Antiarcha
plural noun
An·ti·ar·cha
: a subclass or other division of Placodermi comprising small Devonian freshwater ostracoderms having complex bony armor on the anterior part of the body and a pair of pectoral appendages resembling paddles
Word History
Etymology
New Latin, from anti- entry 1 + -archa (from Greek archos anus); from the contrast in the location of the anus with that of the Urochordata