Identification of larval and juvenile Canadian Atlantic gadoids with comments on the systematics of gadid subfamilies

Abstract

An attempt to identify larvae and juveniles of Gaidropsarus led to a broader survey of gadoid morphology. Representative specimens of all gadoid families and all Canadian Atlantic gadid species were examined for selected morphological characters. The polarity of these character states was examined using a cladistic approach and led to the conclusion that the gadids are composed of three groups, recognized herein as subfamilies: Gadinae, Lotinae, and Phycinae. The most informative structure examined was the caudal skeleton, which showed three characters with an obvious primitive state in some gadids: presence of X and Y bones, 6 "primary" caudal fin rays, and low (<40) total caudal fin ray counts. Dorsal fin structure, which has been the basis of previous gadid systematic arrangements, is also shown to be informative, providing good evidence of relationship within gadines and phycines. The proposed groupings receive some additional support in the gross morphological similarity of their larvae.