PORT PHILLIP BAY


Hydroid 

Plumularia setacea (Linnaeus, 1758)

View scientific description and taxonomy

Scientific Details

Family level detail.
Hydroids branched or unbranched, pinnate, usually with alternate hydrocladia, hydrotheca cup-shaped, one nematotheca in front of hydrotheca and one on each side behind hydrotheca. Gonophores protected by a gonotheca female gonophore producing eggs. The family Plumulariidae encompasses many genera and species world-wide, from shallow to deep water. Species range from very small fast growing colonies to large colonies that may live for many years.

Genus level detail.
Colonies pinnate, hydrocladia alternate on stem internodes, each hydrocladium bearing several hydrothecae and divided into segments (internodes) alternately with and without hydrothecae. Hydrotheca on thecate segment, cup-shaped, with one wine-glass-shaped median nematotheca in front and two (twin laterals) at margin of hydrotheca. Athecate segment Internode with one or more median nematothecae. Gonothecae borne on stem and branches.

Species identification.
Stems pinnate, growing singly or in clusters from hydrorhiza. Hydrocladia about 5 mm long, with many hydrothecae. An athecate internode separating thecate internodes. Hydrotheca cup-shaped, basal side entirely fixed to internode, apertural rim circular, facing forward. One nematotheca in front of hydrotheca and one each at side of hydrothecal rim (twin laterals). Gonothecae in a row along stem, narrow flask-shaped with a long, tubular terminal neck, sometimes bent. Female gonophores with eggs. Can be confused with Nemertesia wattsi, the difference being taller colonies and spiral hydrocladia of N. wattsi. Colour: stems pale brown, hydrocladia white, gonotheca white. Up to 10 cm high.

Taxonomy

Phylum:
Cnidaria
Class:
Hydrozoa
Subclass:
Leptothecatae
Order:
Conica
Family:
Plumulariidae
Genus:
Plumularia
Species:
setacea

General Description

Colony of individual polyps (hydranths) joined by root-like network of tubular stolons at the base. Colony shape is feather-like (pinnate). Colour: stems pale brown, hydrocladia white, gonotheca white. Up to 10 cm high.

Biology

These hydroids were distributed around the world possibly on ships. Their colonies become fertile over summer.

Habitat

Sheltered bays, often on jetty piles.

Reefs

Distribution guide

Worldwide.

Species Group

Hydroids

Depth

Shallow (1-30 m)

Water Column

On or near sea floor

Max Size

10 cm

Diet

Plankton or Particles

Harmful

Generally not harmful but still able to sting bare skin.

Commercial Species

No

Global Dispersal

Recorded in Australia

Identify

Conservation Status

  • DSE Advisory List : Not listed
  • EPBC Act 1999 : Not listed
  • IUCN Red List : Not listed

Author

article author Watson, J.

Jan Watson is a consultant with expertise in hydroid taxonomy.

citation

Cite this page as:
Watson, J., 2011, Hydroid, Plumularia setacea, in Taxonomic Toolkit for marine life of Port Phillip Bay, Museum Victoria, accessed 23 Aug 2017, http://portphillipmarinelife.net.au:8098/species/7135

Text: creative commons cc by licence