acantho-, acanth-, -acanth, -acanths, -acanthid, -acanthous

(Greek: used either as a prefix or as a suffix; pointed appendages; spine, spiny; thorn, thorny)

typacanthid (s) (noun), typacanthids (pl)
Concerning a lifeform that has a normal arrangement of spines: Opposed to autacanthids, starfishes are considered to be typacnthids with usual or typical needle-like structures.
xenacanth (s) (noun), xenacanths (pl)
An extinct fish of the genus Xenacanthus: Greg was so happy when he found some information regarding the xenacanth, which was cartilaginous and not living anymore.
xenacanthine (s) (noun) (no pl)
A fossil or fish of the classification of Xenacanthini: Sam was so happy to find a drawing of what a xenacanthine might have looked like although it had been extinct for a very long time.
xenacanthine (adjective) (not comparable)
Relating to the division of Xenancanthini: Xenacanthine fishes or fossils are those that have long been extinct.
zoacanthosis (s) (noun), zoacanthoses (pl)
Dermatitis due to a foreign body, such as a bristle or hair from an animal: Jane noticed a bad spot developing on her arm after gardening the day before, so she went to the doctor who diagnosed it as being a case of zoacanthosis and extracted the stinger which had penetrated into her skin, and gave her some medication to relieve and cure the injury.