''Echinus tylodes'' is a species of sea urchin in the Echinidae family. It is white with rather sparse pink spines, and is

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...

to the eastern coast of North America including the

Gulf of Mexico The Gulf of Mexico ( es, Golfo de México) is an oceanic basin, ocean basin and a marginal sea of the Atlantic Ocean, largely surrounded by the North American continent. It is bounded on the northeast, north and northwest by the Gulf Coast of ...

Description

''Echinus tylodes'' has a subglobular

test Test(s), testing, or TEST may refer to: * Test (assessment), an educational assessment intended to measure the respondents' knowledge or other abilities Arts and entertainment * ''Test'' (2013 film), an American film * ''Test'' (2014 film), ...

about two-thirds as high as it is wide and grows to a diameter of . The joints between the ambulacral plates and the pores through which the tube feet project are both sunken below the general surface of the test. The tubercles to which the primary spines are attached are slightly raised, making it appear as if they are on vertical ridges. The primary spines are short and stout, and the test is easily visible as few secondary spines occur. The general colour of this urchin is white and it has pink spines.

Distribution and habitat

''Echinus tylodes'' is found on the East Coast of the United States from

Cape Cod Cape Cod is a peninsula extending into the Atlantic Ocean from the southeastern corner of mainland Massachusetts, in the northeastern United States. Its historic, maritime character and ample beaches attract heavy tourism during the summer mont ...

southwards to the

Straits of Florida The Straits of Florida, Florida Straits, or Florida Strait ( es, Estrecho de Florida) is a strait located south-southeast of the North American mainland, generally accepted to be between the Gulf of Mexico and the Atlantic Ocean, and between th ...

and in the Gulf of Mexico. It is a deepwater species, being found at depths of . It is often found around deepwater

coral Corals are marine invertebrates within the class Anthozoa of the phylum Cnidaria. They typically form compact colonies of many identical individual polyps. Coral species include the important reef builders that inhabit tropical oceans and sec ...

s, sitting on the coral branches or around coral mounds among the remains of dead corals.

Biology

Most deepwater echinoderms feed on algal debris and

detritus In biology, detritus () is dead particulate organic material, as distinguished from dissolved organic material. Detritus typically includes the bodies or fragments of bodies of dead organisms, and fecal material. Detritus typically hosts commun ...

. Examination of the gut contents of this species also showed small shells and the skeletons of

hydroids Hydroids are a life stage for most animals of the class Hydrozoa, small predators related to jellyfish. Some hydroids such as the freshwater '' Hydra'' are solitary, with the polyp attached directly to the substrate. When these produce buds ...

. The eggs are small, which implies this species has echinopluteus

larva A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle. The ...

e which are

plankton Plankton are the diverse collection of organisms found in Hydrosphere, water (or atmosphere, air) that are unable to propel themselves against a Ocean current, current (or wind). The individual organisms constituting plankton are called plankt ...

ic.

Ecology

A deepwater video survey of the seabed over the Cape Fear coral mound off North Carolina found the sea urchins ''E. tylodes'' and the rather similar '' Echinus gracilis'' associated with squat lobsters ('' Eumunida picta'') and spider crabs ('' Rochinia crassa''). These were living among the living and dead remains of the coldwater coral (''

Lophelia pertusa ''Lophelia pertusa'', the only species in the genus ''Lophelia'', is a cold-water coral that grows in the deep waters throughout the North Atlantic ocean, as well as parts of the Caribbean Sea and Alboran Sea. Although ''L. pertusa'' reefs are ...

'') from which the mound was largely formed. Other

invertebrate Invertebrates are a paraphyletic group of animals that neither possess nor develop a vertebral column (commonly known as a ''backbone'' or ''spine''), derived from the notochord. This is a grouping including all animals apart from the chordate ...

s present included the deepwater starfish ('' Novodinia antillensis'') and the flytrap anemone ('' Actinoscyphia saginata''). The commonest fish species were the alfonsino (''

Beryx decadactylus The alfonsino (''Beryx decadactylus''), also known as the alfonsin, longfinned beryx, red bream, or imperador, is a species of deepwater berycid fish of the order Beryciformes. It can be found in temperate and subtropical ocean waters nearly wo ...

''), codlings ('' Laemonema'' spp.) and the conger eel (''

Conger oceanicus The American conger (''Conger oceanicus'') is a species of eel in the family Congridae. Other common names for this fish include conger, dog eel, poison eel and sea eel. It is a marine fish with a widespread distribution in the Western Atlantic f ...

'').

References

{{Taxonbar, from=Q2914132 tylodes Animals described in 1912 Taxa named by Hubert Lyman Clark