4 ELOPIFORM FISHES 



SYNOPSIS 



The skeletons of the Recent elopiform fishes (Elops, Tarpon, Megalops, Pterotlirissus, Albula) 

 are described, and all fossil genera thought to be correctly placed in the Elopiformes are reviewed 

 and compared with the living forms. From the descriptions it is concluded that the classification 

 of the Elopiformes given by Greenwood et al. (1966) reflects the phylogeny of this group. A 

 new family, the Osmeroididae, based on the Cretaceous genus Osmeroides, is included in the 

 suborder Albuloidei as the basal family of that suborder. The Osmeroididae provide a link 

 between the Elopoidei and the more specialized Albuloidei. Primitive and advanced features 

 of the Elopiformes are discussed together with individual discussions of the contained suborders. 

 Three new fossil genera are established : Davichthys, Protarpon and Lebonichthys. The relation- 

 ship of the Elopiformes with other basal teleost groups is considered and it is concluded that 

 although no relationship exists with the Clupeomorpha and Osteoglossomorpha within the 

 Teleostei, the possibility of a relationship with the Euteleostei cannot be ruled out. 



I. INTRODUCTION 



This work is a taxonomic revision of the order Elopiformes Greenwood et al. (1966). 

 The Elopiformes are a group of primitive teleosts related to the highly specialized 

 Anguilliformes and Notacanthiformes by virtue of the fact that members of all 

 three orders show a leptocephalus larval stage in their life history. The elopiforms 

 are represented in the Recent fauna by a handful of genera ; Elops, Megalops, 

 Tarpon, Albula, Dixonina and Pterothrissus. There are more fossil genera, found 

 from the Upper Jurassic onwards. Woodward (1901) lists eighteen genera while 

 Romer (1966) includes some forty-six in the Elopiformes. Although many of these 

 fossil forms do not appear to be members of the Elopiformes, it remains true that the 

 order is largely constituted by extinct genera. 



Most fossil elopiforms are known from Upper Cretaceous deposits and were 

 originally described in several faunal works. The more important of these works 

 are those of Agassiz (1833- 1844) in which forms from several localities were dealt 

 with ; Dixon (1850) described the English Chalk species ; Pictet (1850), Pictet & 

 Humbert (1866), Davis (1887) and Hay (1903) described those from the Lebanon. 

 Marck (1858, 1863) noted forms from the Westphalian Chalk and Cope (1872), 

 Loomis (1900) and Stewart (1898) were concerned with those from the Kansas 

 Chalk. This earlier work was synthesized by Woodward (1901) who went on to 

 deal extensively (1907, 1908) with the English Chalk fauna. In more recent years 

 d'Erasmo (1946) has published on the Upper Cretaceous fauna from Comen, Yugo- 

 slavia, Arambourg (1954) has described elopiforms from the Cretaceous of Morocco 

 and a revision of the Westphalian fauna has been undertaken by Siegfried (1954). 



Important work on the anatomy and taxonomy of certain fossil genera has been 

 published by Nybelin (1967b) and Gaudant (1968) for Anaethalion, and by Goody 

 (1969a) for Sedenhorstia. Recent elopiforms have received attention in faunal 

 works by Barnard (1925), Fowler (1936), Okada (i960) and Hildebrand (1963). 

 Finally, important contributions to the anatomical features of the Recent forms 

 have been made by Ridewood (1904), Hollister (1936, 1939), Nybelin (1956, 1967a, 

 1971) and Greenwood (1970a). Apart from these specific references the genera Elops 

 and Megalops have often been referred to in papers concerned with phylogeny 

 and comparative anatomy. 



