''Nipponites'' is an extinct

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

heteromorph The Ancyloceratina were a diverse suborder of ammonite most closely related to the ammonites of order Lytoceratina. They evolved during the Late Jurassic but were not very common until the Cretaceous period, when they rapidly diversified and bec ...

ammonite Ammonoids are a group of extinct marine mollusc animals in the subclass Ammonoidea of the class Cephalopoda. These molluscs, commonly referred to as ammonites, are more closely related to living coleoids (i.e., octopuses, squid and cuttlefish) ...

s. The shells of ''Nipponites'' (primarily ''N. mirabilis'') form "ox-bow" bends, resulting in some of the most bizarre shapes seen among ammonites. The ecology of ''Nipponites'', as with many other nostoceratids, is subject to much speculation.

Distribution

Fossils of most species are found primarily in

Upper Cretaceous The Late Cretaceous (100.5–66 Ma) is the younger of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''creta'', the ...

strata of Japan. ''N. mirabilis'' is found in

Coniacian The Coniacian is an age or stage in the geologic timescale. It is a subdivision of the Late Cretaceous Epoch or Upper Cretaceous Series and spans the time between 89.8 ± 1 Ma and 86.3 ± 0.7 Ma (million years ago). The Coniacian is preceded by t ...

-aged strata of Japan and possibly

Turonian The Turonian is, in the ICS' geologic timescale, the second age in the Late Cretaceous Epoch, or a stage in the Upper Cretaceous Series. It spans the time between 93.9 ± 0.8 Ma and 89.8 ± 1 Ma (million years ago). The Turonian is preceded by t ...

-aged strata in Madagascar. ''N. bacchus'' is found in Upper Cretaceous Hokkaido. Two species are found exclusively outside Japan, ''N. sachalinensis'', which is found in Upper Cretaceous strata of Sakhalin island, and Kamchatka peninsula,Shigeta, Yasunari, and Haruyoshi Maeda. "Yezo Group research in Sakhalin—a historical review." National Science Museum Monographs 31 (2005): 1-24. and ''N. occidentalis'', which is known from two shells found in the

-aged Hornbrook Formation of Southern Oregon.Ward, Peter D., and Gerd EG Westermann. "First occurrence, systematics, and functional morphology of Nipponites (Cretaceous Lytoceratina) from the Americas." Journal of Paleontology (1977): 367-372.

Image gallery

File:Nipponites mirabilis1.jpg, ''N. mirabilis'' File:Nipponites mirabilis & Ainoceras kamuy.jpg, ''N. mirabilis'' File:Nipponites mirabilis 2.jpg, ''N. mirabilis''

References

;Notes ;Bibliography * Ammonitida genera Nostoceratidae Cretaceous ammonites Ammonites of Asia Ammonites of Africa Prehistoric animals of Madagascar Turonian genus first appearances Coniacian genus extinctions Fossil taxa described in 1902 {{Ammonitida-stub