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Arthropod fossil data increase congruence of morphological and molecular phylogenies.
Enhanced congruence is shown between molecular and morphological phylogenies based on 753 morphological characters for 309 fossil and Recent panarthropods, which resolve hexapods within Crustacea, with remipedes as their closest extant relatives, and show that the traditionally close relationship between myriapods and hexapod is an artefact of convergent character acquisition during terrestrialisation.
FOSSIL CALIBRATIONS FOR THE ARTHROPOD TREE OF LIFE
A series of rigorously vetted calibration fossils for arthropod evolutionary history, taking into account recently published guidelines for best practice in fossil calibration are presented, resulting in 80 fossil calibrations for 102 clades.
Cambrian bivalved arthropod reveals origin of arthrodization
- David A. Legg, M. Sutton, G. Edgecombe, Jean‐Bernard Caron
- Environmental Science, GeographyProceedings of the Royal Society B: Biological…
- 7 December 2012
A cladistic analysis resolved a new arthropod from the Tulip Beds locality of the Burgess Shale Formation as the basal-most member of a paraphyletic grade of nekto-benthic forms with bivalved carapaces and suggests that arthrodization (sclerotization and jointing of the exoskeleton) evolved to facilitate swimming.
Silurian horseshoe crab illuminates the evolution of arthropod limbs
- D. Briggs, D. Siveter, D. Siveter, M. Sutton, R. Garwood, David A. Legg
- Biology, Environmental ScienceProceedings of the National Academy of Sciences
- 11 September 2012
Both branches of the prosomal limbs of this new fossil are robust and segmented in contrast to their morphology in Cambrian arthropods, revealing that a true biramous limb was once present in chelicerates as well as in the mandibulates.
Pancrustacean Evolution Illuminated by Taxon-Rich Genomic-Scale Data Sets with an Expanded Remipede Sampling
- J. Lozano-Fernandez, M. Giacomelli, J. Olesen
- Biology, Environmental ScienceGenome Biology and Evolution
- 4 July 2019
Mapping key crustacean tagmosis patterns and developmental characters across the revised phylogeny suggests that the ancestral pancrustacean was relatively short-bodied, with extreme body elongation and anamorphic development emerging later in pancrustACEan evolution.
The phylogeny of aglaspidid arthropods and the internal relationships within Artiopoda
The phylogenetic position of aglaspidid arthropod groups makes them good outgroup candidates for analysing the internal relationships within the groups that form Trilobitomorpha, and the new clade “Vicissicaudata” is proposed to encompass these arthropods, which are characterized by a differentiated posterior region.
Sanctacaris uncata: the oldest chelicerate (Arthropoda)
- David A. Legg
- BiologyDie Naturwissenschaften
- 9 October 2014
Topology indicates that many purported chelicerate features, such as lamellar gills, and a differentiated posterior abdomen evolved sequentially in the chelicerates stem-lineage.
Origins and early evolution of arthropods
With respect to the interrelationships of the three extant clades of Panarthropoda, a sister group relationship between Onychophora and Arthropoda is endorsed by transcriptomics and microRNAs, although this hypothesis forces homoplasy in characters of the segmental ganglia that are shared by tardigrades and arthropods.
The Arthropod Fossil Record
With respect to animal life, we inhabit a planet dominated by arthropods. The Recent is not geologically anomalous in this respect—arthropods have been megadiverse for some 520 million years, since…
The affinities of the cosmopolitan arthropod Isoxys and its implications for the origin of arthropods
The results indicate that Isoxys was indeed a monophyletic genus with all representatives united by the presence of an expansive dorsal shield with prominent antero- and posterolateral cardinal spines, and indicates that I soxys occupies a crucial role in arthropod evolution, resolving at the base of Arthropoda.