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The first edrioasteroid echinoderm from the lower Cambrian Chengjiang biota of Yunnan Province, China
No full textUntil now, the earliest fossil echinoderms have been predominantly known from the early Cambrian of Laurentia and West Gondwana. Here, we describe Sprinkleoglobus extenuatusgen. et sp. nov. from the Chengjiang biota (Cambrian Series 2, Stage 3) of Yunnan Province, China. The over-all profile of the theca and the morphology of the ambulacra clearly establish it as an edrioasteroid echinoderm. This represents the first discovery of an unequivocal echinoderm from the early part of the Cambrian of South China and is among the oldest records of echinoderms globally. Our material shows that edrioasteroids were diverse and widely distributed from their first occurrence in the fossil record, suggesting an earlier origin for the group. We infer that Sprinkleoglobus and other early echinoderms were adapted for attaching to hard substrates, implying that the so-called Cambrian substrate revolution was not a strong control on the early evolution of attachment in echinoderms.Copyright: © 2022 The Authors. Papers in Palaeontology published by John Wiley & Sons Ltd on behalf of The Palaeontological Association.
This is an open access article under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/), which permits use, distribution and reproduction in any medium, provided the original work is properly cited.NHM Repositor
THEFT FROM THE NATURAL HISTORY MUSEUM’S BIRD COLLECTION - WHAT CAN WE LEARN?
Get PDFDuring the past 100 years, the Natural History Museum has suffered three major specimen thefts from its bird research collections: the removal over many years and relabeling of specimens by Richard MEINERTZHAgEN during the early
and mid 20th century, the major egg theft conducted by Mervyn SHoRTHoUSE during the 1970s and the break-in and removal of just under 300 bird skins by Edwin RIST in 2009. These thefts were carried out in greatly varying manners and with
widely differing apparent motivations. This paper explores these episodes, with the aim of providing museum bird curators with information useful for assessing and addressing the risks to their own collections.The attached file is the published version of the article from the conference proceedings.NHM Repositor
Exites in Cambrian arthropods and homology of arthropod limb branches
Get PDFAbstract: The last common ancestor of all living arthropods had biramous postantennal appendages, with an endopodite and exopodite branching off the limb base. Morphological evidence for homology of these rami between crustaceans and chelicerates has, however, been challenged by data from clonal composition and from knockout of leg patterning genes. Cambrian arthropod fossils have been cited as providing support for competing hypotheses about biramy but have shed little light on additional lateral outgrowths, known as exites. Here we draw on microtomographic imaging of the Cambrian great-appendage arthropod Leanchoilia to reveal a previously undetected exite at the base of most appendages, composed of overlapping lamellae. A morphologically similar, and we infer homologous, exite is documented in the same position in members of the trilobite-allied Artiopoda. This early Cambrian exite morphology supplements an emerging picture from gene expression that exites may have a deeper origin in arthropod phylogeny than has been appreciated.Copyright © The Authors, 2021. This is an open access article, available to all readers online, published under a creative commons licensing (https://creativecommons.org/licenses/by/4.0/). The attached file is the published version of the article.NHM Repositor
The atmospheric entry of fine-grained micrometeorites: The role of volatile gases in heating and fragmentation
Get PDFThe early stages of atmospheric entry are investigated in four large (250–950 lm) unmelted micrometeorites (three fine-grained and one composite), derived from the Transantarctic Mountain micrometeorite collection. These particles have abundant, interconnected, secondary pore spaces which form branching channels and show evidence of enhanced heating along their channel walls. Additionally, a micrometeorite with a doublewalled igneous rim is described, suggesting that some particles undergo volume expansion during entry. This study provides new textural data which links together entry heating processes known to operate inside micrometeoroids, thereby generating a more comprehensive model of their petrographic evolution. Initially, flash heated micrometeorites develop a melt layer on their exterior; this igneous rim migrates inwards. Meanwhile, the particle core is heated by the decomposition of low-temperature phases and by volatile gas release. Where the igneous rim acts as a seal, gas pressures rise, resulting in the formation of interconnected voids and higher particle porosities. Eventually, the igneous rim is breached and gas exchange with the atmosphere occurs. This mechanism replaces inefficient conductive rim-to-core thermal gradients with more efficient particle-wide heating, driven by convective gas flow. Interconnected voids also increase the likelihood of particle fragmentation during entry and, may therefore explain the rarity of large fine-grained micrometeorites among collections.Copyright © 2018, Suttle, M.D. et al. This document is the author’s final accepted version of the journal article. You are advised to consult the published version if you wish to cite from it.NHM Repositor
The Phylogenetics and Biogeography of the Central Asian Hawkmoths, Hyles hippophaes and H. chamyla: Can Mitogenomics and Machine Learning Bring Clarity?
Get PDFThe western Palaearctic species of the hawkmoth genus Hyles (Lepidoptera: Sphingidae) have long been the subject of molecular phylogenetic research. However, much less attention has been paid to the taxa inhabiting the central and eastern Palaearctic, particularly Central Asia, where almost 50% of the species diversity of the genus occurs. Yet, many taxonomic conundrums hinder a proper assessment of the true diversity in these moths. One still unresolved group of species includes Hyles hippophaes and Hyles chamyla. Despite a largely overlapping morphology and ecology, a plethora of infraspecific taxa display some unique divergent characters over a wide geographical area. In this study, we undertook a taxonomic assessment of each population and resolved this species complex using an integrative approach. A combination of new computational techniques (DAISY-II) in comparative morphology and recent advances in DNA extraction methods and sequencing of museum specimens (WISC) alongside more traditional genetic approaches allowed testing of the three main phenotypes—bienerti, chamyla and apocyni—in terms of their morphological, mitochondrial and biogeographical integrity, and to elucidate their evolutionary relationships. Our results support the existence of two closely related species, Hyles chamyla and H. hippophaes, but the former species H. apocyni (here discussed as the ecological form apocyni of H. chamyla) is best regarded as a hybrid between H. chamyla and H. h. bienerti. The results indicate that the evolutionary relationship between H. chamyla and H. hippophaes is one of admixture in the context of ongoing ecological differentiation, which has led to shared morphological characters and a blurring of the species boundaries. These results clarify the evolutionary relationships of this species complex and open future research lines, including the analysis of nuclear markers and denser sampling, particularly of H. hippophaes and H. vespertilio in western Europe.Copyright: © 2021 The Authors. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are creditedNHM Repositor
Stability in Lepidoptera names is not served by reversal to gender agreement: a response to Wiemers et al. (2018)
No full textNoneThis is an open access article, available to all readers online, published under a creative commons licensing (https://creativecommons.org/share-your-work/public-domain/cc0/).NHM Repositor
Temminck's Gallus giganteus; a gigantic obstacle to Darwin's theory of domesticated fowl origin?
Get PDFIn 1813, based on the single foot of a large chicken, Temminck named a ‘new' species of junglefowl, Gallus giganteus. He considered this ‘species’ the ancestor of several large domesticated chicken breeds and believed it was one of six wild ancestral species of domestic fowl. Temminck's hypothesis was rejected by Blyth who thought Red Junglefowl G. gallus was the sole ancestor. The arrival into Britain of several very large Asian chicken breeds in the mid-19th century led to speculation that Temminck's G. giganteus may have been their wild ancestor. Darwin, who had initially agreed with Blyth, noted several peculiarities in the Cochin, a large Asian breed, which he concluded might not have been achieved by selective breeding, and questioned whether G. giganteus was involved in their ancestry. Temminck's giant junglefowl appeared to be a significant hurdle for Darwin in his effort to prove a single ancestral origin for domestic chickens.© 2020 The Authors; This is an open-access article distributed under the terms of the Creative Commons Attribution-NonCommercial Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.NHM Repositor
Vertically migrating Isoxys and the early Cambrian biological pump
No full textThe biological pump is crucial for transporting nutrients fixed by surface-dwelling primary producers to demersal animal communities. Indeed, the establishment of an efficient biological pump was likely a key factor enabling the diversification of animals over 500 Myr ago during the Cambrian explosion. The modern biological pump operates through two main vectors: the passive sinking of aggregates of organic matter, and the active vertical migration of animals. The coevolution of eukaryotes and sinking aggregates is well understood for the Proterozoic and Cambrian; however, little attention has been paid to the establishment of the vertical migration of animals. Here we investigate the morphological variation and hydrodynamic performance of the Cambrian euarthropod Isoxys. We combine elliptical Fourier analysis of carapace shape with computational fluid dynamics simulations to demonstrate that Isoxys species likely occupied a variety of niches in Cambrian oceans, including vertical migrants, providing the first quantitative evidence that some Cambrian animals were adapted for vertical movement in the water column. Vertical migration was one of several early Cambrian metazoan innovations that led to the biological pump taking on a modern-style architecture over 500 Myr ago.This is an open access article, available to all readers online, published under a creative commons licensing (https://creativecommons.org/licenses/by/4.0/)
Three new species of the Xylophanes crotonis species-group (Lepidoptera: Sphingidae) from Colombia and a neotype designation for Xylophanes aristor
No full textThree new species of the hawkmoth genus Xylophanes Hübner, 1819 from Colombia are described based on morphological characters and DNA barcodes: Xylophanes camilae Correa-Carmona & Giusti sp. n., Xylophanes pijao Giusti & CorreaCarmona sp. n., and Xylophanes tayrona Correa-Carmona & Giusti sp. n. The new species are compared with the most morphologically similar species within the informal Xylophanes crotonis species-group: Xylophanes aristor (Boisduval, 1870), Xylophanes
crotonis (Walker, 1856) and Xylophanes huloti Haxaire & Vaglia, 2008. Diagnoses, distribution maps, photographs of genital
structures and habitus are provided for each new species. In addition, a dichotomous key is provided to identify the new species
and the most morphologically similar species within the group. To stabilize the nomenclature and fi x the taxon concept, a neotype is designated for Xylophanes aristor.Copyright: © 2021 The Authors. This is an open access article distributed under the terms of the Creative Commons Attribution License, (https://creativecommons.org/licenses/by/2.0/) which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are creditedNHM Repositor
How has the environment shaped geographical patterns of insect body sizes? A test of hypotheses using sphingid moths
Get PDFAim: We mapped the geographical pattern of body sizes in sphingid moths and investigated
latitudinal clines. We tested hypotheses concerning their possible environmental
control, that is, effects of temperature (negative: temperature size rule or
Bergmann's rule; positive: converse Bergmann rule), food availability, robustness to
starvation during extreme weather and seasonality.
Location: Old World and Australia/Pacific region.
Methods: Body size data of 950 sphingid species were compiled and related to their
distribution maps. Focusing on body length, we mapped the median and maximum
size of all species occurring in 100 km grid cells. In a comparative approach, we tested
the predictions from explanatory hypotheses by correlating species' size to the average
environmental conditions encountered throughout their range, under univariate
and multivariate models. We accounted for phylogeny by stepwise inclusion of phylogenetically
informed taxonomic classifications into hierarchical random‐intercept
mixed models.
Results: Median body sizes showed a distinctive geographical pattern, with large species
in the Middle East and the Asian tropics, and smaller species in temperate regions
and the Afrotropics. Absolute latitude explained very little body size variation,
but there was a latitudinal cline of maximum size. Species' median size was correlated
with net primary productivity, supporting the food availability hypothesis, whereas
support for other hypotheses was weak. Environmental correlations contributed
much less (i.e. <10%) to explaining overall size variation than phylogeny (inclusion of
which led to models explaining >70% of variability).
Main conclusion: The intuitive impression of larger species in the tropics is shaped by
larger size maxima. Median body sizes are only very weakly related to latitude. Most
of the geographical variation in body size in sphingid moths is explained by their phylogenetic
past. NPP and forest cover correlate positively with the body size, which
supports the idea that food availability allowed the evolution of larger sizes.The attached document is the author(’s’) final accepted/submitted version of the journal article. You are advised to consult the publisher’s version if you wish to cite from itNHM Repositor