LARVAL DEVELOPMENT OF 3 ROUGHY SPECIES COMPLEXES (PISCES, TRACHICHTHYIDAE) FROM SOUTHERN AUSTRALIAN WATERS, WITH COMMENTS ON THE OCCURRENCEOF ORANGE ROUGHY HOPLOSTETHUS-ATLANTICUS

The larval development of three roughy species complexes, Paratrachich thys sp., Aulotrachichthys sp., and Optivus sp., is described and illu strated using larvae collected from Tasmanian and New South Wales wate rs. Larvae were identified using meristic and morphological characters and are characterized by differences in head and dermal spination, si ze at caudal flexion, and size and pigmentation of the pelvic fins. He ad spination is well developed in Aulotrachichthys, and weak in Optivu s and Paratrachichthys. Dermal spination is well developed in postflex ion Aulotrachichthys and flexion Optivus, but absent in Paratrachichth ys. Development of a luminous organ and anterior migration of the anus occur much earlier in Aulotrachichthys than Paratrachichthys and are notably absent in Optivus. The use of these larval characters in trach ichthyid systematics, and the possible reasons for the absence in our samples of larvae attributable to orange roughy Hoplostethus atlanticu s, are discussed.