The species of this order are characterised by the presence of a bony suborbital stay. Although the order has generally been considered monophyletic, Imamura & Yabe (2002) proposed that the scorpaeniforms be divided into two (distantly related) monophyletic groups and suggested placing the two groups as suborders of the Perciformes. Until that study is fully evaluated we retain the order as a single group. The classification within the group has varied considerably. Washington et al. (1984) discussed relationships and Nelson (1994) recognised 24 families in seven suborders and, subsequently, assigned 25 families to seven suborders (Nelson 2006). Ishida (1994) discussed relationships within the suborder Scorpaenoidei and elevated a number of subfamilies to familial level. Nelson (2006) discussed the complexity of the group and summarised the various studies.
The main differences in the various classifications relate to the suborder Scorpaenoidei and, in particular, to the group traditionally recognised as the Family Scorpaenidae. Nelson (1994) divided the family into 11 subfamilies and, subsequently, into nine subfamilies (Nelson 2006). Poss (1999) generally followed the classification of Nelson (1994) and provided a discussion on the difficulties of defining the various groups. Here we generally follow the classification of Ishida (1994). Mandrytsa (2001) also discussed relationships.
The suborders are not used here because of difficulties in defining the monophyly of the Scorpaenoidei. Hiro Motomura, Bill Eschmeyer, Les Knapp and Stuart Poss kindly provided valuable information about the species in this order.
Imamura, H. & Yabe, M. 2002. Demise of the Scorpaeniformes (Actinopterygii: Percomorpha): an alternative phylogenetic hypothesis. Bulletin of Fisheries Sciences, Hokkaido University 53(3): 107-128
Ishida, M. 1994. Phylogeny of the suborder Scorpaenoidei (Pisces: Scorpaeniformes). Bulletin of Nansei National Fisheries Research Institute 27: 1-112
Mandrytsa, S.A. 2001. Lateral Line System and Classification of Scorpaenoid Fishes (Scorpeaniformes: Scorpaenidei). Perm : Perm State Univ. Press pp. 1-393.
Nelson, J.S. 1994. Fishes of the World. New York : John Wiley & Sons 600 pp.
Nelson, J.S. 2006. Fishes of the World. Hoboken, New Jersey : John Wiley & Sons, Inc. 601 pp.
Poss, S.G. 1999. Families Scorpaenidae, Caracanthidae, Aploactinidae. pp. 2291-2358 in Carpenter, K.E. & Niem, T.H. (eds). The Living Marine Resources of the Western Central Pacific. FAO Species Identification Guide for Fisheries Purposes. Rome : FAO Vol. 4 2069-2790 pp.
Washington, B.B., Eschmeyer, W.N. & Howe, K.M. 1984. Scorpaeniformes: relationships. 438-447 figs 240-241 in Moser, H.G. et al. (eds). Ontogeny and Systematics of Fishes. American Society of Ichthyologists and Herpetologists. Special Publication 1: 1-760