VIII 



THE EVOLUTION OF BONY FISHES 



1 . Classification 



Class Actinopterygii 

 Superorder i. Chondrostei 



Order i. Palaeoniscoidei. Devonian-Recent 



*Cheirolepis; *Palaeoniscus; * Amphicentrum; *Platysomus, 

 *Dorypterus ; *Cleithrolepis; *Tarrasius; Polypterus, bichir 

 Order 2. Acipenseroidei. Jurassic-Recent 



*Chondrosteus; Acipenser, sturgeon; Polyodon, paddle-fish 

 Order 3. Subholostei. Triassic-Jurassic 

 *Ptyeholepis 

 Superorder 2. Holostei. Triassic-Recent 



*Acentrophorus; *Lepidotes; *Dapcdius; *Microdon; Amia, 

 bowfin; Lepisosteus, gar-pike 

 Superorder 3. Teleostei. Jurassic-Recent 

 Order 1. Isospondyli 



*LeptoIepis; *Portheus; Clupea, herring; Salmo, trout 

 Order 2. Ostariophysi 



Cyprinus, carp; Tinea, tench; Silurus, catfish 

 Order 3. Apodes 



Angnilla, eel; Conger, conger eel 

 Order 4. Mesichthyes 



Esox, pike ; Belone; Exoeoetus, flying fish ; Gasterostens, stickle- 

 back; Syngnathns, pipe-fish; Hippoeampus, seahorse 

 Order 5. Acanthopterygii 



*HopIopteryx; Zens, John Dory; Perca, perch; Labrus, wrasse; 

 Uranoscopns, star gazer; Blennins, blenny; Gadus, whiting; 

 Pleuronectes, plaice; Solea, sole; Lophius, angler-fish 



2. Order 1. Palaeoniscoidei 



The actinopterygian stock has been distinct since Devonian times. 

 The early representatives lacked many of the specializations that we 

 find in the successful bony fishes today and showed features of simi- 

 larity to the Crossopterygii. These Devonian Actinopterygii had not 

 yet acquired the striking signs of full mastery of the waters, which are 

 so characteristic of the group today. They resembled their ancestors 

 the placoderms and their cousins the crossopterygians in being rather 



