Tentaculites

Tentaculites Temporal range: Early Ordovician – Late Devonian[1] PreЄ Є O S D C P T J K Pg N
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 of conical fossils of uncertain affinity, known from Lower Ordovician to Upper Devonian deposits^[1] both as calcitic shells with a brachiopod-like microstructure^[2] and carbonaceous 'linings'.^[3][4] 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.^[5] They may also be related to other conical shells of uncertain affinity including cornulitids, microconchids and trypanoporids.^[6] Their shell microstructure has warranted their comparison with the brachiopods and phoronids.^[2][7]

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.^[4]

Ecology

Some species are inferred to have been planktonic.^[8]

References

1. Traverse, A. (2007). "What Paleopalynology Is and Is Not". Paleopalynology. Topics in Geobiology 28. pp. 1–1. doi:10.1007/978-1-4020-5610-9_1. ISBN 978-1-4020-6684-9.
2. Towe, K. M. (1978). "Tentaculites: Evidence for a Brachiopod Affinity?". Science 201 (4356): 626–628. doi:10.1126/science.201.4356.626. PMID 17794124.
3. Wood, G.D., Miller, M.A., and Bergstrom, S.M. 2004. Late Devonian (Frasnian) tentaculite organic remains in palynological preparations, Radom−Lublin region, Poland. Memoirs of the Association of Australian Palaeontologists 29: 253–258.
4. Filipiak, P.; Jarzynka, A. (2009). "Organic Remains of Tentaculitids: New Evidence from Upper Devonian of Poland". Acta Palaeontologica Polonica 54: 111. doi:10.4202/app.2009.0111.
5. Ager, 1963, Principles of Palaeontology
6. Vinn, O. (2010). "Adaptive strategies in the evolution of encrusting tentaculitoid tubeworms". Palaeogeography Palaeoclimatology Palaeoecology 292: 211–221. doi:10.1016/j.palaeo.2010.03.046. Retrieved 2014-01-11.
7. Vinn, O.; Zatoń, M. (2012). "Phenetic phylogenetics of tentaculitoids — extinct problematic calcareous tube-forming organisms". GFF 134: 145–156. doi:10.1080/11035897.2012.669788. Retrieved 2014-06-11.
8. LARSSON K. (1979). "Silurian tentaculitids from Gotland and Scania". Fossils and Strata 11: 180.

Further reading

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

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