Stages of Development of the Goosefish, Lophius americanus, and Comments on the Phylogenetic Significance of the Development of the Luring Apparatus in Lophiiformes

Abstract

The first developmental scheme for the anglerfish Lophius americanus is described. The stages of embryonic and larval development are based on 'defining characters'; other aspects of development are described as 'concurrent characters' (in the sense of Shardo 1995). The embryo phase is described in stages 1–16; the yolk-sac larva phase is described in stages 17–21; the feeding larva phase is described in stages 22–26. Stages 9–23 are defined by specimens from a developmental series collected by the author; the remaining stages are defined through analysis of museum specimens and descriptions from previous literature. The developmental stages of L. americanus are compared to those of the frogfish Antennarius striatus (Antennariidae: Lophiiformes), the only other anglerfish for which there are published stages. Landmarks in the development of the two species are used as a basis for comparative study. Two new putative synapomorphies for Lophiiformes, based on the development of the spinous dorsal fin, are proposed: (1) the pterygiophores of the spinous dorsal fin develop from a single condensation of tissue that later divides or separates into independent pterygiophores; and (2) the first pterygiophore supports both the first (the luring apparatus) and second dorsal fin spines. This results from a lack of division of the anteriormost pterygiophore in development. These characters are supported by evidence from the literature but require further study in more lophiiforms.