...–508 Ma), with possible trace fossils in the latest Ediacaran (<556 Ma). The fossil record of Ecdysozoa is among the best understood of major animal clades and is believed to document their origins and evolutionary history well. Strikingly, however, molecular clock analyses have implied...

... a ); or close to the root of Superphylum Ecdysozoa ( Budd 2001 ). Precise anatomical observations of additional fossil material, such as the valuable description of new cricocosmiid specimens by Shi et al. (2021 a ) , are needed in order to resolve this uncertainty. Tabelliscolex and its close...

... phylogenetic analyses. The affinity of cricocosmiids within Ecdysozoa is therefore of much interest, as is testing the homology of these seriated structures. We report four new specimens of the rare cricocosmiid Tabelliscolex hexagonus , yielding new details of the ventral trunk projections, sclerites...

...Jie Yang; Martin R Smith; Xi-guang Zhang; Xiao-yu Yang Abstract Palaeoscolecid worms are widespread in the Palaeozoic period, and are of key importance to understanding the emergence of moulting animals (superphylum Ecdysozoa). However, palaeoscolecids lack a diagnostic set of morphological...

... morphology required for an A. alleghaniensis tracemaker. Precise systematic affinities of this new arthropod could not be determined. This discovery supports the conclusion that the tracemakers of various Arthrophycus ichnospecies are likely poorly preserved, and presently unknown, members of the Ecdysozoa...

... ichnospecies Arthrophycus parallelus is neither an annelid nor a previously described arthropod but a yet unknown member of the Ecdysozoa. There are to date no fossil traces attributed specifically to centipedes. Trackways attributed to undifferentiated myriapods (e.g., Buatois et al., 1998 ) are more...

... protostomians to achieve biomineralization during the Terreneuvian Epoch, mainly the Fortunian Age. Fast evolutionary radiation within the Lophotrochozoa was followed by radiation of the sclerotized and biomineralized Ecdysozoa during Stage 3. The first mineralized skeletons of the Deuterostomia, represented...

... Press must be obtained prior to any commercial use. eodiscid trilobites Somersault configuration exuviae Cambrian Stage 3 South China Ecdysis refers to the process by which the exoskeleton is shed during growth in the clade Ecdysozoa which includes arthropods, nematodes and several...

...Figure 5. Phylogeny of Ecdysozoa, based on Sørensen et al. (2008) and Conway Morris and Peel (in press) , showing inferred placement of Sirilorica in the total-group of Loricifera and Sicyophorus in the total-group of Priapulida. Shergoldiana is placed within the total-group...

... the bilaterian clades Ecdysozoa, Lophotrochozoa, and Deuterostomia. Figure 1. Composite phylogeny of the Metazoa. More inclusive clades discussed in the text are delimited by boxes or node designations. The basic topology is from the 18s rDNA and morphological analysis of Zrzavy et al. (1998...

... in the Cambrian was first evaluated); (g) A distinction between the optic spots of annelids and the eyes of arthropods – another archaic criterion given that, today, annelids are not included within Ecdysozoa (Giribet & Edgecombe, 2017 ); (h) All muscles consisting of ‘striped (i.e. striated) muscular...

... the phylogenetic position of nematodes. This is a contentious issue because nematodes are placed within the Ecdysozoa on the basis of ribosomal sequence analysis ( Aguinaldo et al. 1997 ; Peterson and Eernisse 2001 ; Mallatt and Winchell 2002 ; Mallatt et al. 2004 ), the possession of ecdysozoan-specific...

.... Recent study indicates that priapulids belong to Cycloneuralia of Ecdysozoa, and they have a close relationship with kinorhynchans and loriciferans (Nielsen, 2012 ). In past decades, well-preserved fossil priapulids have been frequently recovered from Konservat-Lagerstätten, particularly in Cambrian...

... considerably since 1989, largely through molecular data. The cladogram ( Fig. 2 ) looked very different prior to the recognition of the Lophotrochozoa and Ecdysozoa. Regardless of phylogenetic hypotheses, however, new fossil discoveries have extended or provided more convincing evidence for the stratigraphic...

... . Grayson JF. 1956 . The conversion of calcite to fluorite . Micropaleontology . 2 ( 1 ): 71 – 78 . Greven H , Kaya M , Baran T. 2016 . The presence of α-chitin in Tardigrada with comments on chitin in the Ecdysozoa . Zoologischer Anzeiger - A Journal of Comparative Zoology...

... ). Palaeoscolecids are mainly considered to represent members of Ecdysozoa. Their position within this clade is still under discussion, but cladistic analyses indicate that they are either close relatives of nematomorphs ( Hou and Bergström, 1994 ) or part of an extinct sister clade to the priapulids ( Wills, 1998...