''Echinometra mathaei'', the burrowing urchin, is a
species of
sea urchin
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 . The spherical, hard shells (tests) of ...
in the
family Echinometridae
The Echinometridae are a family of sea urchins in the class Echinoidea.
Characteristics
All Echinometridae have imperforate tubercles and compound ambulacral plates.Indo-Pacific
The Indo-Pacific is a vast biogeographic region of Earth.
In a narrow sense, sometimes known as the Indo-West Pacific or Indo-Pacific Asia, it comprises the tropical waters of the Indian Ocean, the western and central Pacific Ocean, and the ...
region. The
type locality
Type locality may refer to:
* Type locality (biology)
* Type locality (geology)
See also
* Local (disambiguation)
* Locality (disambiguation)
{{disambiguation ...
is
Mauritius.
Description
''Echinometra mathaei'' grows to a
test 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, the East African coast and the Red Sea to Hawaii.[
]
Biology
''Echinometra mathaei'' uses its spines and teeth (part of the mouthparts known as Aristotle's lantern
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 . The spherical, hard shells (tests) of ...
) to dig itself into the basaltic and calcareous rock where it lives.[ It emerges from these hollows at night to graze on ]algae
Algae (; singular alga ) is an informal term for a large and diverse group of photosynthetic eukaryotic organisms. It is a polyphyletic grouping that includes species from multiple distinct clades. Included organisms range from unicellular mic ...
. As with other sea urchins, breeding involves releasing gametes into the water column. Fertilisation is external and the echinopluteus larvae are planktonic. When these settle on the seabed, they undergo metamorphosis
Metamorphosis is a biological process by which an animal physically develops including birth or hatching, involving a conspicuous and relatively abrupt change in the animal's body structure through cell growth and differentiation. Some inse ...
into juvenile sea urchins.bioerosion
Bioerosion describes the breakdown of hard ocean substrates – and less often terrestrial substrates – by living organisms. Marine bioerosion can be caused by mollusks, polychaete worms, phoronids, sponges, crustaceans, echinoids, and ...
of coral reefs. Its natural predators are mostly finfish
Fish are aquatic, craniate, gill-bearing animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% of liv ...
but there is also some predation by brittle stars 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 shrimp
Shrimp are crustaceans (a form of shellfish) with elongated bodies and a primarily swimming mode of locomotion – most commonly Caridea and Dendrobranchiata of the decapod order, although some crustaceans outside of this order are refer ...
, ''Athanas areteformi
''Athanas'' is a genus of shrimp of the family Alpheidae. These are small shrimp measuring 2 cm in length. Females have smaller chelae than males.
Some species, including ''A. djiboutensis'', are called "bulldozer shrimp" because of the ...
'', lives among the spines of this sea urchin [ and its appearance is ]mimicked
In evolutionary biology, mimicry is an evolved resemblance between an organism and another object, often an organism of another species. Mimicry may evolve between different species, or between individuals of the same species. Often, mimicry f ...
by the mantis shrimp
Mantis shrimp, or stomatopods, are carnivorous marine crustaceans of the order Stomatopoda (). Stomatopods branched off from other members of the class Malacostraca around 340 million years ago. Mantis shrimp typically grow to around in lengt ...
, '' Echinosquilla guerinii'', which conceals itself in a hole in the rock with only its spiny telson visible.[
Copper 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