Phylogenetic study on the genera Eulophias and Zoarchias (Zoarcoidei: Perciformes)

Abstract

Morphological and molecular phylogenetic studies of the suborder Zoarcoidei group have previously been undertaken, but the two genera Eulophias and Zoarchias still remain enigmatic. Therefore, phylogenetic positions of the genera Eulophias and Zoarchias were inferred by analyzing the osteological and molecular methods, and those results compared with 14 representing species of four families within the suborder Zoarcoidei. Osteological cladistics was analyzed using 45 characters, and molecular phylogenies were analyzed using mitochondrial DNA 16S rRNA and COI genes. With respect to the phylogenetic relationships based on the osteology, the genera Eulophias, Zoarchias and Zoarcoidei species were supported monophyly for the suborder level by five synapomorphies (Single pair nostril present, suborbital shelf on third infraorbital bone absent, basisphenoid absent, parhypural and lower hypural fused and dorsal and anal fins smoothly connected without notch at junction). The Eulophias and Zoarchias formed a single clade with the Stichaeidae but they were separated each other as well as from the family Stichaeidae by four synapomorphies (Supratemporal connected with supracleithrum posteriorly, projecting limb on posttemporal presented dorsally, third anal pterygiopore supported second anal fin ray and dorsal and anal fin soft rays unbranched) and two synapomorphies (Seven branchiostegal rays present and two epurals present) respectively. With respect to the phylogenetic relationships based on the mitochondrial DNA, the two genera and Zoarcoidei species were supported monophyly for the suborder level. The Eulophias occured at the most basal position and the Zoarchias was clustered with the family Neozoarcidae. They were separated from each other as well as from the families Stichaeidae and Zoarcidae. Considering the osteological and molecular phylogenies, present study suggests a new classification for the two genera: (1) Eulophias belongs to a new family named as the Eulophiidae; (2) Zoarchias belongs to the family Neozoarcidae rather than to Stichaeidae and Zoarcidae.