{{Short description|Extinct genus of molluscs}} {{Automatic taxobox | fossil_range = Middle-Late Triassic (Nor) | image = | image_caption = | taxon = Styrionautilus | authority = Mojsisovics, 1902 }}
'''''Styrionautilus''''' is a genus of nautiloids and first of the Clydonautilidae with a range extending from the Middle Triassic, Anisian to the Upper Triassic, Norian. Its fossils have been found in North America (Nevada), Europe, and Timor.
In general form '''''Styrionautilus''''' is similar to other clydonautilids, smooth and involute. The suture however is more primitive. The ventral saddle is straight across without modification of a median lobe.
''Styrionautilus'' may be derived from ''Indionautilus'' or similar form included in the Liroceratidae. In turn ''Styrionautilus'' is the likely ancestor of ''Proclydonautilus'', ''Cosmonautilus'', and/or ''Callaionautilus''
==References== {{Reflist}} * Bernhard Kummel, 1964. Nautiloidea-Nautilida. Treatise on Invertebrate Paleontology, Part K. Geological Society of America. * [https://paleobiodb.org/classic/checkTaxonInfo?taxon_no=13307 ''Styrionautilus''] in Fossilworks gateway. * J.J. Sepkoski 2002 [http://strata.geology.wisc.edu/jack/showgenera.php?taxon=231&rank=class Online list of cephalopod genera]
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Category:Prehistoric nautiloid genera Category:Anisian genus first appearances Category:Ladinian genera Category:Carnian genera Category:Norian genus extinctions Category:Anisian life
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