''Eupentacta quinquesemita'' is a
species
A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...
of
sea cucumber
Sea cucumbers are echinoderms from the class (biology), class Holothuroidea ( ). They are benthic marine animals found on the sea floor worldwide, and the number of known holothuroid species worldwide is about 1,786, with the greatest number be ...
, a marine invertebrate with an elongated body, a leathery skin and tentacles surrounding the mouth. It is commonly known as the stiff-footed sea cucumber or white sea cucumber,
[ and occurs on rocky coasts in the northeastern Pacific Ocean.
]
Description
''Eupentacta quinquesemita'' can grow to a length of up to . The tube feet are arranged in four longitudinal rows; they are non-retractable and give the animal a spiny appearance. The skin between the tube feet is smooth, but both body wall and tube feet contain calcareous ossicles that make them stiff. The mouth is surrounded by ten branched feeding tentacle
In zoology, a tentacle is a flexible, mobile, and elongated organ present in some species of animals, most of them invertebrates. In animal anatomy, tentacles usually occur in one or more pairs. Anatomically, the tentacles of animals work main ...
s, the two lowest ones being smaller than the rest. The general body colour is white, the tentacles (often the only parts of the animal that are visible) being creamy-white, often with yellowish or pinkish bases. Bits of shell or other fragments often adhere to the tube feet.
Distribution and habitat
''E. quinquesemita'' is found in the northeastern Pacific Ocean, its range extending from Alaska to California.hydroids
Hydroids are a life stage for most animals of the class Hydrozoa, small predators related to jellyfish.
Some hydroids such as the freshwater '' Hydra'' are solitary, with the polyp attached directly to the substrate. When these produce buds, ...
and algae.
Ecology
A deposit and suspension feeder, ''E. quinquesemita'' uses its feeding tentacles to push material into its mouth, extracting the edible material and eliminating the unwanted debris. The larvae of a parasitic snail, '' Thyonicola americana'', enter in this way and develop into adults which invade the viscera while maintaining a connection to the gut lumen to release offspring. The sea cucumber is preyed on by several species of starfish, such as ''Solaster stimpsoni
''Solaster stimpsoni'', common names Stimpson's sun star, sun star, orange sun star, striped sunstar, and sun sea star, is a species of starfish in the family Solasteridae.
It was first described by Addison Emery Verrill in 1880.
Description
' ...
'', ''Pycnopodia helianthoides
''Pycnopodia helianthoides'', commonly known as the sunflower sea star, is a large starfish, sea star found in the northeastern Pacific Ocean. The only species of its genus, it is among the largest sea stars in the world, with a maximum arm span ...
'' and ''Leptasterias hexactis
''Leptasterias hexactis'' is a species of starfish in the Family (biology), family Asteriidae, commonly known as the six-rayed star. It is found in the intertidal zone of the western seaboard of the United States. It is a Predation, predator and ...
'', and fish such as the kelp greenling (''Hexagrammos decagrammus'').[
This sea cucumber exhibits a seasonal pattern of ]evisceration
Evisceration (pronunciation: /ɪvɪsəˈreɪʃən/) is disembowelment, i.e., the removal of viscera (internal organs, especially those in the abdominal cavity). The term may also refer to:
* Evisceration (autotomy), ejection of viscera as a defen ...
, expelling its guts in the autumn and growing a new set in the spring, resulting in a high proportion of ''T. americana'' parasites not completing their life cycle, but not all individuals do this.[
]
References
{{Taxonbar, from=Q2432938
Sclerodactylidae
Echinoderms described in 1867