ANODONTITES: A GENUS OF SOUTH AND CENTRAL 



AMERICxlN AND MEXICAN PEAELY 



FEESH-WATER MUSSELS 



By William B. Marshall 

 Assistant Curator, Dirisicn of Molhisks, United States JVudonal Museum 



The honor of describing the second South American naiad of any 

 kind fell to Bruguiere (1792«, p. 107) when he described Unio 

 (jranosa (now Diplodon granosus)} Certainl}^ the credit of describ- 

 ing the lirst genus of South American mussels fell to him in the same 

 year, Avhen he described the genus Anodontites (1792&, p. 131) and 

 the third known South American mussel, A. cris'pata^ in the same 

 paper. 



From the very start both this genus and species had a hard time 

 of it, and were knocked around from pillar to post, and it was not 

 until 1909 that they really began to ^Qt into the position to which 

 they were entitled. Many authors, in dealing with them, have made 

 serious errors. It is the object of this paper to correct as far as 

 possible ail errors that have been made regarding Anodontites and 

 the species (yi'ispata, and to give a complete account of the early 

 history of the genus and species, touching here and there upon the 

 history of various other genera, such as Unio and Anodonta. These 

 two genera hold such an important place in the history of the naiades 

 that in order to understand the group it is necessary to know some- 

 thing of their early history. The data given in this paper, it is 

 believed, will make the beginning of a study of the South American 

 mussels easy to any student who wishes to enter upon it. 



The first great forv/ard stride in the stnd}^ of the pearly fresh- 

 water mussels was in 1788, when the genus Unio was described to 

 include all those pearly, fresh-water mussels having cardinal teeth 

 or both cardinal and lateral teeth, a character that segregated them 

 from the marine mussels. The authorship of the genus is generally 

 credited to Eetzius (1788), but some credit it to his student Philipps- 

 son (1788). The following note by Simpson (1900, p. 679) explains 

 this matter completely : 



This genus w;^s described in a Miosis by Laurentius Miintor Pliilippsson under 

 his master, Retzius, in the Uni%-ersity of Lund, Sweden, and it is often credited 



1 So far as known the first mention in literature of any Soutli American pearly fresh- 

 water mussel was by Klein (1753), who described and figured Triquctra subviridis of 

 Guiana and Brazil. He being a uonbiuomial author, his name had to be rejected in favor 

 of Mya syrmatophova (now cal'ed Piisodoit sifrmatophora) Meusclien (1781). 



No. 2889.— Proceedings U. S. National Museum, Vol. 79, Art. 23. 



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