Echinoderms

Marine Life in Port Phillip Bay and around the world

ECHINODERMS

General

  • Greek “Echinos” meaning “spiny” and “dermos” meaning “skin"
  • Approximately 7,000 species
  • Includes starfish, sea urchins, sand dollars, sea cucumbers, sea lillies

 Distribution

  • Exclusively marine animals, no freshwater

 Habitat

  • Benthic animals
  • Found usually on the sea floor in every marine habitat from the intertidal zone to ocean depths

 Body

  • They are triploblastic.
  • Larval form show bilateral symmetry and adult forms show radial symmetry
  • Body is unsegmented without a head
  • The body is uniquely shaped. It can be star like, elongated or spherical

 Reproduction

  • Sexes are separate, Echinoderms are either male or female
  • Become sexually mature after about two to three years
  • Most release their eggs and sperm into the water where they are fertilized externally
  • A female can release one hundred million eggs at once
 

Divided into:

 Subphylum:  Asterozoa

     Class  Asteroidea            Sea Stars & starfishes 

     Class  Ophiuroidea         Brittle Stars

 Subphylum:  Crinozoa

     Class  Crinoidea              Sea Lilies & Feather Stars

 Subphylum:  Echinozoa

     Class  Echinoidea           Sea Urchins and Sand Dollar

     Class  Holothuroidea     Sea Cucumbers

 
 
 

SUBPHYLYUM: ASTEROZOA

CLASS: ASTEROIDEA

 

Scientific Name: Asterias amurensis   (Lütken, 1871)

Common Name: Northern Pacific Sea Star

Coscinasterias muricata

Photo by Paul Sorensen. Victoria, Mornington Pier, 2009. Introduced species. 

 

 

Scientific Name: Coscinasterias muricata  (Verrill, 1867)

Common Name: Eleven Arm Seastar

Coscinasterias muricata

Photo by Paul Sorensen. Victoria, Blairgowrie Pier, 2013.

 

 

Scientific Name: Uniophora granifera  (Lamarck, 1816)

Common Name: Granular Sea Star

Uniophora granifera

Photo by Paul Sorensen. Victoria, Mornington Pier, October 2020.

 Uniphora granifera

Photo by Paul Sorensen. Victoria, Blairgowrie Pier, February 2020.

 

 

Scientific Name:   Echinaster luzonicus  (Gray, 1840)

Common Name:   Luzon Sea Star

Echinaster luzonicus

Photo by Paul Sorensen. Philippines, Puerto Galera, October 2018.

 

Scientific Name: Petricia vernicina   (Lamarck, 1816)

Common Name: Velvet Sea Star

Petricia vernicina

Photo by Paul Sorensen. Victoria, Mornington Pier, October 2009.

Petricia vernicina

Photo by Paul Sorensen. Victoria, Ricketts Point, November 2020

Petricia vernicina

Photo by Paul Sorensen. Victoria, Ricketts Point, November 2020.

 

Scientific Name: Nectria ocellata  Perrier, 1925

Common Name: Spotted Sea Star

 Nectria ocellata

Photo by Paul Sorensen. Victoria, Point Lonsdale, June 2020.

 

Scientific Name:   Nectria ocellata  Perrier, 1925

Common Name:   Spotted Sea Star

Pentagonaster duebeni

Photo by Paul Sorensen. South Australia, Rapid Bay, March 2022.

 

Scientific Name: Leiaster sp. 

Common Name: Velvety Sea Stars

Leiaster sp.

Photo by Paul Sorensen. Queensland, Lady Musgrave Island, October 2007.

 

Scientific Name: Linckia laevigata   (Linnaeus, 1758)

Common Name: Blue Linckia

Linckia laevigata

Photo by Paul Sorensen. Philippines, Dauin, September 2016.

 

 

SUBPHYLYUM: ECHINOZOA

CLASS: ECHINOIDEA

 

Scientific Name: Phyllacanthus irregulatis  (Mortensen, 1928)

Common Name: Club-spined Sea Urchin

Photo by Paul Sorensen. South Australia, Rapid Bay 2022.

 

 

SUBPHYLYUM: ECHINOZOA

CLASS: HOLOTHUROIDEA

 

Scientific Name: Australostichopus mollis   (Hutton, 1872)

Common Name: Australasian Brown Sea Cucumber

Australostichopus mollis
Photo by Paul Sorensen. Victoria, Blairgowrie Pier 2022. 
 

 

Scientific Name: Paracaudina bacillis   (O’Loughlin & Barmos, 2011)

Common Name: Sea Cucumber

Sea Cucumber, Paracaudina bacillis

Photo by Paul Sorensen. Victoria, Blairgowrie Pier 2021.

Paracaudina bacillis

Photo by Paul Sorensen. Victoria, Rye Pier 2017.