PORT PHILLIP BAY


Hydroid 

Clytia hemisphaerica (Linnaeus, 1767)

View scientific description and taxonomy

Scientific Details

Family level detail.
Hydroids with a simple bell-shaped (campanulate) hydrotheca without operculum. Apertural rim of hydrotheca may be smooth, toothed, crenulated or cuspate. Gonophores protected by a gonotheca. Hydroids of the family Campanulariidae are common throughout the world. Many species form large, spreading colonies comprising many simple stems arising from a creeping network of stolons. Other species from large, multi-branched colonies, usually lacy in appearance. Medusae range in structure from primitive eumedusoids that swim only feebly to fully formed free-swimming medusae.

Genus level detail.
Colony stolonal, unbranched, hydrotheca campanulate to conical, radially symmetrical with a diaphragm (internal transverse partition across base of hydrotheca) a deeply cuspate (toothed) aperture, gonophores producing free-swimming medusae. There are several southern Australian species of Clytia, some simple and pedicellate while others are branched. The pedicellate species are all similar in structure and can only be distinguished with microscopic examination.

Species identification.
Colonies consisting of a few to many hydrothecae. Hydrorhiza of thin tubular stolons connecting the pedicels (stems). Pedicels tubular, annulated at base and below the hydrotheca. Stems sometimes with a single branch. Hydrotheca small, campanulate, borne at top of pedicel, aperture deeply cuspate. Gonotheca borne on hydrorhiza, barrel-shaped, smooth to slightly corrugated, containing several developing medusae, the most mature at top. Medusa at release saucer-shaped, less than 1 mm in diameter with a fringe of short tentacles and a small mouth (manubrium) in the centre of the bell. Medusae swim inside-out with feeble jerky movements. Species distinguished by microscopic examination of the rim of the hydrotheca. Colourless. Up to 5 mm long.

Taxonomy

Phylum:
Cnidaria
Class:
Hydrozoa
Subclass:
Leptothecatae
Order:
Proboscoida
Family:
Campanulariidae
Genus:
Clytia
Species:
hemisphaerica

General Description

Colony of individual polyps (hydranths) joined by root-like network of tubular stolons at the base. Colony shape is single stems. Colourless. Up to 5 mm long.

Biology

Colonies of this species are present and fertile most of year. They are common in ports around the globe.

Habitat

On invertebrates and algae, mostly in sheltered waters.

Reefs

Distribution guide

Worldwide.

Species Group

Hydroids

Depth

Shallow (1-30 m)

Water Column

On or near sea floor

Max Size

5 mm

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, Clytia hemisphaerica, in Taxonomic Toolkit for marine life of Port Phillip Bay, Museum Victoria, accessed 17 Aug 2017, http://portphillipmarinelife.net.au:8098/species/7124

Text: creative commons cc by licence