os branchiostegale

(plural ossa branchiostegalia))

branchiostegal (one of the dermal bony (or cartilaginous) struts inserting on the epihyal and/or ceratohyal and sometimes the interhyal and hypohyal, and supporting the branchiostegal membranes. Of various forms from narrow, to plate-like to hooked, with numbers varying according to phylogeny, up to 50 in Actinopterygii to none in Crossopterygii. Less preferably called branchiostegal rays because of confusion with the fin rays)