PORT PHILLIP BAY


Hydroid 

Amphisbetia fasciculata (Kirchenpauer, 1864)

View scientific description and taxonomy

Scientific Details

Family level detail.
Colonies may be unbranched or branched and always with two rows of hydrothecae on opposite sides of stem, attached to stem and branches by part of their length. Hydrothecae bilaterally symmetrical, usually with a cuspate aperture with a segmented operculum. Gonophores are sporosacs female producing eggs and the male producing sperm, and protected by a gonotheca. The family Sertulariidae includes many genera and species and is known is a world-wide ranging from the tropics to arctic seas. They occur in all habitats from the intertidal zone to the deepest ocean and are very abundant in cool temperate seas southern Australia. Species range from small simple stems with a few hydrothecae to large, complexly branched pinnate colonies with hundreds of hydrothecae.

Genus level detail.
Colony branched or unbranched with two close-set rows of tubular hydrothecae, apertural margin of hydrotheca with two opposite, sharply pointed cusps. Several species of Amphisbetia are common southern Australia, some are small, simple stems and others are taller, pinnately branched stems.

Species identification.
Colonies that appear wiry and tangled, without a discernible main stem. Hydrothecae opposite on stem, tubular but not touching, apertural margin with two opposite, upwardly pointed sharp spines. Gonothecae scattered along branches, urn-shaped, flattened, with a circular terminal aperture surrounded by a raised collar. Colour: colony pale greenish to honey brown, often pink from a thin coating of coralline algae. Up to 25 cm high.

Taxonomy

Phylum:
Cnidaria
Class:
Hydrozoa
Subclass:
Leptothecatae
Order:
Conica
Family:
Sertulariidae
Genus:
Amphisbetia
Species:
fasciculata

General Description

Colony of individual polyps (hydranths) joined by root-like network of tubular stolons at the base. Colony shape is tree-like or bushy (arborescent). Colour: colony pale greenish to honey brown, often pink from a thin coating of coralline algae. Up to 25 cm high.

Biology

Colonies of this species grow during winter and early spring.

Habitat

Rubble sea floor in open areas with strong current flow.

Reefs

Distribution guide

Worldwide in temperate oceans, including southern Australia.

Species Group

Hydroids

Depth

Shallow (1-30 m)

Water Column

On or near sea floor

Max Size

25 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, Amphisbetia fasciculata, in Taxonomic Toolkit for marine life of Port Phillip Bay, Museum Victoria, accessed 25 Nov 2017, http://portphillipmarinelife.net.au:8098/species/7098

Text: creative commons cc by licence