Paratropical subsea
A Paratropical subsea is a high-latitude body of water within a paratropical province and one in which the temperature regularly falls below 20 °C (68 °F), but not below 10 °C (50 °F) which is considered sub-tropical. Paratropical subseas are distributed equally polewards of eutropical subseas.
Paratropical subseas are absent of corals and well-developed carbonate beds and seagrass, yet contain a mixture of Tethys Ocean lineages of the Eocene as well as Boreal and anti-Boreal (Southern Hemisphere) taxa. This marine environment supports a single species of a few mollusks found in eutropical subseas. Brittle stars, Turridae, Cassis, Euspira, and the rock snails Muricidae thrive in paratropical subseas.
References
Primary source: Petuch, Edward J., Cenozoic seas: the view from eastern North America, ISBN 0-8493-1632-4, ISBN 978-0-8493-1632-6.