XIX. SOME NEW SPECIES OF FISHES FROM THE RIO 



IGUASSU. 



By John D. Haseman.^ 



The Iguassu River rises in the Serra do Mar east of Curytiba, 

 Parana, near the Atlantic Ocean. It flows westward for about a 

 thousand miles over a sand-capped plateau, which is on the average 

 about one thousand meters above sea-level. The river has several 

 rapids and falls, the largest of which, the Salto de IguassU; is near its 

 junction with the Rio Parana. This fall is about two hundred feet 

 high and has a volume of water one-third larger than that of Niagara. 

 In a distance of about one thousand miles the river descends nearly 

 three thousand feet. I feel sure that the Salto de Iguassu is older than 

 the present fauna of the lower La Plata. 



The fauna of the upper isolated Iguassu is remarkable. There 

 are no turtles and no alligators. There are about twenty-five species 

 of fishes. Most of these have near relatives in neighboring streams, 

 and indeed many of them diff'er very little from their relatives in 

 the near-by streams, but their constant variation in this region, iso- 

 lated as they are by the large Iguassu Falls, gives warrant for describ- 

 ing them as new. 



The origin of this ichthyic fauna is in doubt. Stream piracy has 

 not taken place, and cannot explain the peculiar life of the upper Igu- 

 assu basin, for the fishes of the headwaters of highland streams do not 

 exist in the basin. The Indians and natives told me of cases where 

 they had taken fishes from below the water-falls to above them, and 

 it is possible that some of them have been brought up thither in that 

 way. The long-necked bird, "biguas," nearly always carries cat- 

 fishes, especially the mailed cat-fishes, which it has caught, to stones, 

 and beats them to death before swallowing them. On one occasion I 

 saw one of them fighting with another bird of the same species over a 

 fish, which it had caught below the Avanhandava Falls of the Rio 

 Tiete, and which it dropped into the river above the fall. Such 



' This is the fifth article pubHshed by the Carnegie Museum upon the results of 

 the Expedition to Central South America, 1907-1910. 



374 



