© 2004 by The Society for Integrative and Comparative Biology
Phylogeny and Jaw Ontogeny of Beloniform Fishes1
1 Department of Zoology, University of Manitoba, Z320 Duff Roblin Building, Winnipeg, MB, R3T 2N2, Canada
2 National Marine Fisheries Service Systematics Laboratory, Smithsonian Institution, P.O. Box 37012, NMNH Rm. WC-57, MRC 0153, Washington, D.C. 20013-7012
To investigate jaw evolution in beloniform fishes, we reconstructed the phylogeny of 54 species using fragments of two nuclear (RAG2 and Tmo-4C4) and two mitochondrial (cytochrome b and 16S rRNA) genes. Our total molecular evidence topology refutes the monophyly of needlefishes (Belonidae) and halfbeaks (Hemiramphidae), but supports the monophyly of flyingfishes (Exocoetidae) and sauries (Scomberesocidae). Flyingfishes are nested within halfbeaks, and sauries are nested within needlefishes. Optimization of jaw characters on the tree reveals a diverse array of evolutionary changes in ontogeny. During their development, needlefishes pass through a "halfbeak" stage that closely resembles the adult condition in the hemiramphid halfbeaks. The reconstruction of jaw transitions falsifies the hypothesis that halfbeaks are paedomorphic derivatives of needlefishes. Instead, halfbeaks make up a basal paraphyletic grade within beloniforms, and the needlefish jaw morphology is relatively derived. The parallel between needlefish ontogeny and beloniform phylogeny is discussed, and clades amenable to future morphological analysis are proposed.