FOSSIL AND RECENT 29 



Davichthys dubius (Davis) 

 (Text-figs. 12, 13) 



1887 Osmeroides dubius Davis : 565, pi. 31, fig. 4. 

 1901 lOsmeroides gracilis Davis ; Woodward : 16. 



Diagnosis. Davichthys reaching 70 mm S.L. Skull roof with faint ornamentation 

 on the frontal bones above the orbit. Maxilla with straight oral margin ; supra- 

 maxillae large ; premaxilla shallow, forming about one-quarter of the oral margin 

 of the jaw. Preopercular sensory canal running at the anterior margin of the bone. 

 Dorsal fin situated in the centre of the back and composed of 15 rays. Anal slightly 

 nearer to the caudal peduncle than to the pelvic fin and composed of 16-17 rays. 

 Caudal fin with fringing fulcra. 



Holotype. Nearly complete fish, R.S.M. 1891.59.38, from the Upper Santonian 

 of Sahel Alma, Lebanon. 



Material. The holotype and the following specimens were examined : R.S.M. 

 1891.59. 147, B.M.N.H. 48155 and 46539. All are from the Upper Santonian of 

 Sahel Alma, Lebanon. 



Description. The anatomy of Davichthys is very like that of Elops and Anae- 

 thalion and distinguishing characters are few and minor. In several respects 

 Davichthys is intermediate between Elops and Anaethalion. 



The head, as in all elopids, is relatively shallow and the gape moderately large. 

 The skull roof is similar to Elops and Anaethalion in being flat, with medially united 

 parietals and with frontals which are narrow and parallel-sided above the orbit but 

 widen considerably above the otic region. In contrast to Elops and Anaethalion 

 the frontal of Davichthys is ornamented above the orbit by weak ridges. The 

 dermethmoid is flat, as in all elopoids, and does not bear the ventro-lateral pro- 

 jections seen in some species of Anaethalion (Nybelin 1967b : fig. 4B). The absence 

 of such projections is a resemblance to Elops. An ethmoid commissure could not 

 be identified in the specimens examined. 



The neurocranium is shallow with the narrow, straight parasphenoid lying almost 

 horizontally, as in other elopids. Anteriorly the vomer bears a rounded tooth plate 

 which carries a dentition of small pointed teeth. Whether the vomerine tooth plate 

 was paired or not could not be seen. 



The hyomandibular is attached to the neurocranium by a single broad head and 

 the shaft is inclined posteriorly, as in Elops and some species of Anaethalion. While 

 most elopids have an undivided hyomandibular head Elops saurus shows a clear 

 division into anterior and posterior portions (cf. Ridewood 1904 : fig. 10). 



The metapterygoid overlaps both the hyomandibular and the endopterygoid and 

 is unusual among elopids in being deeper than long. The quadrate is also distinctive 

 in that the anterior border is longer than the posterior. As in Elops and Anaethalion 

 the quadrate does not have a well-defined facet behind the articulatory condyle as 

 it does in megalopids. In the remainder of the hyopalatine series there is a close 

 similarity with other elopids. Thus the ectopterygoid is narrow and shows a ridge 



