Echinarachnius parma, the common sand dollar, is a species of sand dollar native to the Northern Hemisphere.
The Diadematidae are a family of sea urchins. Their tests are either rigid or flexible and their spines are long and hollow.
Lytechinus variegatus, commonly called the green sea urchin or the variegated sea urchin, is a species of sea urchin that can be found in the warm waters of the western Atlantic Ocean and Caribbean Sea.
Eucidaris tribuloides, the slate pencil urchin, is a species of cidaroid sea urchins that inhabits littoral regions of the Atlantic Ocean. As a member of the basal echinoid order Cidaroida, its morphological, developmental and molecular genetic characteristics make it a phylogenetically interesting species.
Cidaroida is an order of primitive sea urchins, the only living order of the subclass Perischoechinoidea. All other orders of this subclass, which were even more primitive than the living forms, became extinct during the Mesozoic.
Echinarachnius is a genus of sand dollars, belonging to the family Echinarachniidae.
Cidaridae is a family of sea urchins in the order Cidaroida.
Toxopneustes pileolus, commonly known as the flower urchin, is a widespread and commonly encountered species of sea urchin from the Indo-West Pacific. It is considered highly dangerous, as it is capable of delivering extremely painful and medically significant stings when touched. It inhabits coral reefs, seagrass beds, and rocky or sandy environments at depths of up to 90 m (295 ft). It feeds on algae, bryozoans, and organic detritus.
Sphaerechinus granularis is a species of sea urchin in the family Toxopneustidae, commonly known as the violet sea urchin, or sometimes the purple sea urchin. Its range includes the Mediterranean Sea and eastern Atlantic Ocean.
Echinidae is a family of sea urchins in the order Echinoida. Members of the family are found in the Atlantic Ocean and the Antarctic.
Holasteroida is an order of irregular sea urchins.
Toxopneustes is a genus of sea urchins from the tropical Indo-Pacific. It contains four species. They are known to possess medically significant venom to humans on their pedicellariae. They are sometimes collectively known as flower urchins, after the most widespread and most commonly encountered species in the genus, the flower urchin. Species included in the genus are the following:
Eucidaris metularia, the ten-lined urchin, is a species of sea urchins in the family Cidaridae. It is found in shallow parts of the Indo-Pacific Ocean and is characterised by its sparse covering of banded, flat-tipped spines.
Eucidaris thouarsii, the slate pencil urchin, is a species of cidaroid sea urchins that inhabits littoral regions of the East Pacific Ocean.
Sabinella troglodytes is a species of small sea snail, a marine gastropod mollusk in the family Eulimidae. It is a parasitic snail found near the coast of Brazil which lives on the body of the slate pencil urchin Eucidaris tribuloides.
Dermechinus is a genus of sea urchin in the family Echinidae found in deep water in the southern Indian, Pacific and Atlantic Oceans. It is monotypic, with Dermechinus horridus, sometimes called the cactus urchin, being the only species.
Parechinus angulosus, the Cape urchin, is a sea urchin in the family Parechinidae endemic to southern Africa.
Goniocidaris is a genus of sea urchins (Echinoidea) in the family Cidaridae and typical of the subfamily Goniocidarinae. Extant species are mostly found in Indo-Pacific seas, often living at depth.
Eucidaris galapagensis, commonly referred to as the Slate Pencil Sea Urchin, is a species of echinoderms in the family of Cidaroid. This sea urchin lives in coastal areas in the Galapagos, Clipperton, and Cocos. The preferred substrate of these organisms is rocky, benthic environments that provide refuge. In fact, greater abundance of Slate Pencil Sea Urchins is correlated with correct substrate, as well as greater food availability. Their diet is primarily herbivorous, however, they also consume various invertebrates. They graze heavily on live corals and algae in open, shallow reef habitats. Their grazing schedule is not restricted to sunlight availability, and will graze nocturnally. Their diversity in diet is a result of their metabolism, as they are capable of remarkably efficient assimilation of nutrients. Pencil Slate Sea Urchin's crawl omnidirectionally in their environment. Additionally, they are able to sense surrounding light by photoreceptor cells that act as their visual system.
