( (''iiifril/iitioiis from the Zoolor/ical Lahorutonj of Iiidknia U nivcrsitij. 



No. 135.) 



Some Results from Studies of South 

 American Fishes 



By Carl II. Ekjenmann, 

 Professor of Zoology in Iiuliaiia University. Curator of I'islies, Carnegie 



Museum, Pittsburuh 



I. LINES AND METHODS OF EVOLUTION IN SOME 

 CHAR ACID FISHES 



In the first volume of the American CharacidBe, a study in 

 Convergent and Divergent Evolution,' which has just been com- 

 pleted, there are considered the Tetragonopteringe, Rhoadsinge, 

 Iguanodectina?, Stethaprioninse, Stichanodontinge, and the Glandu- 

 locaudinge. All but the last of these fall within Giinther's defini- 

 tion of the ' Tetragonopterina. ' There are recognized in the volume 

 just completed fifty-three genera, and two hundred and seventy- 

 five species, of which thirty-three genera, and one hundred and 

 seventy-one species were described during the preparation of the 

 'monograph, either by himself or by my students, chiefly Mrs. 

 Marion Durbin Ellis. 



The subfamily Tetragonopterinse, which is at present the dom- 

 inant group of tropical American fishes, was defined by Giinther 

 ( Catalogue of Fishes, British Museum, V, 1864) to include Pia- 

 bucina, Alestes, Brachyalestes, Chirodon, Chalceus, Brycon, Chal- 

 cinopsis, Chalcinus, Gasteropelecus, Piabuca, and Agoniates, be- 

 sides the genera listed below. Eliminating these genera, which 

 are now relegated to various separate subfamilies or which (Alestes 

 and Brachyalestes) are geographically extra-limital, there remain 

 of Giinther's South American Tetragonopterina: Tetragonop- 

 terus, Avith thirty-two species ; Scissor, with one species ; Pseudo- 

 chalceus, with one species ; Bryconops, with two species ; Creagru- 

 tus, with one species; making a total of five genera, with thirty- 

 seven species. 



Of the Iguanodectina^ which were included in Giinther's Tetra- 

 gonopterina he recorded two species belonging to the genus Piabuca. 



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