Eldoniid

Eldonioidea
Temporal range: Cambrian–Devonian
Fossils of Eldonia berbera, from the Late Ordovician of Morocco
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Clade: †Cambroernida
Class: †Eldonioidea
Dzik, 1991
Families

Eldoniids or eldonioids are an extinct clade of enigmatic disc-shaped animals which lived in the early to middle Paleozoic (Cambrian to Devonian). They are characterized by their "medusoid" (jellyfish-shaped) bodies, with the form of a shallow dome opening below to an offset mouth supplemented by filamentous tentacles.[1] Internally, they have a distinctive C-shaped cavity encompassing the gut, as well as hollow radial (radiating) structures arranged around a central ring canal. Most eldoniids are soft-bodied and can only be preserved in lagerstätten, but a few species may have hosted mineralized deposits.[2][3] Historically, the affinities of eldoniids was enigmatic; recently, they been assessed as cambroernid deuterostomes.[4][5] Their lifestyle is still an unresolved question; some authors reconstruct eldoniids as free-floating planktonic predators similar to jellyfish,[1] while others argue that they were passive detritivores, embedded within the seabed for much of their life.[3]

  1. ^ a b Cite error: The named reference :3 was invoked but never defined (see the help page).
  2. ^ Chen, Jun-yuan; Zhu, Mao-yan; Zhou, Gui-qing (1995). "The Early Cambrian medusiform metazoan Eldonia from the Chenjiang Lagerstätte" (PDF). Acta Palaeontologica Polonica. 40 (3): 213–244.
  3. ^ a b Cite error: The named reference :2 was invoked but never defined (see the help page).
  4. ^ Cite error: The named reference Caron2010 was invoked but never defined (see the help page).
  5. ^ Cite error: The named reference li2023 was invoked but never defined (see the help page).