This phylum consists of over 7,000 species (2016) called echinoderms. ¹ The adults are recognizable by their five-point symmetry and the most notably distinct trait which most echinoders have is their remarkable powers of regeneration of tissue, organs, limbs, and of asexual reproduction, and in some cases, complete regeneration from a single limb.

Echinodermata is also the largest phylum that has no freshwater or terrestrial (land-based) representatives. The most well-known echinoderms are members of class Asteroidea, which are the star fish or sea stars.

1,900 species

Includes: sea stars

Peripodida, sea daisies, 3 species

Brisingida, deep sea dwelling, 2 families, 17 genera, 111 species

Forcipulatida, sea stars, 3 families, 49 genera, 294 species

Spinulosida, sea stars, 1 family, 7 genera, 120 species

Notomyotida, sea stars, 1 family, 9 genera, 75 species

Paxillosida, sea stars, 8 families, 61 genera, 453 species

Valvatida, sea stars, 17 familise, 172 genera, 695 species

Velatida, sea stars, 5 families, 19 genera, 200 species

700 species

Includes: sea lilies or feather stars

Sub-Class: Articulata

Comatulida, feather stars, 24 families with 500 species

Cyrtocrinida, sea lilies, 3 families, 12 genera,

Hyocrinida, sea lilies, 1 family,

Isocrindia, sea lilies, 4 families, 3 genera, 12 species

940 species (?)

Includes: sea urchins and sand dollars

Cassiduloida, sea urchins, 3 families, 13 genera, 63 species

Spatangoida, heart urchins, 25 families, 156 genera, 869 species

Diademotoida, sea urchin, 2 families, 11 genera, 43 species

Echinothurioida, leather urchins, 3 families, 13 genera, 64 species

Pedinoida, sea urchins, 1 family, 1 genera, 13 species

Arbacioida, sea urchins, 3 family, 28 genera , 83 species

Echinoida, sea urchins, 1 families, 1 genus, 1 species

Phymosomatoida, sea urchins, 1 family, 1 genus, 1 species

Salenioida, sea urchins, 1 families, 3 genera,

Temnopleuroida, sea urchins, 2 families, 16 genera, 157 species

Clypeasteroida, sand dollars, 22 families, 105 genera, 658 species

Holectypoida, sea urchins, 2 genera,

1717 species

Includes: sea cucumbers

Apodida, sea cucumber, 3 families, 44 genera, 341 species

Dendrochirotida, sea cucumbers, 12 families, 137 genera, 796 species

Elasipodida, sea cucumbers, 5 families, 27 genera, 172 species

Holothuriida, sea cucumber, 2 families, 7 genera, 259 species

Molpadida, sea cucumbers, 3 families, 10 genera, 105 species

Persiculida, sea cucumbers, 3 families, 8 genera, 41 species

Synallactida, sea cucumber, 3 families, 25 genera, 135 species

2,000 species

Includes: brittle stars

Euryalida, basket stars, 3 families, 50 genera, 199 species

Ophiurida, brittle stars, 5 families, 65 genera, 496 species

Amphilepidida, brittle stars, 11 families, 82 genera, 978 species

Ophiacanthida, brittle stars, 11 families, 95 genera, 626 species

Ophioleucida, brittle stars, 2 families, 8 genera, 32 species

Ophioscolecida, brittle stars, 2 families, 19 genera, 66 species

EX Extinct

EW Extinct in the Wild

CR Critically Endangered

EN Endangered

VU Vulnerable

NT Near Threatened

CD Conservation Dependent

LC Least Concern

NL Not Listed

The class Crinoida includes the animals of the phylum Echinodermata, which are called the Feather Stars. These animals date back to the Paleozoic era.

This feather star has a diameter of about five inches when fully extended and has from eighteen to twenty jointed arms which can be coiled up when the animal is not feeding. The arms are attached to a cup shaped body (calyz). Each arm have feathery appendages called pinnules, which have rows of tube feet on both sides of a central ambulacral groove lined with cilia. Each cilium is a membrane bound organelle with the shape of a slender threadlike projection and extends from the surface of the tube feet.

The passion flower feather star is a filter feeder which catches planktons and other particles of organic material with the tube feet on the pinnules. These tube feet are covered with a sticky mucus that traps food particles, then rolls it into a ball before moving the food balls into the ambulacral groove where the cilia propel the stream of mucus towards the animal′s mouth.

Reefs and areas of rubble.

The Ptilometra australis is native to the coasts of southeastern Australia and is found on reefs, in estuaries and bays at depths down to about 360 feet.