Trachyteuthis

Trachyteuthis is a genus of fossil cephalopod, comprising five species: T. hastiformis, T. latipinnis, T. nusplingensis, T. teudopsiformis, T. covacevichi and T. chilensis.
Taxonomy.
The taxonomic placement of "Trachyteuthis" is uncertain. Though often assigned to the order Vampyromorphida, the discovery of fossilised "Trachyteuthis" beaks in the Upper Jurassic limestone of Germany suggests a close phylogenetic relation to the Octopoda. It is clear that it does at least belong in the Coleoidea. It is thought to be very closely related to "Teudopsis".
Distribution.
Fossils are scarce but have been reported from the Kimmeridge clay of the UK; the Solnhofen limestone of Germany, Jurassic deposits in Antarctica, and Oxfordian deposits in Chile.
History.
First described in 1773 as the remnants of a fish, "Trachyteuthis" was considered comparable to a "Sepia" cuttlebone by Rüppell in 1829. A separate genus was erected for the material in 1846 by Meyer. English material discovered in 1855 was termed "Coccoteuthis latipinnis"; this was later synonymised with the identical Solnhofen deposits. A 2007 survey of museum collection established that there were ground for the erection of three species within the genus.