86 ELOPIFORM FISHES 



Remarks. The genus Sedenhorstia contains four species. 5. granulata (Marck) 

 from the Campanian of Sendenhorst, S. libanica (Woodward) from the Middle Ceno- 

 manian of Hakel, Lebanon, and S. dayi (Hay) and S. orientalis Goody, both from 

 the Middle Cenomanian of Hajula, Lebanon. 



The Lebanese species are the best known and have been the subject of a study by 

 Goody (1969a) who removed the genus from the Scopelidae (sensu Woodward 1901) 

 to the suborder Elopoidei. Goody (1969a) described S. dayi in some detail and 

 indicated many similarities with Recent Elops and Megalops, although no indication 

 was given as to which of these Recent forms it was more nearly related. Goody 

 (1969a) suggested that the genus be placed in a monotypic family, the Sedenhorstii- 

 dae, based upon the presence of ossifications within the dorsal median ligament 

 between the occiput and the origin of the dorsal fin. The establishment of a separate 

 family, equal in status to the Megalopidae and Elopidae, seems unjustified on this 

 basis alone, particularly as calcification within the dorsal ligament is not unique to 

 Sedenhorstia (Goody 1969a : 20-21). A survey of the characteristics of Sedenhorstia 

 indicates affinity with the Megalopidae and it is suggested that the genus be placed 

 in this family. The salient points are discussed below. 



The general body form of Sedenhorstia resembles that of the Recent megalopids 

 rather than elopids ; the cranium is moderately deep with respect to its length, the 

 orbit is large and the mouth is almost superior. The body was probably slightly 

 compressed, as evidenced by the straight pleural ribs which nearly encircle the 

 abdominal cavity. In megalopids the body is also compressed while in the Elopidae 

 it is rounded. The vertebral column is composed of approximately 50 vertebrae of 

 which 25 are caudal and is similar to Tarpon in which there are 53-57 vertebrae of 

 which 20-24 are caudal. Megalops exhibits a higher count (c. 68) and is thus like 

 Elops species in which the count varies from c. 63 in E. machnata to c. 80 in E. saurus. 



The dorsal fin is situated more posteriorly than in Elops or the megalopids and is 

 composed of more rays (23). In this respect Sedenhorstia is distinctive. The anal 

 fin, however, is decidedly megalopid in being long and composed of at least 22 rays. 

 The first anal pterygiophore is also similar to Megalops and Tarpon, exhibiting a close 

 approximation with the vertebral column. The typical megalopid feature of an 

 elongate terminal dorsal and anal lepidotrich is not seen in Sedenhorstia. The origin 

 of the pelvic fin in Sedenhorstia occurs anterior to the level of the dorsal fin origin 

 (in S. orientalis the pelvic and dorsal origin are at the same level), and is thus similar 

 to Tarpon. 



The caudal skeleton is of the basic elopoid (or leptolepid) type. In possessing a 

 half spine upon the second preural centrum Sedenhorstia is primitive (Patterson 

 1968b) and resembles Elops rather than Megalops or Tarpon, but some specimens of 

 Megalops do show a half spine and perhaps little significance can be attached to this 

 feature in this instance. The base of the first uroneural is unforked and no urodermal 

 has been found, conditions which are unlike Elops but in accordance with mega- 

 lopids. A typical megalopid feature of Sedenhorstia is the retention of fringing fulcra 

 on the upper margin of the caudal fin. S. dayi possesses three such elements while 

 there are five in S. libanica. In the number of fringing fulcra Sedenhorstia therefore 

 resembles Megalops rather than Tarpon in which there are rarely more than two. 



