PORT PHILLIP BAY


Hydroid 

Halecium delicatulum Coughtrey, 1876

View scientific description and taxonomy

Scientific Details

Family level detail.
Hydroids with a shallow saucer-shaped hydrotheca too small to contain the contracted hydranth. Gonothecae containing sperm and eggs. Colonies range in size from minute single hydrothecae to tall lacey bushes. Many species are cryptic, growing in crevices, while others grow in light on other invertebrates and algae. Depth range of the family is from shallow waters to the deep sea.

Species identification.
Profusely branched lacy colonies growing from hydrorhiza creeping on substrate. Hydrotheca shallow saucer-shaped, each on a short pedicel on branch, rim circular, everted. Hydranth much larger than hydrotheca with a ring of stubby tentacles. Gonothecae numerous oval, flattened, mature female with an indentation in the summit, male peaked; female packed with eggs, male with sperm. Can be confused with Halopteris campanula which has a similar habit and colour but the saucer-shaped hydrothecae of H. delicatulum are diagnostic. Colour: variable pale yellow to orange, gonothecae orange or pinkish. Up to 5 cm high.

Taxonomy

Phylum:
Cnidaria
Class:
Hydrozoa
Subclass:
Leptothecatae
Order:
Conica
Family:
Haleciidae
Genus:
Halecium
Species:
delicatulum

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: variable pale yellow to orange, gonothecae orange or pinkish. Up to 5 cm high.

Biology

Colonies of this species grow annually and become fertile in spring and summer.

Habitat

Still water on invertebrates, often on sponges and algae attached to jetties, to depths greater than 500 m.

Reefs

Distribution guide

Temperate to subantarctic waters worldwide. Southern Australia.

Species Group

Hydroids

Depth

Shallow (1-30 m)
Deep ( > 30 m)

Water Column

On or near sea floor

Max Size

5 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, Halecium delicatulum, in Taxonomic Toolkit for marine life of Port Phillip Bay, Museum Victoria, accessed 29 Jun 2017, http://portphillipmarinelife.net.au:8098/species/7127

Text: creative commons cc by licence