscripts. Whereas sampling has been used to identify smalt in 15th century paintings, only non-invasive methods can be used on manuscripts due to their small size and fragile nature. Here we investigated four non-invasive analysis techniques to identify small amounts of smalt in the presence of ultramarine, including single-point and scanning XRF spectroscopy, UV–vis-NIR-SWIR reflectance spectroscopy (FORS), Raman spectroscopy, and external reflection FT-IR spectroscopy. This was done by studying paint mock-ups of ultramarine and smalt mixtures with and without the presence of a white pigment on parchment. The results showed molecular spectroscopy techniques (reflectance, Raman, and FTIR) require at least ~ 30–40% smalt by percent mass when in the presence of ultramarine in order to detect its presence, whereas elemental XRF spectroscopy can detect cobalt (and thus infer the presence of smalt) at the ~ 1% level. To further explore the inference of smalt by XRF, additional XRF analysis was conducted to specifically look for elements associated with cobalt minerals (i.e. nickel, arsenic, bismuth, etc.). High spatial resolution XRF scanning (60–100 μm X-ray spot size) was used to look for cobalt in smalt particles which are typically larger than those of ultramarine. These two XRF analysis approaches worked well with the mock-up paint samples, and were subsequently applied to the manuscripts for which molecular spectroscopy methods yielded no unambiguous evidence for smalt. The data underscore the challenges of conclusively identifying smalt in complex paint systems when samples are not available, but do suggest that the Master of the Murano illuminated manuscript fragments contain smalt, but perhaps not in a form or amount researchers are used to seeing in paintings.
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A revision of the type locality of Black-throated Accentor Prunella atrogularis huttoni (Moore)We examine the type locality of Black-throated Accentor Prunella atrogularis huttoni that is listed as ‘ranges above Simla’ and propose a revision of the same to ‘Afghanistan’
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First evidence of attached juveniles in the solutan echinoderm Pahvanticystis from the middle Cambrian Weeks Formation (Utah, USA)The fossil record of the Palaeozoic echinoderm class Soluta suggests they originated in the Miaolingian (middle Cambrian) of Laurentia as permanently attached suspension feeders, demonstrating a stepwise shift towards vagility in successive strata. Here, we report a new specimen of Pahvanticystis cf. utahensis associated with three putative juveniles interpreted as belonging to the same species. We interpret this as evidence of facultative attachment in juveniles of Pahvanticystis, which had not previously been reported in this taxon, but is known in the earlier genus Castericystis. Our findings indicate that attachment as a juvenile was more widespread in solutans than previously thought.