148 



ONTOGENY AND SYSTEMATICS OF FISHES-AHLSTROM SYMPOSIUM 



large mouth w 7i3 

 many small teeth n 753 

 ^large toothed vomer 



^ N 720 



no teeth on vomer 



N 720 



/ 



mostly: 

 small mouth n 7S3 

 small teeth on vomer 

 of young only n=720 



parr marks absent n 743 

 two flaps between nostril n 71 

 enlarged first supraorbital n 71 

 Joss of basibranchial plate n 71 



/ \\ 



N 727 slightly notched ethmoid 

 cartilage 



light spots 1 

 Palatine vomer strong ascending pre- 



teeth form z^ maxillary process J n 



j" shaped "C gap between palatine I 



band n 753^v vomer teeth 1 



Thymallinae 



N 72S notched ethmoid 



\ cartilage 

 N 732 palatine vomer 

 teeth form a "T" 



/ 



Coregoninae 



N 679 no teeth on maxillary 



c 9 one urodermal 



c 11 small neural spine on PU^ 



N-753 < 16 dorsal rays 



N-750 general loss of teeth 



c 11 small neural spine on PU-, 

 N-679 > 16 dorsal rays 

 N-e79 no orbitosphenoid 



increase in size and amount of yolk in egg 

 bypass larval stage 



Salmonidae 



100) 



• N 739 



• •N 752 

 ♦IM 743 

 *N 752 



• N 752 



• *C 27 



• • N 752 



• •rj 752 



• *N 752 



• "N 752 



• •C27 

 «»C 11 



• *c n 



*?C9 



Tetraploid karyotype ( 2n chromosomes - ' 



Axillary pelvic process 



Three upturned caudal vertebrae ( two ural centra) 



Parr marks in juveniles 



Three post cleithra 



Mesopterygoid toothless 



Last four hemal spines and parhypural fit together ( peg and socket) 



Adipose fin present 



Oviducts incomplete or absent 



Mesocoracoid present 



Opisthotic present 



Principal caudal rays = 19 



Three epurals 



Full neural spine on PU, 



Two hypurais (ventral) on U^, 4 hypurals (dorsal) on U, . 



1 long, 2 short uroneurals 



N 726 blunt pointed ethmoid cartilage 

 N 732 gap between palatine vomer teeth 

 M '53 no ascending premaxillary process 

 N 753 postorbitals contact preopercular 

 N 753 opisthotic touches prootic 

 N 728 reduced dorsal fontanelles in adult 



well developed stegural 



expanded caudal neural and 



hemal spines 



neural spine on PU. 



large neural spine on PU, 

 N-679 parietals separated by 



supraoccipital 

 N 739 small scales ("> 100 in 



lateral Ime) 

 N-679 suprapreopercular present 

 N 731 curved preopercular 

 N 736 dorsal rays < 16 

 e-9 reduction or loss 



of hypethmoid 



B - Behnke 1968 

 N - Norden 1961 

 C - Cavender. 1970 

 H = Hol£ik,1982 



(number refers to page 



in above references) 

 * Salmonidae (synapomorph for family) 

 "" Salmonoidei (synapomorph for suborder) 

 ■•• Shared primitive (plesiomorph) character 



with other "primitive" teleosts 



Fig. 78. Hypothesis of relationships among extant saimonid genera. Groupings and branching points are based largely on a consensus of recent 

 literature and are not the result of a strict cladistic analysis. 



possessed by salmonids include lack of oviducts, presence of 

 abdominal pores, and three upturned caudal vertebrae sup- 

 porting the hypurals. Salmonids are autapomorphic with about 

 twice the DNA content of other '^salmoniform" families, ap- 

 parently the result of having a common tetraploid ancestor. The 

 salmonids possess an adipose fin, a mesocoracoid, pyloric caeca, 

 and the vestige of a spiral valve intestine. The gill membranes 

 extend far forward free from the isthmus and there is a pelvic 

 axillary process. Two shared derived features of the salmonids 

 and neoteleostei are: 1) the articulation of both the basioccipital 

 and exoccipital with the first vertebra, and 2) the presence of a 

 medial cartilage between the ethmoid and premaxilla (Fink and 

 Weilzman, 1982). 



Although it is not possible at present to perform a meaningful 

 cladistic analysis of the salmonids, some evidence is available 

 in the literature which can contribute to such an analysis (Fig. 

 78). Cavender (1970) compared the osteology of leptolepids. 

 extinct fish thought to represent the basal teleost condition, with 

 that of the salmonids. He found several characters that indicated 

 1) that the salmonids are monophyletic, and 2) how the three 

 subfamilies of salmonids are interrelated. The coregonines ap- 



peared to be most similar to the leptolepids, the thymallines 

 more derived than the coregonines, and the salmonines more 

 derived than the thymallines. Reshelnikov (1975). on the basis 

 of several types of characters, suggested elevating the subfamilies 

 to familial status. 



Coregoninae contains about 30 species in three genera. They 

 are mainly freshwater, and produce rather small eggs, compared 

 to those of the other two subfamilies. They share several ad- 

 vanced characters with the other subfamilies, indicating that 

 salmonids are monophyletic, but lack a number of advanced 

 character states possessed by the other two subfamilies, as these 

 branched oflTafter the coregonines. Within the coregonines, Pro- 

 sopium seems least diverged (Table 34). Sienodus shows several, 

 possibly secondarily derived character states concordant with 

 feeding on large active prey (expanded dentition, large mouth). 

 Coregoniis, which seems to be a sister group to Stenodus. is 

 separated into two subgenera: Leucichthys with adaptations for 

 plankton feeding, and C orego nus y^h\ch are mainly benthic feed- 

 ers. 



Thymallinae contains one genus, Thymallus, with about four 

 species in freshwater of the colder parts of the Northern Hemi- 



