''Stomopneustes variolaris'', the black sea urchin or long-spined sea 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 ...
, the only one in its genus ''Stomopneustes'' and only species still alive in its family
Stomopneustidae
Stomopneustidae is a family of echinoderms belonging to the order Stomopneustoida
Stomopneustoida is an order of echinoderms belonging to the class Echinoidea
Sea urchins () are spiny, globular echinoderms in the class Echinoidea. About ...
. It is found throughout the tropical Indo-Pacific, with a patchy distribution.
Description
It is a rather big and strong regular sea urchin. The spines are robust and sharp, black with sometimes a blue-greenish tinge (depending on the light). They can be recognized thanks to the 5 grey sutures on the upper face, exhibiting distinctive zig-zag pattern. The oral face is clearer. The juveniles are clearer too (they can be black but also pale brown), and often show strikingly asymmetrical spines, due to their habit to use them for digging hiding holes in soft rocks.
Image:S. variolaris.jpg, The five zig-zag sutures are visible.
Image:Oursins.jpg, ''Stomopneustes variolaris'' in Réunion island (along with some ''Echinometra mathaei
''Echinometra mathaei'', the burrowing urchin, is a species of sea urchin in the family Echinometridae. It occurs in shallow waters in the Indo-Pacific region. The type locality is Mauritius.
Description
''Echinometra mathaei'' grows to a ...
'').
Image:Stomopneustes variolaris plage Jacques Tessier.jpg, ''idem''
Image:Stomopneustes variolaris Réunion loges.jpg, ''Stomopneustes variolaris'' burrowing in Réunion island
They can be confused with the
Diadematidae
The Diadematidae are a family of sea urchins. Their tests are either rigid or flexible and their spines are long and hollow.
* '' Astropyga'' Gray, 1825
**'' Astropyga radiata'' ( Leske, 1778), extant
**'' Astropyga pulvinata'' (Lamarck, 1816), ...
sea urchins which sho longer and more slender spines, with an anal papilla, or with ''
Echinometra mathaei
''Echinometra mathaei'', the burrowing urchin, is a species of sea urchin in the family Echinometridae. It occurs in shallow waters in the Indo-Pacific region. The type locality is Mauritius.
Description
''Echinometra mathaei'' grows to a ...
'', which also digs holes but is smaller, with shorter spines and never truly black.
Habitat and distribution
This species shows a remarkably patchy distribution though it can be pretty abundant where they are found. They can be encountered from the east African coast to the Philippines, on rock and damaged reefs, most often in shallow waters but never too close to wave action.
They are particularly abundant in Sri Lanka.
See also
*
References
Stomopneustoida
Monotypic echinoderm genera
{{echinoidea-stub