Research Highlights: Massive New Species from Cambrian Period Discovered in Canada

Research Highlights: Massive New Species from Cambrian Period Discovered in Canada

  • Radiodonts are arthropods that existed worldwide during the Cambrian period.[2]
  • Radiodonts are known by their distinctive frontal appendages which are structurally diverse and used for many functions.[2]
  • Radiodonts were among the largest and most diversified lower palaeozoic predators.
  • Lower Palaeozoic includes three geological systems: the Cambrian (541.0 to 485.4 million years ago), the Ordovician (485.4 to 443.4 million years ago) and the Silurian (443.4 – 419.2 million years ago).[3]
  • These animals were widely distributed around the world occupying different ecological niches including benthic foragers, nektonic suspension feeders, and apex predators.
  • Benthic foragers search for relatively sessile prey usually at the lowest level of a body of water, while suspension feeders feed on particles of organic matter suspended in the water.[4][5]
  • Researchers discovered the largest Cambrian hurdiid radiodont known so far.
  • Hurdiidae are known to have frontal appendages with distal region composed of 5 subequal blade-like endites, alongside the enlarged head carapaces and tetraradial mouthpart.[6]
  • Endite is one of the appendages of the inner side of the limb of an arthropod.[7]
  • Researchers named the newly discovered species as Titanokorys gainesi, gen. et sp. nov.
  • The new species was discovered at Burgess Shale.
  • Burgess Shale is a fossil-bearing deposit exposed in the Canadian Rockies of British Columbia in Canada and it is popular for the exceptional preservation of the soft parts of its fossils.[8]
  • Researchers speculated that the new species can reach half a meter in length.
  • The new species has a very large egg-shaped central carapace with distinct short posterolateral projections and a frontal spine.
  • Analyses emphasize the high diversity of carapace structures in hurdiids.
  • Results suggest that Titanokorys bridges a morphological gap between forms with short and long carapaces.
  • However, carapace shape is prone to homoplasy and shows no consistent relationship with trophic ecology.
  • Homoplasy is the similarity in form or function between parts of different species that are not attributable to their common ancestor but is the result of parallel or convergent evolution.[9]
  • Trophic ecology is the study of the structure of feeding relationships among organisms in an ecosystem.[10]
  • Titanokorys shares similar rake-like appendages for sediment-sifting with Cambroraster.
  • Cambroraster is characterized by a significantly enlarged horseshoe-shaped dorsal carapace.[11]
  • The occurrence of Titanokorys and Cambroraster on the same bedding planes emphasizes potential competition for benthic resources and the high diversity of large predators supported by Cambrian communities.

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Caron J.-B. and Moysiuk J. 2021. A giant nektobenthic radiodont from the Burgess Shale and the significance of hurdiid carapace diversity. R. Soc. open sci.8210664210664.