Tentaculites

Tentaculites Temporal range: Early Ordovician – Late Devonian PreЄ Є O S D C P T J K Pg N
File:TentaculitidDevonian.jpg
Tentaculitids from the Devonian of Maryland.
Scientific classification
Kingdom:	Animalia
Phylum:	Mollusca (?)
Class:	†Tentaculita
Order:	†Tentaculitida
Family:	†Tentaculitidae
Genus:	†Tentaculites von Schlotheim 1820

Tentaculites is an extinct genus conical fossil of uncertain affinity, known from Lower Ordovician to Upper Devonian deposits both as calcitic shells with a brachiopod-like microstructure and carbonaceous 'linings'. The "tentaculites" (i.e. tentaculita) are also referred to as the styliolinids.

Affinity

The taxonomic classification of tentaculitids is uncertain, but some group them with pteropods. They may also be related to other conical shells of uncertain affinity including cornulitids, microconchids and trypanoporids. Their shell microstructure has warranted their comparison with the brachiopods and phoronids.

Morphology

Tentaculitids have ribbed, cone-shaped shells which range in length from 5 to 20 mm. Some species septate; their embryonic shell, which is retained, forms a small, sometimes spherical, chamber.

Ecology

Some species are inferred to have been planktonic.

Further reading

• Treatise on Invertebrate Paleontology, Part W - Miscellanea. Geological Society of America and University of Kansas Press, 1962. LCCN 53012913

File:Tentaculitid041011.jpg

Tentaculitid from the New Creek Limestone (Lochkovian, Early Devonian) of New Creek, West Virginia.