414 EIGHTH PACIFIC SCIENCE CONGRESS 



The tropical West-Atlantic-East Pacific shore fauna in the Pacific 

 extends from the Gulf of California and Lower California southward 

 to Ecuador and the very northern part of Peru, including the adjoining 

 offshore Clipperton, Cocos, and Galapagos Islands. 



Statements that the tropical East-Pacific shore fauna is trenchantly 

 distinct from the Indo-West Pacific are only partly correct. It is true 

 that the West-Atlantic-East Pacific has a very high percentage of distinct 

 endemic species, but there is a substantial percentage of species very 

 closely related, some the same, others of the subspecies level, common 

 to both regions— on the generic level there is a high percentage of genera 

 and subgenera common to both regions. This condition of closer re- 

 lationship is more pronounced in some families than in others, and in 

 a few families the close relationships are lacking. They are closer in 

 the Clipperton and Cocos Islands than along the Pacific American shores. 



The statements by Zoogeographers as summarized by Ekman (Zoo- 

 geography of the Sea, pp. 15-16, 1953) on the great distinctness of this 

 eastern Pacific fish fauna has been based to some extent on misinforma- 

 tion. This has resulted from studies by ichthyologists who have con- 

 fined their observations to limited faunal areas, resulting in conclusions 

 based on local faunistic concepts. There has never been published a 

 single paper comparing the genera or species common to these major 

 faunal areas. Too many systematic ichthyologists are individualistic 

 and have created numerous generic and specific names based only on 

 differences for the fishes of their local faunas. The result therefore 

 is to magnify differences by means of different names on the generic 

 and specific level whether important structural differences do or do not 

 exist. Zoogeographers base their differences between faunal areas to a 

 large extent on the percentage of different generic and specific names 

 occurring in faunal check-lists. Too many of these check-lists are pre- 

 pared by ichthyologists who know only their local faunas, and have 

 never had an opportunity to study widely ranging species and genera. 

 This lack of comparison of the wide-ranging species in wide-ranging 

 genera, and of genera in wide-ranging families, tends to cause zooge- 

 ographers to establish barriers that exist to some extent in scientific 

 names only. 



For example, conclusions have been made on the basis of the 1928 

 "Check-list of North and Central American Fishes" by Jordan, Ever- 

 mann and Clark. Ichthyologists are nearly unanimous in their opinion 

 that the check-list elevated hundreds of subgenera to generic level and 

 numerous genera to sub-family level. Thus when this check-list is com- 

 pared with others of a still more local faunal concept the number of 

 "distinct genera" by name is greatly multiplied. 



