An echinoderm is any member of the phylum Echinodermata. The adults are recognisable by their radial symmetry, and include starfish, brittle stars, sea urchins, sand dollars, and sea cucumbers, as well as the sea lilies or "stone lilies". Adult echinoderms are found on the sea bed at every ocean depth, from the intertidal zone to the abyssal zone. The phylum contains about 7,000 living species, making it the second-largest grouping of deuterostomes, after the chordates. Echinoderms are the largest entirely marine phylum. The first definitive echinoderms appeared near the start of the Cambrian.
Sea urchins are spiny, globular echinoderms in the class Echinoidea. About 950 species of sea urchin live on the seabed of every ocean and inhabit every depth zone — from the intertidal seashore down to 5,000 meters. The spherical, hard shells (tests) of sea urchins are round and spiny, ranging in diameter from 3 to 10 cm. Sea urchins move slowly, crawling with tube feet, and also propel themselves with their spines. Although algae are the primary diet, sea urchins also eat slow-moving (sessile) animals. Predators that eat sea urchins include a wide variety of fish, starfish, crabs, marine mammals. Sea urchins are also used as food especially in Japan.
Fritillaria imperialis, the crown imperial, imperial fritillary or Kaiser's crown, is a species of flowering plant in the lily family Liliaceae, native to a wide stretch from the Anatolian plateau of Turkey, Iraq and Iran to Afghanistan, Pakistan, Northern India and the Himalayan foothills. It is also widely cultivated as an ornamental and reportedly naturalized in Austria, Sicily, and Washington State, USA. The common names and also the epithet "imperialis", literally "of the emperor", refer to the large circle of golden flowers, reminiscent of an emperor's crown.
The imperial woodpecker is a woodpecker species endemic to Mexico. If it is not extinct, it is the world's largest woodpecker species, at 56–60 cm (22–23.5 in) long. Researchers have discovered that the imperial woodpecker has slow climbing strides and a fast wing-flap rate compared with other woodpeckers. Owing to its close taxonomic relationship, and its similarity in appearance, to the ivory-billed woodpecker, it is sometimes called the Mexican ivory-billed woodpecker, but this name is also used for the extant pale-billed woodpecker. The large and conspicuous bird has long been known to the native inhabitants of Mexico and was called cuauhtotomomi in Nahuatl, uagam by the Tepehuán and cumecócari by the Tarahumara.
Eacles imperialis, the imperial moth, is a Nearctic member of the family Saturniidae and subfamily Ceratocampinae. The species was first described by Dru Drury in 1773.
The imperial pheasant is a gallopheasant from Southeast Asia. Long thought to be an enigmatic and elusive species, it is actually a cross of Edwards's pheasant and the silver pheasant, a hybrid.
The imperial amazon or Dominican amazon, also known as the sisserou, is a parrot found only on the Caribbean island of Dominica. It has been designated as the national bird of Dominica. The species is critically endangered. In 2019, it was estimated there were only about 50 mature individuals left in the wild.
In biology, a test is the hard shell of some spherical marine animals, notably sea urchins and microorganisms such as testate foraminiferans, radiolarians, and testate amoebae. The term is also applied to the covering of scale insects. The related Latin term testa is used for the hard seed coat of plant seeds.
The imperial cave salamander, imperial salamander, odorous cave salamander, or scented cave salamander is a species of salamander in the family Plethodontidae. It is endemic to Sardinia.
Strongylocentrotus droebachiensis is commonly known as the green sea urchin because of its characteristic green color. It is commonly found in northern waters all around the world including both the Pacific and Atlantic Oceans to a northerly latitude of 81 degrees and as far south as Maine and England. The average adult size is around 50 mm (2 in), but it has been recorded at a diameter of 87 mm (3.4 in). The green sea urchin prefers to eat seaweeds but will eat other organisms. They are eaten by a variety of predators, including sea stars, crabs, large fish, mammals, birds, and humans. The species name "droebachiensis" is derived from the name of the town Drøbak in Norway.
Heterocentrotus mamillatus, commonly known as the slate pencil urchin, red slate pencil urchin, or red pencil urchin, is a species of tropical sea urchin from the Indo-Pacific region.
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.
Strigatella imperialis is a species of sea snail, a marine gastropod mollusk in the family Mitridae, the miters or miter snails.
Cymbiola imperialis, the imperial volute, is a species of sea snail, a marine gastropod mollusk of the genus Cymbiola in the family Volutidae, the volutes.
Cidaridae is a family of sea urchins in the order Cidaroida.
The family Homolidae, known as carrier crabs or porter crabs, contains 14 genera of marine crabs. They mostly live on the continental slope and continental shelf, and are rarely encountered. Members of the Homolidae have their fifth pereiopods in a sub-dorsal position, which allows them to hold objects in place over the rear half of the carapace. The objects carried include sponges, black corals and gorgonians, and this behaviour may be a defence mechanism against predators. Some species have been observed carrying living sea urchins in a symbiotic relationship which allows them to benefit from the protection of the urchin's dangerous spikes.
The exquisite urchin is a sea urchin species found off the coast of the island of New Caledonia in the Pacific Ocean. It is an epifaunal deepwater species living at depths between 240 and 520 m and was only identified and named in 2006.
Heterocentrotus is a genus of slate pencil urchins, part of the familia Echinometridae.
Stylocidaris affinis, also known as pencil urchin or red lance urchin, is a species of sea urchin.
