Tentaculites

Tentaculites is an extinct genus of conical fossils of uncertain affinity, class Tentaculita, although it is not the only member of the class. It is 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.

Tentaculites Temporal range: Early Ordovician – Late Devonian[1] PreꞒ Ꞓ O S D C P T J K Pg N
Tentaculitids from the Devonian of Maryland.
Scientific classification
Kingdom:	Animalia
Class:	†Tentaculita
Order:	†Tentaculitida
Family:	†Tentaculitidae
Genus:	†Tentaculites von Schlotheim 1820

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, Anticalyptraea, microconchids and trypanoporids.[6] Their shell microstructure has warranted their comparison with the brachiopods and phoronids,[2][7] and the possible Ediacaran lophophorate Namacalathus.[8]

Morphology

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

Tentaculites bellulus from the Middle Devonian of Wisconsin.

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.[9]

References

1. Traverse, A. (2007). "What Paleopalynology Is and Is Not". Paleopalynology. Topics in Geobiology. 28. pp. 1–43. 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: 111–116. 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 (1–2): 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 (2): 145–156. doi:10.1080/11035897.2012.669788. Retrieved 2014-06-11.
8. 1. Zhuravlev, A.Y., Wood, R.A., and Penny, A.M. (2015). Ediacaran skeletal metazoan interpreted as a lophophorate. Proc. R. Soc. B 282, 20151860. Available at: http://rspb.royalsocietypublishing.org/lookup/doi/10.1098/rspb.2015.1860.
9. 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