postclavicle
/ˌpəʊs(t)ˈklavɪkl/Ichthyol.
noun
In most bony fishes: each of one or more bones forming the posterior part of the pectoral girdle, lying behind, and partly overlapped by, the cleithrum, and having a spine projecting downwards into the muscles of the body wall.
Origin
Late 19th century; earliest use found in Theodore Gill (1837–1914). From post- + clavicle.