Comparative osteology, relationships, and systematics of fish of the genus Zoarces (Zoarcidae, Perciformes)

Abstract

Comparative-osteological investigation of all species of the genus Zoarces is made: Z. fedorovi, Z. andriashevi, Z. elongatus, Z. viviparus, Z. americanus, and Z. gillii. In the skeleton of hyoid arch in species of Zoarces, Lycozoarces, and Lycodes, paired bony elements are found, not described previously, identified as parurohyalia which may be synapomorphy of Zoarcidae. Differences between the Zoarces species are revealed by 56 external morphological and osteological characters. Cladistic analysis yielded one tree 135, Ci 0.57, Ri 0.54 long. Cladistic analysis confirms validity of a recently described species Z. fedorovi, which turned out to be the most generalized in the genus Zoarces, as well as the validity of Z. elongatus. The species Z. americanus and Z. gillii occupy a terminal position preventing their isolation to independent genera as was previously supposed, as this would lead to paraphyly of the genus Zoarces.