540 



ALLAN HANCOCK PACIFIC EXPEDITIONS 



VOL. 2 



SPECIES COLLECTED FROM THE GALAPAGOS ISLANDS 

 AND THEIR RELATIONSHIPS 



Of the 82 species collected, 39 occurred in the Galapagos Islands. 

 These 39 species may be considered in two groups: (a) endemic and (b) 

 nonendemic species. 



Twenty-one species (all new) were endemic to the Galapagos Islands. 

 Their relationship to other regions can be suggested by the distribution of 

 their closest related species. In most but not all instances some certain 

 other species can be recognized as the most closely related species. Eight 

 species have nearest related species in the region of Tortugas, Florida ; 4 

 have nearest relatives along the Pacific coast of Mexico ; 3 have nearest 

 relatives in Japanese waters; 2 have nearest relatives in the northern 

 American Pacific. In no case was a nearest related species found along the 

 Pacific coast of South America (where an equal number of fishes was 

 examined). Nearest related species were not clearly evident in the case 

 of 4 species. The following list shows these relationships. 



TABLE 5 

 Distribution of Nearest Relatives of Endemic Galapagos Species 



Endemic Galapagos species with nearest related species occurring in the 

 tropical Atlantic (species marked with an asterisk (*) occur elsewhere only 

 in the Atlantic, as far as is known) 



Galapagos Species 



Nearest Related Species and Its Locality 



1. Lecithochirium 



maffnaporum 



2. Leurodera pacifica 



3. Lepidapedon hancocki 



4. Lobatostoma pacifica 



L. microstomum 



L. decora* 

 L, nicolli* 

 L. kemostoma* 



5. Plagioporus gastrocotylus P. crassigula* 



6. Prosorhynchus pacificus P . atlanticus* 



7. Stephanostomum anisotremi S. senium* 



8. Teirochetus proctocolus T. coryphaenae 



Gulf of Mexico ; 

 Galapagos 

 Tortugas, Florida 

 Tortugas, Florida 

 tropical American 



Atlantic 

 Tortugas, Florida 

 Tortugas, Florida 

 Tortugas, Florida 

 Tortugas, Florida 

 Japan 



B. Endemic Galapagos species with nearest related species occurring along the 

 Pacific coast of Mexico 



1. Apocreadium 



A. mexicanum Pacific Mexican coast 



Choanodera or Pacific Mexican coast ; 



Apocreadium Galapagos 



O. mexicanus Pacific Mexican coast 



O. acuta Pacific Mexican coast 



longisinosum 

 2. Myzotus miellosus 



3. Opecoelus xenistii 



4. Opegaster pentadactyla 



