''Clypeaster humilis'' 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 Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

Clypeasteridae 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. Genera The World Register of Marine Species list the following genera a ...

. This species was first

scientifically described A species description is a formal description of a newly discovered species, usually in the form of a scientific paper. Its purpose is to give a clear description of a new species of organism and explain how it differs from species that have be ...

in 1778 by the German biologist

Nathanael Gottfried Leske Nathanael Gottfried Leske (22 October 1751 in Muskau – 25 November 1786 in Marburg) was a German natural scientist and geologist. After his studies at ''Bergakademie'' of Freiberg in Saxony and the ''Franckeschen Stiftungen'' in Halle, Leske b ...

. It occurs in the tropical Indo-Pacific region.

Description

''Clypeaster humilis'' is a medium-sized species of sea biscuit, growing to a maximum length of . Its shape is pentagonal and it is slightly longer than it is broad. The margin is quite thick and the petaloid area is raised above the rest of the surface. The individual petals are closed and the petaloid area occupies less than half the width of the

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), ...

. The oral (under) surface is somewhat concave and the food grooves are long and deeply incised. The spines are short, with the primaries hardly exceeding the length of the secondaries. When living, this sea biscuit is greenish-grey or brownish, the petaloid area sometimes being darker brown; the bare test is yellowish or beige.

Distribution

This species is found in the western Indo-Pacific region, its range extending from 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''; T ...

and

Persian Gulf The Persian Gulf ( fa, خلیج فارس, translit=xalij-e fârs, lit=Gulf of Persis, Fars, ), sometimes called the ( ar, اَلْخَلِيْجُ ٱلْعَرَبِيُّ, Al-Khalīj al-ˁArabī), is a Mediterranean sea (oceanography), me ...

to Malaysia, New Caledonia and northern Australia. It is found on sandy seabeds at depths down to about .

References

{{Taxonbar, from=Q2293755 Animals described in 1778 Clypeaster