PORT PHILLIP BAY


Hydroid 

Sertularella unguiculata (Busk, 1852)

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.
Colonies branched or unbranched, hydrothecae alternate, attached at base to stem or branches, apertural margin with four cusps, operculum pyramidal, gonotheca barrel-shaped, surface ridged. Sertularella is a common southern Australian genus. Some species have simple stems while others are large, showy colonies.

Species identification.
Hyrorhizal stolons creeping over substrate. Stems pinnate, unbranched, growing in small clumps. Stem fairly thick, arched slightly backwards, hydrocladia alternate. Hydrothecae opposite on hydrocladia, tubular, almost touching, bent abruptly outwards, tapering to margin, aperture with a pair of blunt lateral cusps. Gonothecae borne along stem, barrel-shaped, smooth, with a circular terminal aperture surrounded by a short raised collar. Colour: golden-brown. Up to 4 cm long.

Taxonomy

Phylum:
Cnidaria
Class:
Hydrozoa
Subclass:
Leptothecatae
Order:
Conica
Family:
Sertulariidae
Genus:
Sertularella
Species:
unguiculata

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: golden-brown. Up to 4 cm long.

Biology

Colonies of these hydroids appear in winter. They become fertile in spring and summer.

Habitat

On sponges and other invertebrates in sheltered oceanic waters.

Reefs

Distribution guide

New Zealand, Antarctica and south-eastern Australia.

Species Group

Hydroids

Depth

Shallow (1-30 m)

Water Column

On or near sea floor

Max Size

4 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, Sertularella unguiculata, in Taxonomic Toolkit for marine life of Port Phillip Bay, Museum Victoria, accessed 23 Aug 2017, http://portphillipmarinelife.net.au:8098/species/7106

Text: creative commons cc by licence