Utaturiceras
Encyclopedia
Utaturiceras is an upper Cretaceous (Cenomanian
) ammonitid
belonging to the family Acanthoceratidae
and subfamily Mantelliceratinae.
Utaturiceras is described in Matsumoto et al 2003 as having a fairly large shell at maturity, with a body chamber about half a whorl in length; whorls higher than broad and more or less involute; ribs in juvenile stage genly flexious and unequal in length, longer ones arising from bullate umbilical tubercles; shorter ones branched or intercalated; adult shell ornamented by equally long ribs and weakening tubercles. The suture has somewhat phylloid saddle endings.
Note that Matsumoto, et al, follow Cobban and Kennedy in referring to the Ammonoidea as an order in the Cephalopoda rather than as a subclass as often done.
Cenomanian
The Cenomanian is, in the ICS' geological timescale the oldest or earliest age of the Late Cretaceous epoch or the lowest stage of the Upper Cretaceous series. An age is a unit of geochronology: it is a unit of time; the stage is a unit in the stratigraphic column deposited during the corresponding...
) ammonitid
Ammonitida
The Ammonitida is an order of more highly evolved ammonoid cephalopods from the Jurassic and Cretaceous time periods, commonly with intricate ammonitic sutures....
belonging to the family Acanthoceratidae
Acanthoceratidae
Acanthoceratidae is an extinct family of cephalopods belonging to the Ammonite subclass. The Type genus is Acanthoceras.-Referenceas:*http://paleodb.org/cgi-bin/bridge.pl?action=checkTaxonInfo&taxon_no=95294&is_real_user=1...
and subfamily Mantelliceratinae.
Utaturiceras is described in Matsumoto et al 2003 as having a fairly large shell at maturity, with a body chamber about half a whorl in length; whorls higher than broad and more or less involute; ribs in juvenile stage genly flexious and unequal in length, longer ones arising from bullate umbilical tubercles; shorter ones branched or intercalated; adult shell ornamented by equally long ribs and weakening tubercles. The suture has somewhat phylloid saddle endings.
Note that Matsumoto, et al, follow Cobban and Kennedy in referring to the Ammonoidea as an order in the Cephalopoda rather than as a subclass as often done.
References
- Tatsuro Matsumoto, et al, 2003. Early Cenomanian (Cretaceous) ammonoids Utaturiceras and Graysonites from Hokkaido, North Japan. http://www.gsj.jp/Pub/Bull_new/vol_54/54_03/54_03_03.pdf Bulletin of the Geological Survey of Japan, vol.54
- Keith Young, 1958. Cenomanian (Cretaeous) Ammonites from Trans-Pecos Texas. Journal of Paleontology, v.32, no. 2, p 286-294, pls., text figs. March 1958. http://www.jstor.org/pss/1300735