Fishes of the Western North Atlantic 



37 



ware River at Bay-at-Green Creek, Cape May County, 

 New Jersey, in salt water. May 5, 1907, ANSP 25471; 

 4, from Delaware River at Torresdale, Philadelphia 

 County, Pennsylvania, in fresh water, November 

 191 1, ANSP 44298-44301; 3, 470-580 mm FL, 

 from Delaware River, March 29-31, 19 13, USNM 

 1258 16-125818 ;^2 I young, 185 mm FL, Salmon 

 Creek, North Carolina, USNM 64330; i of head, 

 fins, and dried strips of skin with plates, from Poto- 

 mac River, USNM 26273; 3 stuffed specimens in 

 Paris Museum.^^ 



Distinctive Characters. A. brevirostris is distin- 

 guished from A. oxyrhynchus by blackish viscera, a wider 

 mouth (see Key), the absence of a fontanelle, almost 

 complete absence of the postdorsal shields, and by 

 preanal shields arranged in a single row. Also, indi- 

 viduals of A. brevirostris assume adult proportions 

 when they are only about two feet TL; A. oxyrhynchus 

 retains juvenile characteristics even up to four feet. The 

 most conspicuous difference between brevirostris and 

 fuhescens is in the lateral scutes, which are much 

 paler than the background in the former but of the 

 same shade as the background in the latter. 



Description. Scutes in all five main rows not 

 closely set and rather weakly developed in adults in 

 comparison with other eastern American species, but 

 sharp and set close together in a young specimen 

 7.75 inches FL (USNM 64330); in 12 specimens, 

 8-13 (av. 10) dorsal shields, 25-32 (av. 28) lateral 

 shields, and 7— 1 1 (av. 8) ventral shields; shields be- 

 hind dorsal fin either in a single row or paired; elon- 

 gated fulcrum at base of lower caudal lobe shorter 

 than base of anal fin. 



Head averaging 2 2''/o of FL in adult, 28 "/o in 

 a young specimen 7.75 inches FL. Fontanelle ab- 



22. According to the tag, these specimens were submitted as "young 

 Sturgeon" (presumably as A. oxyrhynchus) for identification. 



23. Details on these specimens are given by Bertin (z2: 252). Two of 

 these fish were sent to the Paris Museum by LeSueur, apparently 

 as paratypes. 



Figure 8. Acipenser brevirostris. Lateral view of spawning female, 

 580 mm long, from the Hudson River near Kingston, New York. 



