Nostoceras

{{Short description|Genus of molluscs (fossil)}} {{Automatic taxobox | fossil_range = {{fossil range|Campanian|Maastrichtian|ref=<ref name="Sepkoski Ceph">{{cite web| last = Sepkoski| first = Jack| title = Sepkoski's Online Genus Database| author-link = | year = 2002| url = http://strata.geology.wisc.edu/jack/showgenera.php?taxon=231&rank=class| accessdate = 2023-12-14| archive-date = 2023-10-24| archive-url = https://web.archive.org/web/20231024101308/https://strata.geology.wisc.edu/jack/showgenera.php?taxon=231&rank=class| url-status = live}}</ref>}} | image = Nostoceras_species.JPG | taxon = Nostoceras | authority = Hyatt, 1894 | subdivision_ranks = Species | subdivision_ref = <ref name="fossilworks">{{cite web | title= Fossilworks - Nostoceras |author-link =| year = | url = https://paleobiodb.org/classic/checkTaxonInfo?taxon_no=15267 | access-date = 14 December 2023 }}</ref> | subdivision = {{collapsible list|bullets = true | ''N. adrotans'' | ''N. alternatus'' | ''N. approximans'' | ''N. arkanasanum'' | ''N. colubriformis'' | ''N. danei'' | ''N. draconis'' | ''N. helicinus'' | ''N. hyatti'' | ''N. kernense'' | ''N. mariatheresianum'' | ''N. mendryki'' | ''N. monotuberculatum'' | ''N. obtusum'' | ''N. pauper'' | ''N. pleurocostatum'' | ''N. pulcher'' | ''N. rotundum'' | ''N. saundersorum'' | ''N. splendidus'' | ''N. stantoni'' (type species)<ref name=Summesberger2007>{{cite journal|author=H. Summesberger, M. Machalski, M. Wagreich|year=2007|url=https://www.researchgate.net/publication/238717166|title=First record of the Late Campanian heteromorph ammonite ''Nostoceras hyatti'' from the Alpine Cretaceous (Grünbach, Gosau Group, Lower Austria)|journal=Acta Geologica Polonica |volume=57|issue=4|pages=443–451|doi=}}</ref>}} }}

'''''Nostoceras''''' is an extinct genus of ammonites. The genus name comes from Ancient Greek νόστος (''nóstos''), meaning "return", and κέρας (''céras''), meaning "horn",{{Citation needed|reason=Ceros is pseudo-Greek as the ancient Greek nominative is κέρας. Or did Hyatt used this incorrect derivation?|date=May 2018}} named as such by Alpheus Hyatt because the species' shell bends back on itself.

==Taxonomy== ''Nostoceras'' is the type genus for the ammonite family Nostoceratidae which is included in the Turrilitoidea.<ref name=Summesberger2007/> The Turrilitoidea, with ''Nostoceras'' and the Nostoceratidae, are commonly included in the suborder Ancyloceratina but may instead belong in the Turrilitina, a proposed order of heteromorphs thought to have a separate derivation, though this separation does not have wide support.

==Fossil record== Fossils of ''Nostoceras'' are found in marine strata from the Campanian stage of the Upper Cretaceous, in the USA, Mexico, Europe (England, the Netherlands, Austria, Belgium, Denmark, France, Germany, Spain, Italy), Tajikistan, Turkmenistan, Uzbekistan, Iraq, Oman, Africa (South Africa, Angola, Nigeria), Madagascar, Australia and Japan.<ref name="fossilworks"/>

== Description == ''Nostoceras'' is typified by a tightly coiled helical spire on a large U-shaped body chamber with the aperture, in mature individuals, nearly touching and lying underneath the spire.<ref name=Summesberger2007/> The initial helical whorls are covered with fine ribs and may have small spines. The U-shaped body chamber has coarser ribbing and large tubercles. Periodic constrictions may be present on the phragmocone. Species may coil either to the left or to the right. ''Nostoceras'' is like ''Bostrychoceras'' in general form, except that its ribs may be flared and the constrictions may or may not be present.

''Nostoceras hyatti'' could reach 90 mm in length.<ref name=Summesberger2007/>

<gallery widths="240" heights="180"> File: Nostoceras hetonaiense - National Museum of Nature and Science, Tokyo - DSC06975.JPG|''Nostoceras hetonaiense'' File: Nostoceratidae - Nostoceras malagasyense.JPG|Fossils of ''Nostoceras malagasyense'' from Campanian of Tulear (Madagascar) </gallery>

==Sources== ;Notes {{Reflist}} ;Bibliography * Arkell ''et al.'', 1957. Mesozoic Ammonoidea, Treatise on Invertebrate Paleontology, Part L. Geol Soc. of Amer. and Univ. Kans. press. * Larson, Neal L. 2012. The Late Campanian (Upper Cretaceous) Cephalopod Fauna of the Coon Creek Formation at the Type Locality. The Journal of Paleontological Sciences: JPS.H.2012.01. [http://www.aaps-journal.org/journal-contributions.html]  * ''A Pictorial Guide to Fossils'' by Gerard Ramon Case

Category:Ammonitida genera Category:Nostoceratidae Category:Fossil taxa described in 1894 Category:Late Cretaceous ammonites of Europe Category:Ammonites of Africa Category:Ammonites of Australia Category:Late Cretaceous ammonites of North America Category:Campanian genus first appearances Category:Maastrichtian genus extinctions Category:Fossils of Turkmenistan