First things first : sea slugs and sea cucumbers aren ’ thymine even in the same taxonomic group. Sea slugs are a marine gastropod, which is depart of Phylum Mollusca, where ocean cucumbers are separate of Phylum Echinodermata. To put it plainly, ocean slugs are more closely related to shelled animals, like clams and oysters, than they are to sea cucumbers. On the other hand, sea cucumbers are most close related to barbed animals, like ocean stars and sea urchins .
“ Sea slug ” is most normally used in reference to nudibranchs, which are often brightly-colored intricate gastropods found all over the world. There are approximately 3,000 sea slug species known to science, and we continue to discover fresh species today. The name can besides be used to describe sacoglossans, sea hares and ocean butterflies ( besides known as pteropods ). While all types of sea slugs have their unique qualities, they often resemble tellurian land slugs. The name “ sea cucumber ” refers to more than 1,000 species in the course Holothuroidea named for their cucumber-like appearance .
so, how can you tell these two namby-pamby critters apart ? The easiest way is to look at the promontory ( or rather, look if there is one ). Most sea slugs have a defined “ head ” with tentacles used to sense their surroundings. These tentacles, called rhinophores, allow sea slugs to “ smell ” chemical signals. Some sea slugs besides have exposed gills on their backs ( in fact, the term “ sea slug ” comes from greek and latin words meaning “ naked gills ” ), which can appear featherlike and brightly-colored. conversely, sea cucumbers have no definitive head end—they kind of search like subaqueous sausages. You can sometimes see tentacles coming out of one end that the cucumber uses to feed, but they can retract those back into their bodies.
If you take a closer look, you ’ ll be able to see bantam tube feet on the sea cucumbers that are absent from the ocean bullet. To move forward, the cucumber pushes water into the feet through a water vascular system, which makes the feet firm and allows them to act like bantam legs that creep the cucumber along. Sea slug miss tube feet and undulate along the ocean floor in a manner that looks alike to land slugs ( although some sea slugs can swim, excessively ) .
The two besides differ in their defense mechanisms—although this is not recommended as a room to test which is which ! Since both animals lack hard shells or spines to deter predators, they have evolved to possess some pretty creative ways of defending themselves. Sea slugs are often toxic and have bright coloring to warn predators not to mess with them. They can besides secrete acidic, ink or sludge ( depending on the species ). Although sea cucumbers can besides contain toxins, they have an extra weapon—when threatened, they can spew their internal organs out of their anus. so, if you see a long invertebrate with its organs expelled from their consistency, it ’ s a safe stake you ’ re looking at a ocean cucumber .
There you have it—everything you need to know to tell these eldritch and wilderness invertebrates apart. now whether you ’ re at trivium night, the aquarium or just looking for singular dinner conversations, you ’ ll be able to wow your friends and establish yourself as an invertebrate adept.
Read more: Jian Bing, Chinese Crepes (煎饼)
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