Both Anisacanthus and Holodiscus are what level of classification?
Anisacanthus Anisacanthus is a genus of flowering plants in the bear's breeches family, Acanthaceae. The generic name is derived from the Greek words ανισος ("anisos"), meaning "unequal," and ακανθος ("acanthos"), meaning "thorn." Members of the genus are native to tropical and subtropical regions of the Americas. They are commonly known as desert honeysuckles, though this term is shared with the genus "Ancistranthus", and is something of a misnomer as true honeysuckles (genus "Lonicera") belong to the family Caprifoliaceae. "Anisacanthus" species are sometimes cultivated for use in xeriscaping.
Ptyctodontida The ptyctodontids ("folded-teeth") are placoderms of the order Ptyctodontida, containing the family Ptyctodontidae. With their big heads, big eyes, reduced armor and long bodies, the ptyctodontids bore a superficial resemblance to modern day chimaeras (Holocephali). Their armor was reduced to a pattern of small plates around the head and neck. Like the extinct and related acanthothoracids, and the living and unrelated holocephalians, most of the ptyctodontids are thought to have lived near the sea bottom and preyed on shellfish.