''Echinometra mathaei'', the burrowing urchin, is a
species
In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...
of
sea urchin in the
family
Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...
Echinometridae. It occurs in shallow waters in the
Indo-Pacific region. The
type locality is
Mauritius
Mauritius ( ; french: Maurice, link=no ; mfe, label= Mauritian Creole, Moris ), officially the Republic of Mauritius, is an island nation in the Indian Ocean about off the southeast coast of the African continent, east of Madagascar. It ...
.
Description
''Echinometra mathaei'' grows to a
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), ...
diameter of about . The colour is quite variable but the test is usually a dark colour. The spines are sometimes green and purple with purple tips or entirely green with purple tips but this sea urchin can be distinguished from other species by a characteristic pale ring at the base of each spine.
Distribution
''Echinometra mathaei'' is found on reefs in tropical parts of the Indo-Pacific Ocean at depths down to . Its range extends from Madagascar
Madagascar (; mg, Madagasikara, ), officially the Republic of Madagascar ( mg, Repoblikan'i Madagasikara, links=no, ; french: République de Madagascar), is an island country in the Indian Ocean, approximately off the coast of East Africa ...
, the East African coast and the Red Sea
The Red Sea ( ar, البحر الأحمر - بحر القلزم, translit=Modern: al-Baḥr al-ʾAḥmar, Medieval: Baḥr al-Qulzum; or ; Coptic: ⲫⲓⲟⲙ ⲛ̀ϩⲁϩ ''Phiom Enhah'' or ⲫⲓⲟⲙ ⲛ̀ϣⲁⲣⲓ ''Phiom ǹšari''; ...
to Hawaii
Hawaii ( ; haw, Hawaii or ) is a state in the Western United States, located in the Pacific Ocean about from the U.S. mainland. It is the only U.S. state outside North America, the only state that is an archipelago, and the only state ...
.[
]
Biology
''Echinometra mathaei'' uses its spines and teeth (part of the mouthparts known as Aristotle's lantern) to dig itself into the basaltic and calcareous rock where it lives.[ It emerges from these hollows at night to graze on algae. As with other sea urchins, breeding involves releasing gametes into the water column. Fertilisation is external and the 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.
...
e are plankton
Plankton are the diverse collection of organisms found in water (or air) that are unable to propel themselves against a current (or wind). The individual organisms constituting plankton are called plankters. In the ocean, they provide a crucia ...
ic. When these settle on the seabed, they undergo metamorphosis into juvenile sea urchins.Gulf of Suez
The Gulf of Suez ( ar, خليج السويس, khalīǧ as-suwais; formerly , ', "Sea of Calm") is a gulf at the northern end of the Red Sea, to the west of the Sinai Peninsula. Situated to the east of the Sinai Peninsula is the smaller Gulf of ...
, in the most northerly part of its range, it spawns in the summer and autumn but in warmer waters, breeding takes place at any time of year.
Because of its burrowing activities, ''Echinometra mathaei'' causes bioerosion of coral reef
A coral reef is an underwater ecosystem characterized by reef-building corals. Reefs are formed of colonies of coral polyps held together by calcium carbonate. Most coral reefs are built from stony corals, whose polyps cluster in groups.
C ...
s. Its natural predators
Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill th ...
are mostly finfish but there is also some predation by brittle star
Brittle stars, serpent stars, or ophiuroids (; ; referring to the serpent-like arms of the brittle star) are echinoderms in the class Ophiuroidea, closely related to starfish. They crawl across the sea floor using their flexible arms for locomot ...
s and gastropod molluscs. It has been found that in areas where heavy fishing takes place, the number of urchins is increased because their natural predators are less abundant and as a consequence, greater damage to the reef takes place.
A commensal
Commensalism is a long-term biological interaction (symbiosis) in which members of one species gain benefits while those of the other species neither benefit nor are harmed. This is in contrast with mutualism, in which both organisms benefit fro ...
shrimp, '' Athanas areteformi'', lives among the spines of this sea urchin [ and its appearance is mimicked by the mantis shrimp, '' Echinosquilla guerinii'', which conceals itself in a hole in the rock with only its spiny ]telson
The telson () is the posterior-most division of the body of an arthropod. Depending on the definition, the telson is either considered to be the final segment of the arthropod body, or an additional division that is not a true segment on accou ...
visible.[
]Copper
Copper is a chemical element with the symbol Cu (from la, cuprum) and atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. A freshly exposed surface of pure copper has a pinkis ...
is having a detrimental effect to larvae at 0.02 mg/L, and adults have 48- and 96-h TL50 values of 0.54 and 0.30 mg/L. Fertilization success was also reduced to 50% in 0.18 mg/L, and cleavage of the 8-cell stage as well, at 0.42 mg/L of Cu++.
References
External links
*
{{Taxonbar, from=Q260571
Echinometridae
Animals described in 1825