Spatangoida

The heart urchins are members of the order Spatangoida of sea urchins. Their body are somewhat elongated ovals in form, and are distinguished by the mouth being placed towards one end of the animal, and the anus towards the other. As a result, unlike most other sea urchins, heart urchins are bilaterally symmetrical, and have a distinct anterior surface. The presence and position of the mouth and anus typically give members of this group the distinct "heart" shape from which they get their common name. Heart urchins have no feeding lantern, and often have petaloids sunk into grooves. They are a

species of echinoderm

Echinocardium is a genus of sea urchins of the family Loveniidae, known as heart urchins. The name is derived from the Greek ἐχῖνος (echinos, "hedgehog, urchin") and καρδία (kardia, "heart").

Brissidae is a family of echinoderms belonging to the order Spatangoida.

Hemiasteridae is a family of echinoderms belonging to the order Spatangoida.

Loveniidae is a family of heart urchins in the order Spatangoida.

Micraster is an extinct genus of echinoids from the Late Cretaceous to the early Eocene. Its remains have been found in Africa, Antarctica, Europe, and North America. Micraster was an infaunal echinoid living in a burrow below the sediment surface. The test is clearly bilateral and there is a deep anterior groove to take in water containing organic particles to the mouth. The tube feet keep a supply of nutrient-laden water moving into the burrow. The anus has a waste tube behind it.

Asterostomatidae is an extinct family of sea urchins belonging to the order Spatangoida.

Lovenia is a genus of sea urchin that is the sister taxon to Breynia and Echinocardium.

Maretia is a genus of heart urchins belonging to the family Spatangidae.

Aeropsidae is a family of echinoderms belonging to the order Spatangoida. It contains one extant genus. There are also eight extinct genera, most of which fall in the subfamily Corasterinae.

Pericosmidae is a family of echinoderms belonging to the order Spatangoida.

species of sea urchin

Prenasteridae is a family of echinoderms belonging to the order Spatangoida.

Micrasteridae is a family of echinoderms belonging to the order Spatangoida.

Maretiidae is a family of echinoderms belonging to the order Spatangoida.

species of echinoderm

Eurypatagidae is a family of echinoderms belonging to the order Spatangoida.

Macropneustidae is a family of echinoderms belonging to the order Spatangoida.

Palaeostomatidae is a family of echinoderms belonging to the order Spatangoida.

species of echinoderm

Paleopneustidae is a family of echinoderms belonging to the order Spatangoida.

species of echinoderm

Aeropsis is a genus of sea urchins in the family Aeropsidae.

species of echinoderm

species of echinoderm

Palaeotropidae is a family of echinoderms belonging to the order Spatangoida.

species of sea urchin

species of echinoderm

Spatagobrissus is a genus of echinoderms belonging to the family Maretiidae.

species of sea urchin

species of echinoderm

Eupatagidae is a family of echinoderms belonging to the order Spatangoida.

Toxasteridae is an extinct family of sea urchins.

species of echinoderm

species of echinoderm

species of echinoderm