Larval development of the Common Ponyfish, Leiognathus equulus (Teleostei: Leiognathidae)

Larval development of <i>Leiognathus equulus</i> is described from reared postflexion specimens (4.6–15.8 mm Standard Length, SL) from Taiwan. Larvae have strong head spination, particularly a supraoccipital crest, strong supraocular ridge and very long, serrate preopercular spines, with the spine at the preopercular angle initially heavily pigmented. Fin spines are robust, and the anterior spines of dorsal, anal and pelvic fins are long and serrate. Structures characteristic of the family Leiognathidae form early in development (ca. 5 mm SL), including the very protrusible mouth, the fin-locking mechanism and the bacterial light organ. Pigment is initially largely confined to the ventral midline, but as development proceeds, extensive lateral and dorsal pigment patches appear. Larvae of <i>L. equulus</i> have the Trnski and Leis Morph 1 morphology.