pseudacanth

a false fin spine; a hard-ray; a spine-like ray which develops from a soft ray and acquires a stiff and pointed character. Pseudacanths are found in certain groups of fishes amongst the Malacopterygii which lack the spinous rays found in many Acanthopterygii, e.g. Notacanthidae, Cyprinus (Cyprinidae), Ictalurus (Ictaluridae)