Staurinidia

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Staurinidia
Temporal range: Ediacaran
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Cnidaria
Class: Scyphozoa
Family: Incertae sedis
Genus: Staurinidia
Fedonkin, 1985
Species:
S. crucicula
Binomial name
Staurinidia crucicula
Fedonkin, 1985

Staurinidia is a genus of Ediacaran soft-bodied organism from the deposits of the Ust'-Pinega formation. It is a monotypic genus, containing only the single species Staurinidia crucicula. [1] The genus was first described in 1985 by Russian palaeontologist Mikhail A. Fedonkin. S. crucicula's four-fold symmetry is present as a result of four canals radiating from the middle of a small cavity in the middle of the body. [1] Other forms with four way symmetry, mainly Medusoid forms, from the Ediacaran (Conomedusites, Persimedusites) comprise an essential chunk of the Ediacaran diversity of symmetry; their organisations are similar to, though smaller than, those of a modern-day Scyphozoan Cnidarian. [2]

Contents

Description

S. crucicula fossils are preserved as a small discoidal form baring four radial canals emitting from the fossils centre in which a small cavity is present. The ends of the canals are often swollen when pointing towards the organisms periphery. [1] In very rare instances, tentacles are present and preserved around the outside of the disc's margin. The margins of the disc are very thin with there being no indication of an encircling ridge or canal. [1] Rather deep impressions are preserved of Staurinidia suggesting that the animal would've had significant relief.

The diameter of the body of Staurinidia ranges from 6 millimeters (0.24 in)-10 millimeters (0.39 in), the width of the radial canals is 1 millimeter (0.039 in) and the length of the marginal tentacles being 4 millimeters (0.16 in)-5 millimeters (0.20 in). [1] The canals give the animal a four-fold symmetry typical to that of other Ediacaran Cnidarians. [2] Staurinidia is regarded as one of the simplest of all Ediacaran Cnidarians that show four-way rotational axis. [3]

See also

References

  1. 1 2 3 4 5 Fedonkin, Mikhail A.; Gehling, James G.; Grey, Kathleen; Narbonne, Guy M.; Vickers-Rich, Patricia (Mar 16, 2007). The Rise of Animals: Evolution and Diversification of the Kingdom Animalia. JHU Press. ISBN   9780801886799 . Retrieved July 1, 2022 via Google Books.
  2. 1 2 Origin and Early Evolution of the Metazoa. Springer. 21 November 2013. ISBN   9781489924278.
  3. The Vendian System: Vol. 1 Paleontology. Springer. 27 August 1990. ISBN   9783540501428.