Chroniosaurus

{{Short description|Extinct genus of tetrapodomorphs}}

{{Automatic taxobox

| fossil_range = {{fossil_range|255}} Upper Permian

| image = Chroniosaurus dongusDB12.jpg

| image_caption = C. dongusensis

| display_parents = 3

| taxon = Chroniosaurus

| authority = Tverdochlebova, 1972

| subdivision_ranks = Species

| subdivision =

• †C. dongusensis Tverdokhlebova, 1972 (type)
• †C. levis Golubev, 1998

}}

File:Chroniosaurus dong12DB.jpg

Chroniosaurus is an extinct genus of chroniosuchid stegocephalian, often considered a reptiliomorph{{cite journal |last1=Buchwitz |first1=Michael |last2=Foth |first2=Christian |last3=Kogan |first3=Ilja |last4=Voigt |first4=Sebastian |title=On the use of osteoderm features in a phylogenetic approach on the internal relationships of the Chroniosuchia (Tetrapoda: Reptiliomorpha) |journal=Palaeontology |date=May 2012 |volume=55 |issue=3 |pages=623–640 |doi=10.1111/j.1475-4983.2012.01137.x|bibcode=2012Palgy..55..623B }} but possibly a stem-tetrapod,{{cite journal |last1=Marjanović |first1=David |last2=Laurin |first2=Michel |title=Phylogeny of Paleozoic limbed vertebrates reassessed through revision and expansion of the largest published relevant data matrix |journal=PeerJ |date=4 January 2019 |volume=6 |pages=e5565 |doi=10.7717/peerj.5565 |doi-access=free |pmid=30631641 |pmc=6322490 |language=en |issn=2167-8359}} from upper Permian (upper Tatarian age) deposits of Novgorod, Orenburg and Vologda Regions, Russia.{{cite journal |author=V. K. Golubev |year=1998 |title=Revision of the Late Permian Chroniosuchians (Amphibia, Anthracosauromorpha) from Eastern Europe |url=http://golubeff.narod.ru/PF/017e_Golubev_1998_Chroniosuchia_Permian_Russia.pdf |journal=Paleontological Journal |volume=32 |issue=4 |pages=390–401 }} It was first named by Tverdokhlebova in 1972 and the type species is Chroniosaurus dongusensis.

Its lifestyle is uncertain. An early study suggested a fairly aquatic lifestyle,{{cite journal |last1=Golubev |first1=V. K. |title=Narrow-armored chroniosuchians (Amphibia, Anthracosauromorpha) from the Late Permian of Eastern Europe |journal=Paleontological Journal |date=1998 |volume=32 |pages=278–287}} but its femoral microanatomy{{cite journal |last1=Laurin |first1=Michel |last2=Girondot |first2=Marc |last3=Loth |first3=Marie-Madeleine |title=The evolution of long bone microstructure and lifestyle in lissamphibians |journal=Paleobiology |date=December 2004 |volume=30 |issue=4 |pages=589–613 |doi=10.1666/0094-8373(2004)030<0589:TEOLBM>2.0.CO;2 |bibcode=2004Pbio...30..589L |url=https://doi.org/10.1666/0094-8373(2004)030<0589:TEOLBM>2.0.CO;2 |language=en |issn=0094-8373}} and dorsal dermal plates{{cite journal |last1=Buchwitz |first1=Michael |last2=Witzmann |first2=Florian |last3=Voigt |first3=Sebastian |last4=Golubev |first4=Valeriy |title=Osteoderm microstructure indicates the presence of a crocodylian-like trunk bracing system in a group of armoured basal tetrapods |journal=Acta Zoologica |date=July 2012 |volume=93 |issue=3 |pages=260–280 |doi=10.1111/j.1463-6395.2011.00502.x}} suggest a rather terrestrial lifestyle.