. Bulletin of the Natural History Museum Zoology. 134 MOOI AND AC. GILL. Fig. 16 Type 1 epaxial musculature in Pseudanthias taeniatus (USNM 279782, mm SL). A separate slip of the epaxial inserts on to the first to fourth dorsal-fin pterygiophore, and epaxial insertions occur as far posteriorly as the eighth pterygiophore. Abbreviations and other methods of presentation as in Figs 1,3. Scale bar = 5 mm. tions, an argument could be made for homology with a Type 2 morphology found among the perciforms, and implied relationships should be investigated. Optimizing epaxial char- acter dist
. Bulletin of the Natural History Museum Zoology. 134 MOOI AND AC. GILL. Fig. 16 Type 1 epaxial musculature in Pseudanthias taeniatus (USNM 279782, mm SL). A separate slip of the epaxial inserts on to the first to fourth dorsal-fin pterygiophore, and epaxial insertions occur as far posteriorly as the eighth pterygiophore. Abbreviations and other methods of presentation as in Figs 1,3. Scale bar = 5 mm. tions, an argument could be made for homology with a Type 2 morphology found among the perciforms, and implied relationships should be investigated. Optimizing epaxial char- acter distribution on existing phytogenies of the tetraodonti- forms (Winterbottom, 1974b; Leis, 1984) implies that the Type 2 morphology is the primitive condition for the order. Unfortunately, the character does not provide additional evidence for intrarelationships because the remaining extant families of tetraodontiforms do not possess a spinous dorsal fin. Even among taxa that do not exhibit epaxial insertions on to the distal portions of the proximal-middle pterygiophores or on to the distal radials, we did observe some possibly significant variation in other muscle morphology. As noted above, most (if not all) acanthomorphs have epaxial muscle insertions on to the proximal ends or along the shafts of the dorsal-fin pterygiophores. In most pleuronectiforms the epaxial muscle inserts via bundles of muscle fibres that pass underneath the depressores dorsales. Psettodes, usually con- sidered the sister group of other pleuronectiforms, has the epaxial muscles overlying most of the length of the pterygio- phores, with very short connections extending under the depressors to the pterygiophore shafts just ventral to the spine articulations. These connections only occur on the first 12 pterygiophores. Psettodes is the only genus with dorsal-fin spines; all other flatfishes have epaxial insertions on to a higher number of pterygiophores, although most of the examined taxa have dorsal fins e
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