cardinal vein absent (as in T. alalunga and T. 

 maccoyii). 



Posterior parasphenoid margin forming an angle, 

 becoming acute in large specimens (as in T. alalunga, 

 T. maccoyii, and, to a lesser degree, in T. obesus), 

 occasionally rounded in small specimens. Alisphe- 

 noids extending far ventrad into orbital cavity; dis- 

 tance from most ventral part of alisphenoid to near- 

 est point on parasphenoid goes into greatest height 

 of anterior part of orbit two times or more (only T. 

 maccoyii and larger specimens of T. tonggol have a 

 similar condition). Alisphenoids fused to para- 

 sphenoid in some larger specimens. Subopercle (see 

 fig. 9) relatively slender, its upper anterior margin 

 usually almost vertical in its lower two-fifths or 

 more, sloping posteriad in its upper portion (as in 

 T. maccoyii) ; rarely there is no vertical portion. 



Vertebrae 184-21 (as in all except T. atlaniicus). 

 First ventrally directed parapophysis on vertebra 8. 

 First closed haemal arch usually on vertebra 10 (as in 

 T. alalunga and T. maccoyii), sometimes on 11 (as 

 in the other five species). Anterior haemal prezyga- 

 pophyses arising high on haemal arch (as in T". 

 maccoyii and T. obesus). All haemal postzygapo- 

 physes short, less than half the centrum length (as in 

 T. maccoyii and T. obesus). Ventrolateral foramina 

 small, not more than one and one-half times width 

 of haemal spine (as in T. alalunga, T. maccoyii, and 

 T. obesus). 



Comparisons with T. maccoyii are given in table 5. 



Range 



T. thynnus thynnus has been found in the western 

 Atlantic from Hamilton Inlet, Labrador (La Monte, 

 1946 : 22) , and Newfoundland, south along the Atlan- 

 tic coast of the United States into the Gulf of Mexico 

 and Caribbean Sea (Wathne, 1959). It is known off 

 Venezuela ( Fernandez- Yepez and Santaella, 1956), 

 and south to northeastern Brazil. In the eastern 

 Atlantic, T. t. thynnus is found from the Lofoten 

 Islands of Norway (about 70° N.), south along the 

 coast of Europe and north Africa, south to the 

 Canary Islands. Records from near Cape Verde 

 Islands, Angola, and Republic of South .\frica have 

 been questioned (Tiews, 1963), but gill-raker counts 

 given by Talbot and Penrith (1963) for large speci- 

 mens caught from January to March suggest con- 

 vincingly that T. t. thynnus does occur west of the 

 Cape Peninsula of South Africa, and we have ex- 

 amined one specimen from there. 



Tag returns have shown that there is at least some 



interchange between eastern and western North 

 Atlantic T. i. thynnus. Mather (1960) reported two 

 specimens tagged off Martha's Vineyard, Mass., and 

 recaptured in the Bay of Biscay 2 to 5 years later. 

 Two large specimens tagged off Cat Cay, Bahamas, 

 were recaptured off Bergen, Norway, a distance of 

 over 4,000 miles, after 118 and 119 days at large 

 (Mather, 1962). 



T. thynnus orientalis has been reported in the 

 eastern north Pacific from the Shelikof Straits, north 

 of Kodiak Island, in the Gulf of Alaska (Radovich, 

 1961), off Vancouver Island (Neave, 1959), off 

 Willapa Ba}' and the mouth of the Columbia River 

 (Brock, 1938), regularly off southern California and 

 the length of Baja Calif. (Bell, 1963). In the west- 

 ern north Pacific, T. t. orientalis is known from the 

 island of Sakhalin in the southern Okhotsk Sea, 

 southward on both sides of Japan, to the northern 

 Philippines; eastward from Japan between about 

 30°-40° N. to about 160° W.; and eastward between 

 about 5°-10° N. from about 135°-175° E. (Yama- 

 naka et al., 1963). It is taken occasionally in 

 Hawaiian waters (Jordan and Jordan, 1922; Fowler, 

 1928; June, 1952a). 



The contention that both eastern and western 

 north Pacific T. thynnus constitute a single sub- 

 species is supported by the recapture off Japan of at 

 least three specimens that had been tagged 2 to 5 

 years previously near Guadalupe Island, Mexico 

 (Orange and Fink, 1963; Anonymous, 1964). 



Thunnus thynnus has been recorded from the 

 Galapagos area (Snodgrass and Heller, 1905; Herre, 

 1930), but there is no supporting evidence which 

 would eliminate T. maccoyii or anj^ other species from 

 consideration. 



Nakamura and Warashina (1965) reported T. 

 thynnus orientalis (as T. thynnus) from two areas 

 previously not verified. Two specimens, 2,657 mm. 

 and 2,200 mm., were taken in the Indian Ocean off 

 western Australia at 28°24' S., 105°56' E. and 27°43' 

 S., 102°25' E., respectively. .Another, 2,206 mm., 

 was captured in the southeastern Pacific at about 

 37°11' S., 114°41' W. Specimens from Chile had 

 previously been reported by Buen (1953, 1958), as 

 T. thynnus saliens. These are areas from which 

 T. maccoyii is known. Nakamura and Warashina 

 gave measurements of one specimen from each 

 locality. Converting their figures for pectoral length 

 into percent of fork length (their "total length") 

 gives 18.6 and 17.5 percent, falling below our data 

 for smaller T. maccoyii and agreeing well with T. 



AX.\TOMY AND SYSTAMATICS OF TUNAS 



119 



