type material, we do not deem it necessary or proper 

 to taive this action ourselves. 



Bleeker's original description was based on a single 

 specimen, 650 mm. long, from "Batavia, in mari," 

 with a pectoral fin shorter than the head and no 

 swimbladder. The description obviously applies to 

 the species for which the name is now used. 



Thunnus rarus Kishinouye, 1915. No type 

 specimens. Original description based on a single 

 specimen, 28.8 inches (ca. 730 mm.) long, from 

 Nagasaki. The gill-raker count of 0+17, short 

 pectoral fins (no measurements given), and lack of 

 swimbladder show this nominal species to be a 

 synonym of T. tonggol. 



Thmnusnicolsoni Whitley, 1936. Holotype Aus- 

 tralian Museum lA. 6553, a 189 mm. head of a 

 specimen originally 30 inches (762 mm.) total length 

 caught between Lindeman and Maher Islands, 

 Cumberland Group, North Queensland, Au.stralia. 

 The gill raker count of 6+16 and pectoral shorter 

 than head establish this as a synonj^m of T. tonggol. 



Characters 



Pectoral fin (see fig. 26) varying in length from 

 medium (22-31 percent of fork length) in specimens 

 less than 600 mm. to short (16-22 percent) in those 

 over 600 mm. (the latter resembling only T. thijnnus 

 and T. maccoyii). Tail region comparatively long, 

 longest in large specimens; distance from snout to 

 second dorsal origin 49-55 percent of fork length, 

 decreasing with size (consistently lower than in any 

 other Thunnus species). 



Gill rakers 19-26 (rarely to 28), fewer than in any 

 other Thunnus species except T. atlanlicus. 



Liver without striations on ventral surface, its 

 right lobe long and narrow, without vascular cones 

 on its dorsal side (as in T. albacares and T. allanticus). 

 Spleen on right side, stomach on left (as in all e.xcept 

 T. alalunga). Kidney with a bulky anterior mass 

 and a long, narrow tail, reaching vertebra 15-17. 



Swimbladder absent or rudimentary. 



Cutaneous arteries originating at the level of 

 vertebra 7-8, passing laterally between ribs 4 and 5 

 or 5 and 6, dividing between intermuscular bones 6 

 and 7 (as in T. albacares, T. ohesus, and T. allanticus). 

 A single row of arterioles and venules arising from 

 each cutaneous branch (as in T. alalunga, T. alba- 

 cares, and T. atlanticus), but arising from the lateral 

 side of each vessel (as in T. albacares and T. atlan- 

 ticus). 



Post-cardinal vein present (as in T. albacares, T. 

 atlanticus, and T. obesus). 



Posterior parasphenoid margin not angulate (simi- 

 lar to T. albacares and T. atlanticus). 



Vertebrae 18 + 21 (as in all except T. atlanticus). 

 First ventrally directed parapophysis usually on 

 vertebra 10. First closed haemal arch usually on 

 vertebra 11 (as in T. atlanticus, T. albacares, T. 

 obesus, occasionally T. thynnus) or 12. Anterior 

 haemal prezygapophyses arising well ventrad on 

 haemal spines (as in T. albacares and T. atlanticus). 

 Haemal postzygapophyses long, the longest about 

 equal to or longer than centrum length (as in T. 

 atlanticvs, slightly longer than in T. albacares). 

 Anteriormost ventrolateral foramina large, more 

 than three times as wide as haemal spine (as in T. 

 albacares and T. atlanticus). 



Nominal Species 



There appear to be only two synonyms of T. 

 tonggol: Thunnus rarus Kishinouye from .Japan and 

 T. nicolsoni Whitley from Queensland. Rivas 

 (1961) placed T. nicolsoni in the synonymy of T. 

 albacares but the gill raker count of 6+16 = 22 alone 

 (Whitley, 1936) is enough to show that this is in- 

 correct. 



Range 



T. tonggol is limited to the Indo-West Pacific. It 

 is found from the western and southern coasts of 

 Kyushyu and the southwestern part of the Japan 

 Sea (Kishinouye, 1923, p. 449), south through the 

 Batavia Sea (Bleeker, 1851, p. 356) to New Guinea, 

 New Britain, and the entire north coast of Australia 

 (Serventy, 1956b). On the Australian east coast, 

 it is reported at least as far south as Twofold Bay, 

 New South Wales; on the west coast it reaches at 

 least to Cockburn Sound in the Freemantle area. 

 Its range in the Indian Ocean (Jones, 1963) includes 

 the Indo-Australian Archipelago, Andaman Islands, 

 both coasts of India, southern Arabia, the Somalia 

 coast, and the Red Sea, but it was not reported from 

 East African waters by Williams (1964) or Merrett 

 and Thorp (1966). 



Gill-raker counts indicate differences between 

 populations in the western Indian Ocean, with a 

 modal number of 26, and those in the eastern Indian 

 Ocean and western Pacific, with a mode of 23. 

 More data are necessary to corroborate this. 



ANATO.MY .\ND SYSTEMATICS OF TUNAS 



121 



