''Tithonoceras'' is a genus of
nautiloid cephalopod
A cephalopod is any member of the molluscan class Cephalopoda (Greek plural , ; "head-feet") such as a squid, octopus, cuttlefish, or nautilus. These exclusively marine animals are characterized by bilateral body symmetry, a prominent head ...
from the Upper
Jurassic
The Jurassic ( ) is a Geological period, geologic period and System (stratigraphy), stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately Mya. The J ...
(Thithonian stage) found in the
Crimea
Crimea, crh, Къырым, Qırım, grc, Κιμμερία / Ταυρική, translit=Kimmería / Taurikḗ ( ) is a peninsula in Ukraine, on the northern coast of the Black Sea, that has been occupied by Russia since 2014. It has a pop ...
, belonging to the
nautilacean family
Paracenoceratidae
The Paracenoceratidae are an extinct family of prehistoric nautiloids. The cephalopods lived during the Jurassic and Cretaceous
The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the thi ...
.
The shell of ''Tithonoceras'' is
evolute, coiled with all whorls exposed, smooth, and laterally compressed. The whorl section is subquadrangular with a broad, flattened venter on the outer rim.
Ventrolateral
Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position prov ...
shoulders are inflated, forming broad, rounded, keels, bordered by broad furrows on the flanks. The
suture is sinuous, with ventral and lateral lobes. The position of the
siphuncle
The siphuncle is a strand of tissue passing longitudinally through the shell of a cephalopod mollusk. Only cephalopods with chambered shells have siphuncles, such as the extinct ammonites and belemnites, and the living nautiluses, cuttlefish, and ...
is unknown.
References
* Barnhard , 1964. Nautiloidea-Nautilida. Treatise on Invertebrate Paleontology, Part K. Geol. Soc. of America and Univ. Kansas Press.
* Paleobiology databas
Tithonoceras* Sepkoski, 2002
Cephalopod genera
Prehistoric nautiloid genera
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