A phylogenetic reassessment of the monophyletic status of the family Soleidae, with comments on the suborder Soleoidei (Pisces; Pleuronectiformes)

Abstract

This article presents the phylogenetic conclusions of an osteological study of species belonging to the subfamilies (Soleinae and Achirinae) of the dextral flatfish family Soleidae (Pieuronectiformes; Soleoidei). A cladistic analysis of the data revealed that the subfamilies, but not the family, are monophyletic. The Soleinae were found to be more closely related to the other soleoid family, the Cynoglossidae, than to the Achirinae. If we accept the principle that only monophyletic groups are to be admitted into Linnean classification, it is suggested that the two subfamilies be raised to the family level. The anatomical data led to the proposal (with caution) that the sister group of the achirid–soleid–cynoglossid lineage is the pleuronectid subfamily Samarinae. Consequently, it is suggested that the suborder Soleoidei be eliminated by incorporating its three families into the Pleuronectoidei which becomes monophyletic. Also, it is proposed that the Pleuronectid subfamilies (Pleuronectinae, Poecilopsettinae, Paralichthodinae, Rhombosoleinae, Samarinae) be raised to the family level. However, since the monophyletic status of these taxa is dubious (except for the Samarinae) any hypothesis including them must await a proper cladistic analysis of their intra- and inter-relationships.