Abstract

The phylogenetic relationships of 11 stromateoid species (nine from the Family Centrolophidae and one each from the Nomeidae and Tetragonuridae) were examined by allozyme electrophoresis. Data from 30 loci were used for three phylogenetic analyses. Two phenetic trees were derived: a UPGMA tree derived from Nei's unbiased genetic distance, and a distance-Wagner tree based on modified Rogers' distances. A cladistic analysis, using maximum parsimony, was also carried out with loci as characters and alleles as unordered states.

The tree topology of all three analyses showed a high degree of similarity, which increased confidence in the phylogenetic interpretation and generally supported the classical taxonomic theory of centrolophid relationships. The 'hard-spined' centrolophid taxa, including Seriolella, Psenopsis, Schedophilus labyrinthicus and Hyperoglyphe, formed a stable group In all trees. Psenopsis was closely allied to Seriolella in all three analyses, which supports the view that this genus is derived from Seriolella. Centrolophus and Tubbia consistently diverged from the ancestral line of taxa near the base of the tree, so may have diverged from ancestral stock earlier than previously thought. The most striking departure from current taxonomic theory was the wide separation of Schedophilus labyrinthicus and Schedophilus huttoni, indicating that the genus Schedophilus is polyphyletic. A revision of the genus is needed and should include morphological and electrophoretic analyses of all Schedophilus species, with particular reference to the type species S. medusophagus.