PORT PHILLIP BAY


Hydroid 

Sertularella robusta Coughtrey, 1876

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.
Hydrorhiza creeping across substrate. Colonies simple, usually unbranched. Hydrothecae alternate, base adnate, free part pointing outwards, usually ridged, apertural margin with four low cusps, three small bracket-like teeth inside the margin spaced between the cusps. Gonotheca barrel-shaped, borne on lower stem, concentrically ridged, summit with a neck with three or four upwardly pointing short spines. Colour: pale honey brown to yellow. Up to 1 cm high.

Taxonomy

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

General Description

Colony of individual polyps (hydranths) joined by root-like network of tubular stolons at the base. Colony shape is single stems. Colour: pale honey brown to yellow. Up to 1 cm high.

Biology

Colonies of this species grow throughout the year, and are fertile in summer months. They are common in sheltered ocean areas and bays.

Habitat

On surfaces with seaweed and invertebrates.

Reefs

Distribution guide

Worldwide. Southern Australia.

Species Group

Hydroids

Depth

Shallow (1-30 m)

Water Column

On or near sea floor

Max Size

1 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 robusta, in Taxonomic Toolkit for marine life of Port Phillip Bay, Museum Victoria, accessed 16 Dec 2017, http://portphillipmarinelife.net.au:8098/species/7112

Text: creative commons cc by licence