(plural branchiospinae) gill raker (one of a series of variously shaped bony or cartilaginous projections on the inner side of the branchial arch. The rakers have epithelial denticles and both their gross and fine structure serves to retain food particles in the mouth. The gill raker count normally includes all rakers, even the rudiments, and is made on the front half of the first arch. Upper and lower gill raker counts may be presented as the upper and the lower (including the central raker), e.g. 9 + 17; or as upper rakers, central raker, and lower rakers, e.g. 9 + 1 + 16. The most anterior and posterior rakers are often small and delicate, easily torn or lost if the arch is removed. Plankton feeders have numerous, crowded, elongate and fine rakers while predators have few, separated, short and stubby rakers)
Dictionary of ichthyology. 2009.