Larvae of five fish families with pattern 10 of the ramus lateralis accessorius nerve (Arripidae, Girellidae, Kyphosidae, Microcanthidae and Scorpididae) : Relevance to relationships

We describe the larvae of five temperate Australian fishes from five percoid families considered to form part of a monophyletic group because they share the uncommon pattern 10 of the facial nerve ramus lateralis accessorius (RLA-10). An attempt was made to assess to what extent the larval characters described for these species-Arripis trutta (Arripidae), Girella tricuspidata (Girellidae), Kyphosus sp. (Kyphosidae), Atypichthys strigatus (Microcanthidae) and Scorpis (lineolata?) (Scorpididae)-support a close relationship among these RLA-10 families. Larvae of the five species share similarities in body form, head spination, fin formation and pigment pattern, and generally fit the "distinctive larval form" previously described for "girelloid" RLA-10 families. Although such similarities are consistent with a close relationship among these families, most attributes of the distinctive larval form are also present in larvae of a number of non RLA-10 percoid families, notably the Pomatomidae. Based only on larval characters, one could hypothesize that most RLA-10 percoid families, including the Dichistiidae, form part of a larger group that also includes non RLA-10 families such as the Pomatomidae. Alternatively, the "distinctive larval form" in Pomatomus and some other non RLA-10 families could have been acquired independently. However, since we could not show that any of the attributes of the distinctive larval form constitute synapomorphies, nor is the sister group of the RLA-10 families known, neither of these alternatives could be tested during this study. Larval characters alone cannot at present resolve the relationships of the RLA-10 families.