Biodiversity & Conservation

A hydroid - Thieliana navis - General information

Thieliana navis

Image Marco Faasse - Thieliana navis on Ruppia, Goesse Meer, The Netherlands. Image width ca XX cm.
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Distribution map

Thieliana navis recorded (dark blue bullet) and expected (light blue bullet) distribution in Britain and Ireland (see below)

Why do the maps differ?

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  • WC_Act_1981

General information

Key Icon Researched by: Nicola White Text page icon Refereed by: Dr Richard S.K. Barnes

Taxonomy icon Taxonomy

Phylum Cnidaria Sea anemones, corals, sea firs & jellyfish
Class Hydroidomedusa
Map icon Recorded distribution in Britain and Ireland Widewater lagoon, West Sussex.
Habitat information icon Habitat information Grows on algae such as Chaetomorpha. It has only ever been recorded in the vicinity of ports and harbours.
Text page icon Description A simple hydroid consisting of an erect, unbranched stem, up to 5 mm in height, with a single terminal polyp (hydranth) . Each upright stem rises from a creeping stolon (hydrorhiza). The stem is sheathed by a chitinous sheath, the perisarc. The perisarc is often wrinkled, especially near the base, and terminates below the hydranth. The hydranth bears 8 to 16 tentacles in 2 to 4 alternating whorls, depending on hydranth size. It is creamy white in colour, with hints of pink around the mouth of the hydranth. The reproductive bodies (gonophores) are borne on short stalks in an irregular spiral below the hydranth.

This review can be cited as follows:

Nicola White 2005. Thieliana navis. A hydroid. Marine Life Information Network: Biology and Sensitivity Key Information Sub-programme [on-line]. Plymouth: Marine Biological Association of the United Kingdom. [cited 25/05/2013]. Available from: <http://www.marlin.ac.uk/speciesfullreview.php?speciesID=4461>