| Holectypoida Temporal range: | |
|---|---|
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| Echinoneus cyclostomus | |
| Scientific classification | |
| Kingdom: | |
| Phylum: | |
| Class: | |
| Superorder: | |
| Order: | Holectypoida Duncan, 1889 |
| Family: | Echinoneidae Agassiz, 1847 |
| Genera | |
The Holectypoida are an order of sea urchins related to the sand dollars. The order consists of just two living genera, but was once more diverse.
In appearance, the living holectypoids are similar to sand dollars, but with less flattened bodies and an oval outline. They also lack the petal-like patterns found on the bodies of sand dollars.
According to World Register of Marine Species :
Sea urchins are spiny, globular echinoderms in the class Echinoidea. About 950 species of sea urchin are distributed on the seabeds 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 covered in spines. Most urchin spines range in length from 3 to 10 cm, with outliers such as the black sea urchin possessing spines as long as 30 cm (12 in). 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, and humans.
A seashell or sea shell, also known simply as a shell, is a hard, protective outer layer usually created by an animal or organism that lives in the sea. The shell is part of the body of the animal. Empty seashells are often found washed up on beaches by beachcombers. The shells are empty because the animal has died and the soft parts have decomposed or been eaten by another animal.
Aleutians East Borough is a 2nd class borough in the U.S. state of Alaska. As of the 2020 census the borough's population was 3,420. The borough seat is Sand Point.
Alamosa County is a county located in the U.S. state of Colorado. As of the 2020 census, the population was 16,376. The county seat is Alamosa. The county name is the Spanish language word for a grove of cottonwood trees.
Destin is a city located in Okaloosa County, Florida, United States. It is a principal city of the Crestview–Fort Walton Beach–Destin metropolitan area.
Sand dollars are species of flat, burrowing sea urchins belonging to the order Clypeasteroida. Some species within the order, not quite as flat, are known as sea biscuits. Sand dollars can also be called "sand cakes" or "cake urchins".
The Lamniformes are an order of sharks commonly known as mackerel sharks. It includes some of the most familiar species of sharks, such as the great white, as well as more unusual representatives, such as the goblin shark and megamouth shark.
North Haven is a town in New Haven County, Connecticut on the outskirts of New Haven, Connecticut. The town is part of the South Central Connecticut Planning Region. As of the 2020 census, it had a population of 24,253.
The Hôtel Lambert is a hôtel particulier, a grand mansion townhouse, on the Quai Anjou on the eastern tip of the Île Saint-Louis, in the 4th arrondissement of Paris. In the 19th century, the name Hôtel Lambert also came to designate a political faction of Polish exiles associated with Prince Adam Jerzy Czartoryski, who had purchased the Hôtel Lambert.
Phyllis Barbara Lambert is a Canadian architect, philanthropist, and member of the Bronfman family.
Core plugs, also called freeze plugs or Welch plugs, are used to fill the sand casting core holes found on water-cooled internal combustion engines.
Cassiduloida is an order of sea urchins. The group was extremely diverse with many families and species during the Mesozoic, but today, only seven extant species remain.
The heart urchins or Spatangoida are an order of sea urchins.
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.
Dendraster excentricus, also known as the eccentric sand dollar, sea-cake, biscuit-urchin, western sand dollar, or Pacific sand dollar, is a species of sand dollar in the family Dendrasteridae. It is a flattened, burrowing sea urchin found in the north-eastern Pacific Ocean from Alaska to Baja California.
The dollar sunfish is a species of freshwater fish in the sunfish family of order Perciformes. It is categorized as a warm water pan-fish. Early settlers said that this species of sunfish resembled a European species they called bream. Historically it has been found along the Southern Atlantic coastal drainages from North Carolina to Florida, and west to Texas. Lepomis marginatus mainly feeds on detritus and filamentous algae as well as a few terrestrial insects. The juvenile and mature fish do not have many predators, but the eggs in the nest are in danger of predation from a few different species of fish.
Scutellidae is a family of sand dollars in the superfamily Scutellidea. All genera except Scaphechinus are extinct.
Irregularia is an extant infraclass of sea urchins that first appeared in the Lower Jurassic.
The Neognathostomata are a superorder of sea urchins.
Clypeasteridae is a family of sea urchins in the order Clypeasteroida. This family was first scientifically described in 1835 by the Swiss-American biologist Louis Agassiz.
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