Systematic Position and Relationships of the Percesocine Fishes

THE FISH FAMILIES Sphyraenidae, Mugilidae, and Atherinidae have been assigned to the percesocine fishes by all authors, and many would include only these (e.g., Berg, 1940: 368). Others have expanded the group in various ways (e.g., Boulenger, 1904: 636). Most commonly, however, such expansion has extended only to the family Polynemidae (e.g., Regan, 1912: 846) or, in recent years, to the polynemid and phallostethoid fishes (e.g., Myers, 1935: 6). Generally, the percesocine fish groups have been placed at the front of or just ahead of the order Perciformes. The major question in this regard is whether they represent derivatives of a percoid or of a pre-percoid stock. In the present investigation some attempt has • been made to determine the interrelationships and systematic position of the Sphyraenidae, Mugilidae, Atherinidae, and Polynemidae. For this purpose Hawaiian specimens of Sphyraena barracuda (Sphyraenidae), Mugil cephalus (Mugilidae), Pranesus insularum (Atherinidae), and Polydactylus sexfilis (Polynemidae) have been stained with alizarin and dissected. To base conclusions regarding families on such limited material is obviously a treacherous undertaking. However, the Sphyraenidae, Mugilidae, and Polynemidae are rather closely-knit families and it is assum~d that, for these, any species is fairly representative. For the Atherinidae the situation is ':Iuite different. Indeed, Jordan (1923: 177) splIt the Atherinidae as usually conceived into f?ur separate families. It is therefore highly possIble that the structures described for Pranesus would be quite different in atherinid genera such as Craterocephalus or Melanotaenia. No phallostethoid fishes have been available. However, a considerable literature exists on the anatomy of these forms (Regan, 1916; Bailey, 1936; Villadolid and Manacop, 1934; Aurich,