Hyoliths are Palaeozoic lophophorates

  title={Hyoliths are Palaeozoic lophophorates},
  author={Joseph Moysiuk and Martin R. Smith and Jean‐Bernard Caron},
Hyoliths are abundant and globally distributed ‘shelly’ fossils that appear early in the Cambrian period and can be found throughout the 280 million year span of Palaeozoic strata. [] Key Method Here we examine over 1,500 specimens of the mid-Cambrian hyolith Haplophrentis from the Burgess Shale and Spence Shale Lagerstätten. We reconstruct Haplophrentis as a semi-sessile, epibenthic suspension feeder that could use its helens to elevate its tubular body above the sea floor. Exceptionally preserved soft…
Are hyoliths Palaeozoic lophophorates?
The first soft parts associated with the feeding apparatus of an orthothecid hyolith, Triplicatella opimus from the Chengjiang biota of South China, are described, suggesting that hyoliths are more likely to be basal members of the lophotrochozoans rather than lophophorates closely linked with the Phylum Brachiopoda.
Hyoliths with pedicles illuminate the origin of the brachiopod body plan
A new orthothecide hyolith from the Chengjiang Lagerstätte (Cambrian Series 2 Stage 3) is described, which exhibits a non-mineralized attachment structure that strikingly resembles the brachiopod pedicle—the first report of a peduncular organ in hyoliths.
Exceptionally preserved hyolithids from the middle Cambrian of North China
Abstract Hyoliths are extinct enigmatic organisms of early lophotrochozoan affinity known globally from the Palaeozoic Era and were especially diverse and abundant in the Cambrian Period. However,
A middle Cambrian arthropod with chelicerae and proto-book gills
Fossil material from the middle Cambrian Burgess Shale is used to show that Mollisonia plenovenatrix possessed robust but short chelicerae that were placed very anteriorly, between the eyes, which suggests that chelicers evolved a specialized feeding function early on, possibly as a modification of short antennules.
Homologous shell microstructures in Cambrian hyoliths and molluscs
Hyoliths were among the earliest biomineralizing metazoans in Palaeozoic marine environments. They have been known for two centuries and widely assigned to lophotrochozoans. However, their origin and
Pelagiella exigua, an early Cambrian stem gastropod with chaetae: lophotrochozoan heritage and conchiferan novelty
The orientation of Pelagiella and the asymmetry of its gills, comparable to features of several living vetigastropods, nominate it as the earliest fossil mollusc known to exhibit evidence of the developmental torsion characteristic of gastropods.
Palaeoecology of Voulteryon parvulus (Eucrustacea, Polychelida) from the Middle Jurassic of La Voulte-sur-Rhône Fossil-Lagerstätte (France)
Exceptionally preserved specimens of the polychelidan lobster Voulteryon parvulus, from the Jurassic of La Voulte-sur-Rhône Fossil-Lagerstätte, France, bearing eyes with hexagonal and square facets, ovaries, and a unique association with epibiont thecideoid brachiopods are presented, giving insights onto the palaeoenvironment of this Lagerstâtte.
Palaeobiology of orthothecide hyoliths from the Cambrian Manto Formation of Hebei Province, North China
Newly discovered specimens of the orthothecide hyoliths in Hebei Province of North China reveal new data on diversity, skeletal microstructure and palaeoecology of the order Orthothecida. Decoritheca
Finding a home for hyoliths
Hyoliths have recently been identified as brachiopods based on the description of an attachment stalk and a tentaculate feeding apparatus, but an alternative view is presented, interpreting the putative pedicle as a damaged shell apex and questioning whether the feeding apparatus ought to be termed a lophophore.


Biology of the Hyolitha
Although the shell form and skeletal ultra-structure of hyoliths are of a molluscan type, the muscle insertions suggest that the hyolith cone is not homologous with the dorsal exoskeleton of primitive mollsuscs.
A Complete Reconstruction of the Hyolithid Skeleton
Abstract Hyolithids are a group of Paleozoic lophotrochozoans with a four-pieced skeleton consisting of a conch, an operculum, and a pair of lateral ‘spines' named helens. Both the conch and
Hyolitha: status of the phylum
Reconstructions of the anatomy of hyoliths indicate that it is unlikely that both groups shared a common molluscan ancestor, therefore,hyoliths are probably not mollUScs.
Comparative study of the muscle insertion pattern indicates that hyolithid did not have serially arranged muscles and that all hyolithids may have had a common skeleto-muscular system.
On 20 years of Lophotrochozoa
  • K. Kocot
  • Biology
    Organisms Diversity & Evolution
  • 2015
Resolving lophotrochozoan phylogeny will provide important insight into how these complex and diverse body plans evolved and provide a much-needed framework for comparative studies.
The scleritome of Eccentrotheca from the Lower Cambrian of South Australia: Lophophorate affinities and implications for tommotiid phylogeny
The first partially articulated scleritome of a tommotiid, Eccentrotheca sp., is described from the Lower Cambrian of South Australia. The Eccentrotheca scleritome consists of individual sclerites;
Aspects of the biology of Hyolitha (Mollusca)
The Hyolithida were probably deposit feeders living in shallow water, and accordingly were tentaculate, and except for the more complex musculature associated with an elaborate operculum, Orthothecida are judged to have had a similar anatomy.