Ichthyostegalia

Ichthyostegalia*
Temporal range: 368–329 Ma
Possibly emerged 395 Ma
Ichthyostega, the nominal genus.
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Superclass: Tetrapoda
Order: †"Ichthyostegalia"
Säve-Söderbergh, 1932
Genera

See text

Ichthyostegalia is an order of extinct amphibians, representing the earliest landliving vertebrates. The group is thus an evolutionary grade rather than a clade.[1] While the group are recognized as having feet rather than fins, most, if not all, had internal gills in adulthood and lived primarily as shallow water fish and spent minimal time on land.

The group evolved from elpistostegalian fish in the late Devonian,[2] or possibly in the middle Devonian.[3][4] They continued to thrive as denizens of swampland and tidal channels throughout the period. They gave rise to the Temnospondyli and then disappeared during the transition to the Carboniferous.[5]

  1. ^ Parsons, Alfred Sherwood Romer, Thomas S. (1986). The vertebrate body (6th ed.). Philadelphia: Saunders College Pub. ISBN 978-0-03-910754-3.{{cite book}}: CS1 maint: multiple names: authors list (link)
  2. ^ "Fossil Record of the Amphibia". ucmp.berkeley.edu. Retrieved 2022-10-03.
  3. ^ Niedźwiedzki (2010). "Tetrapod trackways from the early Middle Devonian period of Poland". Nature. 463 (7277): 43–48. Bibcode:2010Natur.463...43N. doi:10.1038/nature08623. PMID 20054388. S2CID 4428903.
  4. ^ Uppsala University (2010, January 8). Fossil footprints give land vertebrates a much longer history. ScienceDaily. Retrieved January 8, 2010, from https://www.sciencedaily.com/releases/2010/01/100107114420.htm
  5. ^ Anderson, J.S.; Reisz, R.R.; Scott, D.; Fröbisch, N.B.; Sumida, S.S. (2008). "A stem batrachian from the Early Permian of Texas and the origin of frogs and salamanders". Nature. 453 (7194): 515–518. Bibcode:2008Natur.453..515A. doi:10.1038/nature06865. PMID 18497824. S2CID 205212809.