1366 research outputs found
Sort by
Attenuated evolution of mammals through the Cenozoic
Get PDFThe Cenozoic diversification of placental mammals is the archetypal adaptive radiation. Yet, discrepancies between molecular divergence estimates and the fossil record fuel ongoing debate around the timing, tempo, and drivers of this radiation. Analysis of a three-dimensional skull dataset for living and extinct placental mammals demonstrates that evolutionary rates peak early and attenuate quickly. This long-term decline in tempo is punctuated by bursts of innovation that decreased in amplitude over the past 66 million years. Social, precocial, aquatic, and herbivorous species evolve fastest, especially whales, elephants, sirenians, and extinct ungulates. Slow rates in rodents and bats indicate dissociation of taxonomic and morphological diversification. Frustratingly, highly similar ancestral shape estimates for placental mammal superorders suggest that their earliest representatives may continue to elude unequivocal identification.Copyright © 2022, The Authors. 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
How woodcocks produce the most brilliant white plumage patches among the birds
Get PDFUntil recently, and when compared with diurnal birds that use contrasting plumage patches and complex feather structures to convey visual information, communication in nocturnal and crepuscular species was considered to follow acoustic and chemical channels. However, many birds that are active in low-light environments have evolved intensely white plumage patches within otherwise inconspicuous plumages. We used spectrophotometry, electron microscopy, and optical modelling to explain the mechanisms producing bright white tail feather tips of the Eurasian woodcock Scolopax rusticola. Their diffuse reflectance was approximately 30% higher than any previously measured feather. This intense reflectance is the result of incoherent light scattering from a disordered nanostructure composed of keratin and air within the barb rami. In addition, the flattening, thickening and arrangement of those barbs create a Venetian-blind-like macrostructure that enhances the surface area for light reflection. We suggest that the woodcocks have evolved these bright white feather patches for long-range visual communication in dimly lit environments.Copyright © 2023 TheAuthors. Published by the Royal Society under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/4.0/, which permits unrestricted use, provided the original author and source are credited. The attached file is the published version of the article.NHM Repositor
Description of the early stages of Compsulyx cochereaui (Viette, 1971) and a discussion of its systematic position (Lepidoptera, Sphingidae, Smerinthinae, Ambulycini)
No full textThe authors describe the early stages, totally unknown of the species of Sphingidae emblematic of New Caledonia. They discuss possible host plants of the species, which all belong to the family Cunoniaceae. Without questioning the validity of the Ambulycini tribe, they question its characterization on the criterion of the pupa put forward by Nakamura (1977). All larval stages, from egg to chrysalis, are illustrated.The attached file is the submitted version of the article. You are advised to consult the published version if you wish to cite from it.NHM Repositor
The colourful journey of the Eurasian Collared Dove Streptopelia decaocto
Get PDFIn the 18th and 19th centuries the Eurasian Collared Dove Streptopelia decaocto was widely considered to be the wild ancestor of the domesticated Barbary Dove (domestic S. risoria), and even following its recognition as a species its taxonomic status was a source of confusion. Since 1900, and the species’ massive geographic expansion (both naturally and by introduction) the two taxa have occasionally met. The resultant hybridisation is probably the cause of the large number of Eurasian Collared Doves with the aberrant pale colour of Barbary Doves in areas where hybridisation has occurred.Copyright:© 2022 The Authors; This is an open‐access article distributed under the terms of the
Creative Commons Attribution-NonCommercial Licence, which permits unrestricted use. The attached file is the published version of the article.NHM Repositor
Notes on a recently described subspecies, and the poorly known nominate subspecies of Rüppell's Parrot, Poicephalus rueppellii mariettae and P. r. rueppellii
Get PDFRüppell’s Parrot Poicephalus rueppellii was until recently considered to be a monotypic species. Birds from parts of north-western and west-central Angola, however, differ significantly in colour and size from the better-known populations
across the rest of their range, which fact was overlooked until very recently. Because the name rueppellii was originally applied to the less-known Angolan population, it was the commoner southern population that lacked a taxonomic identity. The latter
was described as Poicephalus rueppellii mariettae Hubers & Schnitker, 2022.Copyright: © 2023 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. The attached file is the published version of the article.NHM Repositor
The taxonomic history of Black-shouldered Peafowl; with Darwin's help downgraded from species to variation
Get PDFIn the 19th century the black-shouldered variety of Indian Peafowl Pavo cristatus was erroneously viewed by many as a separate species, named P. nigripennis. Others had doubts about its taxonomic status, but Darwin presented firm evidence for it being a variety under domestication, which treatment is now well established and accepted. It being a colour variation rather than a wild species was important for Darwin to prove, as otherwise it could undermine his theory of slow modification by natural selection in the wild.Copyright: © 2023 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. The attached file is the published version of the article.NHM Repositor
Attenuated evolution of mammals through the Cenozoic
Get PDFThe Cenozoic diversification of placental mammals is the archetypal adaptive radiation. Yet, discrepancies between molecular divergence estimates and the fossil record fuel ongoing debate around the timing, tempo, and drivers of this radiation. Analysis of a three-dimensional skull dataset for living and extinct placental mammals demonstrates that evolutionary rates peak early and attenuate quickly. This long-term decline in tempo is punctuated by bursts of innovation that decreased in amplitude over the past 66 million years. Social, precocial, aquatic, and herbivorous species evolve fastest, especially whales, elephants, sirenians, and extinct ungulates. Slow rates in rodents and bats indicate dissociation of taxonomic and morphological diversification. Frustratingly, highly similar ancestral shape estimates for placental mammal superorders suggest that their earliest representatives may continue to elude unequivocal identification.Copyright © 2022, The Authors. 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
Microbial-Based Products to Control Soil-Borne Pathogens: Methods to Improve Efficacy and to Assess Impacts on Microbiome
No full textMicrobial-based products (either as biopesticide or biofertilizers) have a long history of application, though their use is still limited, mainly due to a perceived low and inconsistent efficacy under field conditions. However, their efficacy has always been compared to chemical products, which have a completely different mechanism of action and production process, following the chemical paradigm of agricultural production. This paradigm has also been applied to regulatory processes, particularly for biopesticides, making the marketing of microbial-based formulations difficult. Increased knowledge about bioinocula behavior after application to the soil and their impact on soil microbiome should foster better exploitation of microbial-based products in a complex environment such as the soil. Moreover, the multifunctional capacity of microbial strains with regard to plant growth promotion and protection should also be considered in this respect. Therefore, the methods utilized for these studies are key to improving the knowledge and understanding of microbial-based product activity and improving their efficacy, which, from farmers’ point of view, is the parameter to assess the usefulness of a treatment. In this review, we are thus addressing aspects related to the production and formulation process, highlighting the methods that can be used to evaluate the functioning and impact of microbial-based products on soil microbiome, as tools supporting their use and marketing.Copyright: © 2023 by the authors.
Licensee MDPI, Basel, Switzerland.
This article is an open access article
distributed under the terms and
conditions of the Creative Commons
Attribution (CC BY) license (https://
creativecommons.org/licenses/by/
4.0/).
The NHM-affiliated author Flavia Pinzari was funded by the H2020-MSCA-IF-EF-SE project “AlienInSoil”. This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 892048”NHM RepositoryNHM Repositor
Cambrian stem-group ambulacrarians and the nature of the ancestral deuterostome
No full textDeuterostomes are characterized by some of the most widely divergent body plans in the animal kingdom. These striking morphological differences have hindered efforts to predict ancestral characters, with the origin and earliest evolution of the group remaining ambiguous. Several iconic Cambrian fossils have been suggested to be early deuterostomes and hence could help elucidate ancestral character states. However, their phylogenetic relationships are controversial. Here, we describe new, exceptionally preserved specimens of the discoidal metazoan Rotadiscus grandis from the early Cambrian Chengjiang biota of China. These reveal a previously unknown double spiral structure, which we interpret as a chordate-like covering to a coelomopore, located adjacent to a horseshoe-shaped tentacle complex. The tentacles differ in key aspects from those seen in lophophorates and are instead more similar to the tentacular systems of extant pterobranchs and echinoderms. Thus, Rotadiscus exhibits a chimeric combination of ambulacrarian and chordate characters. Phylogenetic analyses recover Rotadiscus and closely related fossil taxa as stem ambulacrarians, filling a significant morphological gap in the deuterostome tree of life. These results allow us to reconstruct the ancestral body plans of major clades of deuterostomes, revealing that key traits of extant forms, such as a post-analregion, gillbars, and a U-shaped gut, evolved through convergence.Copyright © 2023 The Author(s). Published by Elsevier Inc. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).NHM RepositoryNHM Repositor
Reconstructing the feeding ecology of Cambrian sponge reefs: the case for active suspension feeding in Archaeocyatha
No full textSponge-grade Archaeocyatha were early Cambrian biomineralizing metazoans that constructed reefs globally. Despite decades of research, many facets of archaeocyath palaeobiology remain unclear, making it difficult to reconstruct the palaeoecology of Cambrian reef ecosystems. Of specific interest is how these organisms fed; previous experimental studies have suggested that archaeocyaths functioned as passive suspension feeders relying on ambient currents to transport nutrient-rich water into their central cavities. Here, we test this hypothesis using computational fluid dynamics (CFD) simulations of digital models of select archaeocyath species. Our results demonstrate that, given a range of plausible current velocities, there was very little fluid circulation through the skeleton, suggesting obligate passive suspension feeding was unlikely. Comparing our simulation data with exhalent velocities collected from extant sponges, we infer an active suspension feeding lifestyle for archaeocyaths. The combination of active suspension feeding and biomineralization in Archaeocyatha may have facilitated the creation of modern metazoan reef ecosystems. The attached file is the published version of the article.Copyright © 2023 The Authors. Published by the Royal Society under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/4.0/, which permits unrestricted use, provided the original author and source are credited.NHM Repositor