ORCID Profile
0000-0001-5369-5879
Current Organisation
University of Lausanne
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Publisher: American Association for the Advancement of Science (AAAS)
Date: 20-03-2009
Abstract: As the largest predators of the Cambrian seas, the anomalocaridids had an important impact in structuring the first complex marine animal communities, but many aspects of anomalocaridid morphology, ersity, ecology, and affinity remain unclear owing to a paucity of specimens. Here we describe the anomalocaridid Hurdia , based on several hundred specimens from the Burgess Shale in Canada. Hurdia possesses a general body architecture similar to those of Anomalocaris and Laggania , including the presence of exceptionally well-preserved gills, but differs from those anomalocaridids by possessing a prominent anterior carapace structure. These features lify and clarify the ersity of known anomalocaridid morphology and provide insight into the origins of important arthropod features, such as the head shield and respiratory exites.
Publisher: The Royal Society
Date: 09-02-2022
Abstract: Once considered ‘weird wonders’ of the Cambrian, the emblematic Burgess Shale animals Anomalocaris and Opabinia are now recognized as lower stem-group euarthropods and have provided crucial data for constraining the polarity of key morphological characters in the group. Anomalocaris and its relatives (radiodonts) had worldwide distribution and survived until at least the Devonian. However, despite intense study, Opabinia remains the only formally described opabiniid to date. Here we reinterpret a fossil from the Wheeler Formation of Utah as a new opabiniid, Utaurora comosa nov. gen. et sp. By visualizing the s le of phylogenetic topologies in treespace, our results fortify support for the position of U. comosa beyond the nodal support traditionally applied. Our phylogenetic evidence expands opabiniids to multiple Cambrian stages. Our results underscore the power of treespace visualization for resolving imperfectly preserved fossils and expanding the known ersity and spatio-temporal ranges within the euarthropod lower stem group.
Publisher: Scandinavian University Press / Universitetsforlaget AS
Date: 10-2018
DOI: 10.1111/LET.12266
Publisher: Wiley
Date: 04-03-2013
DOI: 10.1111/PALA.12029
Publisher: Elsevier BV
Date: 09-2016
Publisher: PeerJ
Date: 19-01-2021
DOI: 10.7717/PEERJ.10509
Abstract: Radiodonts have long been known from Cambrian deposits preserving non-biomineralizing organisms. In Utah, the presence of these panarthropods in the Spence and Wheeler (House Range and Drum Mountains) biotas is now well-documented. Conversely, radiodont occurrences in the Marjum Formation have remained scarce. Despite the large amount of work undertaken on its erse fauna, only one radiodont ( Peytoia ) has been reported from the Marjum Biota. In this contribution we quadruple the known radiodont ersity of the Marjum fauna, with the description of the youngest members of two genera, Caryosyntrips and Pahvantia , and that of a new taxon Buccaspinea cooperi gen. et sp. nov. This new taxon can be identified from its large oral cone bearing robust hooked teeth with one, two, or three cusps, and by the unique endite morphology and organisation of its frontal appendages. Appendages of at least 12 podomeres bear six recurved plate-like endites proximal to up to four spiniform distal endites. Pahvantia hastata specimens from the Marjum Formation are particularly large, but otherwise morphologically indistinguishable from the carapace elements of this species found in the Wheeler Formation. One of the two new Caryosyntrips specimens can be confidently assigned to C. camurus . The other bears the largest spines relative to appendage length recorded for this genus, and possesses endites of variable size and unequal spacing, making its taxonomic assignment uncertain. Caryosyntrips, Pahvantia , and Peytoia are all known from the underlying Wheeler Formation, whereas isolated appendages from the Spence Shale and the Wheeler Formation, previously assigned to Hurdia , are tentatively reidentified as Buccaspinea . Notably, none of these four genera occurs in the overlying Weeks Formation, providing supporting evidence of a faunal restructuring around the Drumian-Guzhangian boundary. The description of three additional nektonic taxa from the Marjum Formation further documents the higher relative proportion of free-swimming species in this biota compared to those of the Wheeler and Weeks Lagerstätten. This could be related to a moderate deepening of the basin and/or changing regional ocean circulation at this time.
Publisher: Cambridge University Press (CUP)
Date: 2014
DOI: 10.1666/13-067
Abstract: Recent description of the oral cone of Anomalocaris canadensis from the Burgess Shale (Cambrian Series 3, Stage 5) highlighted significant differences from published accounts of this iconic species, and prompts a new evaluation of its morphology as a whole. All known specimens of A. canadensis , including previously unpublished material, were examined with the aim of providing a cohesive morphological description of this stem lineage arthropod. In contrast to previous descriptions, the dorsal surface of the head is shown to be covered by a small, oval carapace in close association with paired stalked eyes, and the ventral surface bears only the triradial oral cone, with no evidence of a hypostome or an anterior sclerite. The frontal appendages reveal new details of the arthrodial membranes and a narrower cross-section in dorsal view than previously reconstructed. The posterior body region reveals a complex suite of digestive, respiratory, and locomotory characters that include a differentiated foregut and hindgut, a midgut with paired glands, gill-like setal blades, and evidence of muscle bundles and struts that presumably supported the swimming movement of the body flaps. The tail fan includes a central blade in addition to the previously described three pairs of lateral blades. Some of these structures have not been identified in other anomalocaridids, making Anomalocaris critical for understanding the functional morphology of the group as a whole and corroborating its arthropod affinities.
Publisher: Cold Spring Harbor Laboratory
Date: 11-03-2021
DOI: 10.1101/2021.03.10.434726
Abstract: Once considered ‘weird wonders’ of the Cambrian, the emblematic Burgess Shale animals Anomalocaris and Opabinia are now recognized as lower stem-group euarthropods. Anomalocaris and its relatives (radiodonts) had a worldwide distribution and survived until at least the Devonian, whereas - despite intense study - Opabinia remains the only formally described opabiniid to date. Here we reinterpret a fossil from the Wheeler Formation of Utah as a new opabiniid, KUMIP 314087. By visualizing the s le of phylogenetic topologies in treespace, our results fortify support for the position of KUMIP 314087 beyond the nodal support traditionally applied. Our phylogenetic evidence expands opabiniids to multiple Cambrian Stages spanning approximately five million years. Our results underscore the power of treespace visualization for resolving imperfectly preserved fossils and expanding the known ersity and spatiotemporal ranges within the euarthropod lower stem group. This work contains a new biological name. New names in preprints are not considered available by the ICZN. To avoid ambiguity, the new biological name is not included in this preprint, and the specimen number (KUMIP 314087) is used as a placeholder. Cover image. Artistic reconstruction of the new opabiniid from the Wheeler Formation, Utah, USA (Cambrian: Drumian). Artwork by F. Anthony.
Publisher: Wiley
Date: 13-08-2222
DOI: 10.1002/SPP2.1231
Publisher: Cambridge University Press (CUP)
Date: 07-2016
DOI: 10.1017/JPA.2016.67
Abstract: The recently described radiodontan Lyrarapax unguispinus Cong et al., 2014 from the Chengjiang biota (Cambrian Series 2, Stage 3) highlighted a new morphological type of frontal appendage and unique mouth structures, a functional combination reinforcing the ersification of feeding strategies of radiodontans during the early Cambrian. Here we describe Lyrarapax trilobus n. sp. from the same fossil Konservat-Lagerstätte. The new species differs from L . unguispinus in the morphology and distribution of endites on the frontal appendage and the strengthening structure of the body flaps. The two species resemble each other in body shape (pattern of flap size), neck segment number, cephalic plates, and most importantly a mouth characterized by concentric wrinkled furrows. The latter confirms that a soft mouth without sclerotized plates is a real feature of Lyrarapax and supports the idea that oral structures provide valid diagnostic characters within Radiodonta.
Publisher: The Royal Society
Date: 05-07-2023
Abstract: The stem-group euarthropod Anomalocaris canadensis is one of the largest Cambrian animals and is often considered the quintessential apex predator of its time. This radiodont is commonly interpreted as a demersal hunter, responsible for inflicting injuries seen in benthic trilobites. However, controversy surrounds the ability of A. canadensis to use its spinose frontal appendages to masticate or even manipulate biomineralized prey. Here, we apply a new integrative computational approach, combining three-dimensional digital modelling, kinematics, finite-element analysis (FEA) and computational fluid dynamics (CFD) to rigorously analyse an A. canadensis feeding appendage and test its morphofunctional limits. These models corroborate a raptorial function, but expose inconsistencies with a capacity for durophagy. In particular, FEA results show that certain parts of the appendage would have experienced high degrees of plastic deformation, especially at the endites, the points of impact with prey. The CFD results demonstrate that outstretched appendages produced low drag and hence represented the optimal orientation for speed, permitting acceleration bursts to capture prey. These data, when combined with evidence regarding the functional morphology of its oral cone, eyes, body flaps and tail fan, suggest that A. canadensis was an agile nektonic predator that fed on soft-bodied animals swimming in a well-lit water column above the benthos. The lifestyle of A. canadensis and that of other radiodonts, including plausible durophages, suggests that niche partitioning across this clade influenced the dynamics of Cambrian food webs, impacting on a erse array of organisms at different sizes, tiers and trophic levels.
Publisher: Springer Science and Business Media LLC
Date: 02-05-2014
DOI: 10.1038/NCOMMS4641
Abstract: Understanding the way in which animals ersified and radiated during their early evolutionary history remains one of the most captivating of scientific challenges. Integral to this is the 'Cambrian explosion', which records the rapid emergence of most animal phyla, and for which the triggering and accelerating factors, whether environmental or biological, are still unclear. Here we describe exceptionally well-preserved complex digestive organs in early arthropods from the early Cambrian of China and Greenland with functional similarities to certain modern crustaceans and trace these structures through the early evolutionary lineage of fossil arthropods. These digestive structures are assumed to have allowed for more efficient digestion and metabolism, promoting carnivory and macrophagy in early arthropods via predation or scavenging. This key innovation may have been of critical importance in the radiation and ecological success of Arthropoda, which has been the most erse and abundant invertebrate phylum since the Cambrian.
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Allison Daley.