DECAPOD CRUSTACEANS OF THE WEST INDIES 



29 



Ancestors of — 

 (from South America) 

 Potimirim 

 Guinotia 

 Trichodadylus 

 (in situ) 



Barbouria 

 (no evidence of source) 

 Attja 



Xiphocaris 

 Troglocubanus 

 Macrobrachium 

 Palaemon 

 Sesarma 



Available data do not allow postulates concerning the invasions by 

 a majority of the freshwater and terrestrial decapod crustaceans. 

 The origins of even the two endemic genera, Xiphocaris and Troglocu- 

 banus (the former monotypic and the latter represented by five 

 troglobitic members) , and the endemic Atya lanipes and Pachygrapsus 

 corrugatus are completely obscure. Further, all of the species classified 

 herein as terrestrial have marine larvae and are so widespread that, 

 while it must be assumed from a zoogeographic standpoint that all have 

 invaded each of the islands they occupy independently, this fact has 

 little bearing on an understanding of the relationships of the island 

 faunas to those of the continental masses. The same is true for those 

 forms that are widespread in estuarine habitats throughout the tropical 

 and subtropical western Atlantic. 



Nevertheless, there is evidence that seven and possibly nine stocks 

 have reached the islands from the Central American-Mexican region. 

 Three, possibly four, stocks have arrived from South America, one of 

 which reaches northw^ard only to Trinidad. No stocks appear to have 

 attained the islands directly from North America, and only the cam- 

 barine astacids (crayfishes) are believed to have utilized North America 

 as a center or origin, reaching the Antilles through the Central Amer- 

 ican-Mexican region. A single hippolytid, Barbouria cubensis, which 

 frequents brackish pools on Cuba, appears to have had its origin from 

 marine ancestors on the island, 



Endemism among the West Indian decapods, as illustrated below, 

 is only moderately spectacular and is largely confined to the Greater 

 Antilles. The numbers of freshwater and terrestrial species endemic 

 to individual islands and island groups are as follows (Isla de Pinos is 

 included herein with Cuba, and Isla Mona with Puerto Rico) : 



