Osteology, Phylogeny, and Higher Classification 



of the Fishes of the 



Order Pleetognathi (Tetraodontiformes)^ 



JAMES C. TYLER' 



ABSTRACT 



The osteologj- of over 160 species of fossil and Recent plectognath or tetraodontiform fishes is 

 described and illustrated in relation to the supposed phylogeny and proposed higher classiflcation 

 (subfamilial to ordinal levels) of this group of approximately 320 Recent species of primarily tropical 

 and temperate forms of the Atlantic. Pacific, and Indian oceans. The history of the classification and 

 of the previous work on the osteology of the order is reviewed, while one new species (^ Acanthopleurus 

 collettei, Oligocene of Canton Glarus. Switzerland) and one new genus {lEotetraodon, Eocene of 

 Monte Bolca. Italy) are described. Comparative inclusive and exclusive definitions are given for all 

 higher categories based on both external and internal anatomical features. The Order Pleetognathi 

 (Tetraodontiformes) is divided into two suborders, the Sclerodermi or Balistoidei and the Gym- 

 nodontes or Tetraodontoidei, with a variety of other infraordinal and superfamilial categories, and 10 

 families, with subfamilial groupings in 4 of the latter. 



INTRODUCTION 



Preface 



The Pleetognathi are widely, but not unanimously, 

 recognized as one of the major orders or phyletic lines of 

 teleostean fishes derived of perciform ancestors. The 

 primary reason that there is any doubt concerning the 

 naturalness of the Pleetognathi, regardless at what tax- 

 onomic level it is recognized, is that it is a highly diver- 

 sified group for which adequate definitions have not yet 

 been given either for it as a whole or for most of its sub- 

 divisions. Until there appears and is accepted a con- 

 sistent and systematic general osteological survey and 

 comparison of the basic types of organization found 

 among the fossil and Recent species of plectognaths, 

 both generalized and highly modified, it will be impos- 

 sible to state without reasonable refutation that they are 

 all closely related, and more similar to one another than 

 to any other group of fishes. 



The aims of the present monograph are: first, to 

 anatomically define, especially with osteologically based 

 characters, the higher categories in the classification of 

 the plectognaths proposed here, these categories being 

 from the subfamilial to ordinal levels; and second, to in- 



Contribution No. 77-25M from the Southeast Fisheries Center Miami 

 Laboratory, Miami, Fla. 



'Southeast Fisheries Center Miami Laboratory, National Marine Fish- 

 eries Service, NOAA, Miami, FL 33149, and Research Associate, Depart- 

 ment of Ichthyology, American Museum of Natural History, New York, 

 NY 10024; present address; Office of Marine Mammals and Endangered , 

 Species, National Marine Fisheries Service, NOAA, 3300 Whitehaven 

 Street, N.W., Washington, DC 20235. 



terpret the phylogenetic relationships between these 

 divisions and most genera of the fossil and Recent Plee- 

 tognathi, dating back to the upper portion of the lower 

 Eocene, approximately 60 million years ago. 



This is done by pointing out, as much by illustrations 

 as by written descriptions, the many common os- 

 teological features of numerous representatives of each of 

 the families of plectognaths, including both relatively 

 generalized and specialized species when available. The 

 totality of these characteristics of the fossil and Recent 

 species demonstrates beyond question the distinc- 

 tiveness and phylogenetic naturalness of the plectognath 

 fishes, while at the same time providing the bases for the 

 detailed comparative diagnoses given here for the tax- 

 onomic subdivisions of the Pleetognathi. 



As classified here, the Order Pleetognathi (or 

 Tetraodontiformes), comprising today about 320 species 

 of mostly shallow-water, cireumtropical, and sub- 

 tropical marine forms, is divided into two suborders 

 (Sclerodermi or Balistoidei and Gymnodontes or 

 Tetraodontoidei), a variety of categories from infra- 

 orders to superfamilies, and into 10 families, in 4 of 

 which subfamilies are recognized. The Pleetognathi are 

 much more diversified than the great majority of fish 

 groups of a comparable number of species. Relative to its 

 comparatively few species, mostly marine, the Pleetog- 

 nathi are as highly diversified as that prime example of 

 diversity among fishes, the speciose freshwater characids 

 of South America and Africa. 



Just as interesting as the plectognath's diversity itself. 



