PROCEEDINGS OF THE UNITED STATES NATIONAL MUSEUM 



by the 



SMITHSONIAN INSTITUTION 



U. S. NATIONAL MUSEUM 

 Vol.91 Washington: 1942 No. 3132 



THE SPECIES OF AEGLA, ENDEMIC SOUTH AMERICAN 

 FRESH- WATER CRUSTACEANS ' 



By Waldo L. Schmitt 



Widely distributed throughout the greater part of temperate South 

 America from about latitude 20°30' S. (Franca, Sao Paulo, Brazil) 

 to latitude 40° 28' S. (Abtao, Llanquihue, Chile) is the unique, ende- 

 mic genus of fresh-water decapod Crustacea known as Aegla (family 

 Aeglidae). Its nearest relatives are marine and probably to be found 

 somewhere among the galatheids (tribe Galatheidea). There are no 

 fresh-water Crustacea at all like Aegla anywhere else in the world. 



Most authorities have believed the genus monotypic — genotype, A. 

 laevis (Latreille), 1818 (pi. 308, fig. 2). In so doing they certainly 

 must have considered differences that are at times rather marked 

 between specimens from widely separated places, or in some instances 

 from the same locality, as variations of no great importance, or else 

 were possessed of altogether too little material to be able to evaluate 

 it properly. Carlos Moreira (1901), at the time a member of the 

 zoological staff of the Museu Nacional, Rio de Janeiro, Brazil, was 

 the first to dissent, insisting and, indeed, demonstrating that at least 

 the species described by Fritz Miiller (1876) as A. odebrechtii was 

 distinct from A. laevis. For his Brazilian specimens, regrettably, 

 INIoreira employed the name Aegla intermedia., which had been given a 



iThis paper was first presented as an illustrated address, entitled "Some Remarks on 

 the Endemic South American Freshwater Crustacean Aegla laevis (Latreille)," before 

 Section II, Biological Sciences, of the Eighth American Scientific Congress, Washington, 

 May 16, 1940. An abstract of this address appears in the Proceedings of that Congress, 

 vol. 3, p. 491, 1942. 



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