''Acrochordiceras'' is a genus of

Middle Triassic In the geologic timescale, the Middle Triassic is the second of three epoch (geology), epochs of the Triassic period (geology), period or the middle of three series (stratigraphy), series in which the Triassic system (stratigraphy), system is di ...

ammonoid Ammonoids are extinct, (typically) coiled-shelled cephalopods comprising the subclass Ammonoidea. They are more closely related to living octopuses, squid, and cuttlefish (which comprise the clade Coleoidea) than they are to nautiluses (family N ...

cephalopods belonging to the

ceratitid Ceratitida is an order that contains almost all ammonoid cephalopod genera from the Triassic as well as ancestral forms from the Upper Permian, the exception being the phylloceratids which gave rise to the great diversity of post-Triassic ammon ...

family Acrochordiceratidae, included in the superfamily

Ceratitoidea Ceratitoidea, formerly Ceratitaceae, is an ammonite superfamily in order Ceratitida characterized in general by highly ornamented or tubercle, tuberculate shells with ceratitic Suture (anatomy), sutures that may become goniatitic or ammonitic in ...

. The shell of ''Acrochordiceras'', as with the family, is more or less involute with strong, almost transverse, ribs that cross the arched venter uninterrupted. The ventral lobe is bifid. The first lateral lobe is larger than the other and is multi-pronged. Prongs on subsequent smaller lobes are less developed and saddles are small and rounded. ''Acrochordiceras'' was described by Hyatt in 1877 and is known from

Eurasia Eurasia ( , ) is a continental area on Earth, comprising all of Europe and Asia. According to some geographers, Physical geography, physiographically, Eurasia is a single supercontinent. The concept of Europe and Asia as distinct continents d ...

Timur Timur, also known as Tamerlane (1320s17/18 February 1405), was a Turco-Mongol conqueror who founded the Timurid Empire in and around modern-day Afghanistan, Iran, and Central Asia, becoming the first ruler of the Timurid dynasty. An undefeat ...

California California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...

and

Nevada Nevada ( ; ) is a landlocked state in the Western United States. It borders Oregon to the northwest, Idaho to the northeast, California to the west, Arizona to the southeast, and Utah to the east. Nevada is the seventh-most extensive, th ...

References

* Arkell, ''et al''., 1957. Mesozoic Ammonoidea;

Treatise on Invertebrate Paleontology The ''Treatise on Invertebrate Paleontology,'' published from 1953–2007 by the Geological Society of America and the University of Kansas, then 2009–present by the University of Kansas Paleontological Institute, is a definitive multi-authore ...

, Part L, Ammonoidea. Geol. Soc. of America and Univ. Kans. Press. Ceratitoidea Ceratitida genera Fossil taxa described in 1877 Triassic ammonites of North America Middle Triassic life Middle Triassic genus first appearances Middle Triassic genus extinctions {{Ceratitida-stub