Holothuroidea vs holothurian

Holothuroidea and holothurian both are nouns.

Word	Noun	Adjective	Verb	Adverb
Holothuroidea	Yes	No	No	No
holothurian	Yes	No	No	No

Holothuroidea (noun)	holothurian (noun)
class of echinoderms including the sea cucumbers	echinoderm having a flexible sausage-shaped body, tentacles surrounding the mouth and tube feet; free-living mud feeders