''Hexagonites'' is an extinct genus from the nautiloid order,

Nautilida The Nautilida constitute a large and diverse order of generally coiled nautiloid cephalopods that began in the mid Paleozoic and continues to the present with a single family, the Nautilidae which includes two genera, ''Nautilus'' and ''Allonauti ...

which includes the genus ''

Nautilus A nautilus (; ) is any of the various species within the cephalopod family Nautilidae. This is the sole extant family of the superfamily Nautilaceae and the suborder Nautilina. It comprises nine living species in two genera, the type genus, ty ...

'' currently found living in the tropical western

Pacific The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean, or, depending on the definition, to Antarctica in the south, and is bounded by the cont ...

. ''Hexagonites'' is included in the family

Tainoceratidae Tainoceratidae is a family of late Paleozoic and Triassic nautiloids that are a part of the order Nautilida, characterized by large, generally evolute shells with quadrate to rectangular whorl sections. Shells may bear ribs or nodes, or both. ...

, part of the superfamily

Tainoceratoidea The Tainoceratoidea are a superfamily in the cephalopod order Nautilida characterized by straight to loosely coiled shells, generally to a degree such that the width is greater than the height, to quadrate whorl section. Many bore spines, ribs, f ...

(Kummel, 1964) ''Hexagonites'' is based on an incomplete, crushed specimen from the

Permian The Permian ( ) is a geologic period and System (stratigraphy), stratigraphic system which spans 47 million years, from the end of the Carboniferous Period million years ago (Mya), to the beginning of the Triassic Period 251.902 Mya. It is the s ...

of China. Its shell is very evolute, with an hexagonal whorl section, and six rows of

tubercle In anatomy, a tubercle (literally 'small tuber', Latin for 'lump') is any round nodule, small eminence, or warty outgrowth found on external or internal organs of a plant or an animal. In plants A tubercle is generally a wart-like projectio ...

s, in pairs on the

ventrolateral Standard anatomical terms of location are used to describe unambiguously the anatomy of humans and other animals. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position provi ...

and

dorsolateral Standard anatomical terms of location are used to describe unambiguously the anatomy of humans and other animals. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position provi ...

shoulders. The suture has shallow lobes. (ibid)

References

* Kummel,B. 1964. Nautilioidea - Nautilida, in the

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 K Nautiloidea, Geological Society of America and University of Kansas press.
Sepkosk's list of Cephalopod genera
Prehistoric nautiloid genera Nautiloids {{paleo-Nautiloidea-stub