Osteological evidence for monophyly of the Leiognathidae (Teleostei: Acanthomorpha: Acanthuriformes)

Osteological characters supporting monophyly and identification of extant Leiognathidae are reviewed. Ten osteological synapomorphies support monophyly of the Leiognathidae, involving modification of the ribs, gill arches, palatoquadrate, median fins and branchiostegals. Fourteen additional characters are noted that nest the Leiognathidae within the Acanthuriformes (sensu Gill Leis). Nine further characters are noted as useful for identification of leiognathids, though each occurs more widely among acanthuriforms and other fishes. Three fossil genera that have been assigned to the Leiognathidae are briefly reviewed for the various leiognathid characters. Only one fossil genus, †Euleiognathus Yabumoto Uyeno, appears correctly placed in the family.