Interrelationships of Fishes of the Order Stomiiformes

Abstract

The order Stomiiformes (Vertebrata: Actinopterygii) is composed of 417 of deep open ocean fishes, including some of the most abundant vertebrates on earth. The monophyly of the order is well established morphologically, but its phylogenetic position relative to other fishes is not certain. While the prevailing view is that Stomiiformes is the basal neoteleost taxon, sister to Eurypterygii, some authors have placed the group in a clade with the osmeroid and galaxioid fishes. Furthermore, the relationships within the Stomiiformes are poorly understood, and much of the existing classification is suspected not to reflect natural groups. Previous attempts to understand the relationships of stomiiform fishes have been complicated by the extensive morphological homoplasy within the group. The present study is based on DNA sequence data from the nuclear and mitochondrial genomes and examines the phylogenetic position of Stomiiformes as well as the relationships within the group. The phylogeny is reconstructed using the parsimony and maximum likelihood criteria, and via Bayesian inference. The relationships recovered via all three methods are similar. Stomiiformes is recovered in a clade with osmeroids and galaxioids, not as the basal neoteleost group. Furthermore, the relationships recovered within the group contradict much of the existing classification.