398 



ONTOGENY AND SYSTEMATICS OF FISHES-AHLSTROM SYMPOSIUM 



acters found among percoids. The possession of normal abdom- 

 inal parapophyses, lack of ventral ridge scales or bucklers, and 

 a percoid type of caudal skeleton suggest to Rosen that caproids 

 appear to fit the present definition of a perciform while other 

 zeoids do not. 



These findings support the movement of the Caproidae higher 

 in Acanthopterygian classification. The very different larvae of 

 the two caproid genera suggest that a thorough reexamination 

 of the osteology of adult representatives of these genera could 

 be necessary before the family is placed somewhere else. 



There has been no phylogenetic systematic study of the order 

 Zeiformes. Inclusion of early life history characters would prob- 

 ably be useful in such a study, but these are unknown for most 

 members of the order. 



group. Rosen has suggested that the Zeiformes do not represent 

 a monophyletic lineage, but are best included within the Te- 

 traodontiformes with which they are united by seven synapo- 

 morphies. Within Rosen's classification, the Caproidae are the 

 sister group to the rest of the Tetraodontiformes. In addition, 

 the rest of the zeiform families are united with the plectognath 

 fishes by four synapomorphies while the plectognath families 

 are monophyletic on the basis of six synapomorphies. Evidence 

 from early life history characters supporting this classification 

 is very limited due to the lack of knowledge of the early life 

 history of most of these fishes, but the similarity in morphology 

 and pigmentation between newly hatched Zens faher larvae and 

 tetraodontid larvae does provide some support for Rosen's hy- 

 pothesis. 



Addendum: After this paper went to press. Rosen (1984) pub- 

 lished a phylogenetic analysis of the families (except Macru- 

 rocyttidae) herein included in the order Zeiformes which re- 

 sulted in a drastic change in the systematic placement of this 



Division of Fishes, National Museum of Natural History, 

 Smithsonian Institution, Washington, District of 

 Columbia 20560. 



Gasterosteiformes: Development and Relationships 

 R. A. Fritzsche 



THE actinopterygian fish order Gasterosteiformes contains a 

 diverse assemblage of specialized fishes. There are about 

 220 species arranged into 10 or II families (Fritzsche. 1982). 

 Historically this group has been divided into two or three orders, 

 under such names as Lophobranchii, Thoracostei, Solenich- 

 thyes, Catosteomi, Hemibranchii, Hypostomides, Gasterostei- 

 formes, Syngnathiformes, and Pegasiformes (Boulenger, 1904; 

 Berg, 1940; and Starks, 1902). Pietsch (1978b) presented infor- 

 mation which suggests that Pegasiformes are intermediate be- 

 tween the Gasterosteiformes and Syngnathiformes. Pegasids are 

 intermediate in (1) snout development and in the condition of 

 the nasal bones; (2) retention of the parietals; (3) retention of 

 three circumorbital bones; (4) presence of a dorsal strut join- 

 ing the ceratohyal and epihyal; (5) reduction in number of ele- 

 ments of the branchial arches; (6) the presence of two pairs of 

 pleural ribs; and (7) retention of support for a spinous dorsal 

 fin (Pietsch, 1978b). He proposed a tentative classification unit- 

 ing all three groups into the single order Gasterosteiformes. This 

 order is characterized by (1) branchiostegal rays reduced to 1- 

 5; (2) absence of supramaxillary, orbitosphenoid, and basi- 

 sphenoid; (3) postcleithrum reduced to single bone or absent; 

 (4) pelvic girdle never attached directly to cleithra; (5) rather 

 small mouth, often at end of more or less tubular snout; and 

 (6) armor of dermal plates covers most members (Fritzsche, 

 1982). Pegasids form the primitive sister-group of the Soleno- 

 stomidae and Syngnathidae. These families share a number of 

 derived character states including (1) feeding mechanism; (2) 

 metapterygoid absent; (3) hyoid apparatus short, bearing elon- 

 gate, filamentous branchiostegal rays; (4) gill opening restricted 

 to a small hole on the dorsolateral surface behind head; (5) gill 

 filaments tufted or lobe-like; (6) articular processes of mobile 

 vertebral centra absent; (7) posttemporal co-ossified with cra- 

 nium; (8) postcleithrum absent; and (9) head and trunk encased 

 by bony plates, tail encircled by bony rings (Pietsch, 1978b). 

 The Pegasidae, Solenostomidae and Syngnathidae form the 

 primitive sister-group of the Macrorhamphosidae, Centriscidae, 



Aulostomidae, and Fistulariidae and the resulting classification 

 is as follows: 



Order Gasterosteiformes 

 Suborder Gasterosteoidei 



Superfamily Aulorhynchoidea 

 Family Aulorhynchidae 



B 



Fig. 214. Eggs of some gasterosteiforms; (A) Gasterosleus acuteatus 

 (from Kuntz and RadclifTe, 1917); (B) Fistularta pelimha (from Mito, 

 1 96 1 a); (C) Macrorhamphosus scolopa.x (horn Hardy, 1 978a, after Spar- 

 ta, 1936); (D) l/ippocumpus ereclus (from Hardy, 1978a). 



