KENDALL AND BEHNKE: SALMONIDAE 



143 



Table 32. Characters that vary among the Salmonid Subfamilies. 



' Vladykov (li)70). 



■'Cavender (1970)- 



' Nordcn (1961 1, 



* Some vanation withm Salmonmae in these Iwo characters. Those with 2 cpurais usually have most extensive neural spine development. 



^ Sometimes erroneously termed dcrmosphenotic; sometimes present in Salmoninae; see Behnke (1968, p 9-10). 



the young grayling has much in common with that of both the 

 coregonines and salmonines" (Norden, 1961:743). 



Among the coregonines, larvae of Prosopium (Faber, 1970; 

 Auer, 1982), L«/c;c7!r/!V5 (Fish, 1932; Faber, 1970; Auer, 1982), 

 and Coregonus (¥'\%\\. 1932; Faber, 1970; Auer, 1982) have been 

 illustrated and briefly described. All show similar larval mor- 

 phology (Fig. 75). They are rather slender with a long preanal 

 finfold— the yolk being confined to the anterior trunk region. 

 The yolk-sac length is <35% total length (TL), eye diameter is 

 <7% TL, and body depth at anus is usually < 10% TL (Auer, 

 1982). The yolk is exhausted before any of the fins, except the 

 caudal, possess full complements of rays. Prosopium eggs have 

 multiple oil globules, while Leucichthys and Coregonus eggs 

 have a single oil globule (Auer, 1982). Pigment in preflexion 

 and flexion larvae is mainly associated with the dorsal and ven- 

 tral midlines. Later, the body becomes more uniformly pig- 

 mented. Prosopium develops parr marks during the juvenile 

 period. Larvae oi Stenodus are undescribed and they may differ 

 from those described above, since adults of this genus appear 

 quite divergent from the others in this subfamily. 



Early development of Thymallus thymallus has been fully 

 described (Penaz, 1975). They hatch with a large, anteriorly 

 placed yolk sac that is covered by a rather extensive vitelline 

 circulatory system, and the preanal and postanal finfolds are 

 about equal in length (Fig. 75). The yolk sac is exhausted during 

 notochord flexion and by that time some fin rays have developed 

 in all of the fins. The larvae are rather heavily pigmented during 

 this period. When the fins have developed their adult comple- 

 ment of rays, the fish appear like juveniles and parr marks begin 

 to form. 



Early development of all the salmonine genera and most sub- 

 genera is known, although several are inadequately described 

 (Table 33). Described development of all salmonines is quite 

 similar (Figs. 76, 77). Their eggs are among the largest of all 

 teleosts. They all hatch with large yolk sacs and well developed 

 vitelline circulatory systems. The preanal finfold is shorter than 

 the postanal finfold (except in Hucho where they are about 

 equal). The preanal finfold extends somewhat down the poste- 

 rior of the yolk sac in Oncorhynchus. The notochord is slightly 

 flexed and some caudal rays are present. Yolk-sac length is 



