''Sterechinus'' is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

sea urchin Sea urchins or urchins () are echinoderms in the class (biology), class Echinoidea. About 950 species live on the seabed, inhabiting all oceans and depth zones from the intertidal zone to deep seas of . They typically have a globular body cove ...

s in the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Echinidae Echinidae is a family of sea urchins in the order Camarodonta. Members of the family are found in the Atlantic Ocean and the Antarctic.fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserve ...

and was found in Europe.

Description

Members of the genus ''Sterechinus'' have compound

ambulacral Ambulacral is a term typically used in the context of anatomical parts of the phylum Echinodermata or class Asteroidea and Edrioasteroidea. Echinoderms can have ambulacral parts that include ossicles, plates, spines, and suckers. For example, sea ...

plates that are trigeminate (composed of three elements). These plates have a primary tubercle articulating with a spine on the middle element, a small secondary tubercle in the interambulacral groove on one side of it and 3 pairs of pores on the other. The tube feet are connected to these pores in the living animal and the pore pairs are arranged in a vertical arc. The sutures between the plates are deeply indented. The area of narrow plates around the mouth is small and the buccal notches are shallowly grooved.''Stirechinus'' Desor, 1856
The Natural History Museum. Retrieved 2012-01-09.

Species

The type species of this genus is '' Stirechinus scillae'' which was first described from a fossil by Pierre Desor in 1856. ''Stirechinus scillae'' lived from the

Late Miocene The Late Miocene (also known as Upper Miocene) is a sub-epoch of the Miocene epoch (geology), Epoch made up of two faunal stage, stages. The Tortonian and Messinian stages comprise the Late Miocene sub-epoch, which lasted from 11.63 Ma (million ye ...

to the

Plio-Pleistocene The Plio-Pleistocene is an informally described geological pseudo-period, which begins about 5 million years ago (Mya) and, drawing forward, combines the time ranges of the formally defined Pliocene and Pleistocene epochs—marking from about 5&n ...

and further fossils have since been found in France, Sicily and Malta. None of the fossilized urchins so far discovered had any apical plates. Since then, other members of the genus have been described, all from the waters around Antarctica. The World Register of Marine Species lists the following

extant Extant or Least-concern species, least concern is the opposite of the word extinct. It may refer to: * Extant hereditary titles * Extant literature, surviving literature, such as ''Beowulf'', the oldest extant manuscript written in English * Exta ...

species in the genus: *'' Sterechinus agassizii'' Mortensen, 1910 *'' Sterechinus antarcticus'' Koehler, 1901 *'' Sterechinus bernasconiae'' Larrain, 1975 *'' Sterechinus dentifer'' Koehler, 1926 *'' Sterechinus diadema'' (Studer, 1876) *'' Sterechinus neumayeri'' (Meissner, 1900)

References

Echinidae Echinoidea genera {{echinoidea-stub