Search for the Gobi Old Sister Group (Actinopterygii: Percomorpha)

Numerous fish groups have been proposed as the possible sister group of the Gobioidei. This paper attempts to identify selected putative autapomorphies for gobioids, and then documents cases of morphologically similar states that may be homologous to the gobioid condition in a broad variety of percomorph taxa. The taxon with the greatest number of such states is the scorpaeniform Hoplichthyidae, which shares 11 (of 23) putatively homologous apomorphies. However, hoplichthyids share other putative apomorphies with platycephalids in particular, and scorpaeniforms more generally, that are not found in gobioids. Other groups sharing several apparent apomorphies with gobioids are the gobiesocid/callionymoid lineage, and the trachinoids. Difficulties with each of the above scenarios are trenchant, and are explored.