Types of Nominal Species 



Thijrmus atlanlicus Lesson, 1830. Xo tyjje speci- 

 mens. Original description based on a specimen 28 

 inches total length (711 mm.), with a pectoral fin G 

 inches long (l.Vi mm.). Subtracting .')() mm., wo 

 obtain a fork length of about GGO mm. The pectoral 

 is about 23 percent of fork length; too sliort for 

 either T. albacarcs or T. atlanlicus (see fig. 2G), but is 

 nearer the latter. Lesson mentioned only two other 

 characters useful in identifying the species: a cop- 

 pery-red lateral band, and blue-slate coloied fins 

 (presumably also finlets). These appear sufficient 

 to associate the name alhinlicitf! with the blackfin 

 tuna, and we follow I^cebe and Tee-^'an (193()) and 

 later autliors in doing so. 



Scomber corctla Cuvier, 1820. No type specimen. 

 The first use of the name corctla for a tuna is usually 

 credited to Cuvier in Cuvier and Valenciennes 

 (1831), where he described Tlii/nnus corctla. The 

 original description, however, consists of a footnote 

 on page 198 of the second edition of Regne Animal 

 (1829), which refers only to Sloane (1707, vol. 1, 

 plate 1, fig. 3). Sloane 's figure is of "Scomber Major 

 torosus" and there is no way of associating it with 

 any known species, but this indication prevents the 

 name from being considered a nomcn nudum. 

 Scomber corctla Cuvier, 1829 must be regarded as a 

 nomen dubium. 



Thynnus corctla Cuvier in Cuvier and Valen- 

 ciennes, 1831. This later use of the name corctla is 

 based on a preserved specimen, MXHN A. 5380, 

 2G3 mm. fork length from Martinique. It is a black- 

 fin tuna with 19-1-20 vertebrae and a gill-raker count 

 of G -hi 7 (left) and 7-1-17 (right). 



Thynnus baltcatus Cuvier in Cuvier and \'alen- 

 ciennes, 1831. No type spe(nmens. Original de- 

 scription based on an unpublished illustration by 

 Lesson of the same specimen from which Thynnus 

 atlanticus was described, and, therefore, a synonym 

 of that species. 



Parathunnus rosengarteni Fowler, 1934. Holo- 

 type ANSP G0174, a stuffed skin G29 mm. fork 

 length. A count of gill rakers was impossible, but 

 our measurements show the pectoral fin to be 25.8 

 percent of fork length, characteristic of T. aUanlicus. 

 Parathunnus ambiguns Mowbray, 1935. No type 

 specimens. Original description based on Bermuda 

 specimens; gill rakers noted as G-|-17, swimbladder 

 "simple, broader than long, well forward," finlets 

 dusky with a trace of yellow. These characters 



unquestionably refer this nominal species to the 

 synonymy of T. atlanlicus. 



Characters 



Pectoral fin intermediate in length (generally simi- 

 lar to T. albacarcs and large T. obcsus), usually 22-31 

 percent of fork length. Dorsal and anal finlets in 

 fresh specimens lacking yellow. 



Gill rakers 19-25, resembling only T. longgol. 



I.,iver without striations on ventral surface, right 

 lobe long and narrow, no vascular cones on dorsal 

 surface (as in T. albacares and T. tonqgol). Spleen 

 located on right side, and stomach on left (as in all 

 except T. alalunga). 



Swimbladder either small, oblate, situated far 

 anteriorly, or resembling a poorly developed T. 

 albacares; when long, anterior and posterior cham- 

 bers divided by a membrane. 



Cutaneous arteries usually originating at level of 

 vertebra (J-8, passing laterally between ribs 5 and G, 

 branching between intermuscular l)ones G and 7 (as 

 in T. albacarcs, T. longgol, and T. obcsus). A single 

 row of arterioles and venules arises from each main 

 lateral cutaneous branch (as in T. albacarcs, T. 

 longgol, and T. alalunga), but from the lateral side of 

 each vessel (as in T. albacares and T. longgol). Post- 

 cardinal vein present, joining right cutaneous vein 

 (as in T. albacarcs, T. longgol, and T. obesus). 



Posterior parasi)lienoid margin rounded, concave, 

 or somewhat angulate (as in T. albacarcs and T. 

 ionggol), never with a pronouiu'ed angle. Parasphe- 

 noid concave in its anterior portion (seen occasionally 

 in small specimens of all other species). 



Vertebrae 19-1-20, with rare exceptions. First 

 ventrally dii-ected parapophysis on \ertebra 9 (as in 

 all except T. longgol and T. thynnus). First closed 

 haemal arch usually on vertebra 1 1 (as in all except 

 T. alalunga and some T. thynnus). Haemal arches 

 narrow, bowing widely, forming a large, ovate canal 

 (as in T. longgol). Anterior haemal prezygapo-, 

 phj'ses arising far ventrad on haemal arch (as in T. | 

 longgol and T. albacares). Longest haemal post- 1 

 zygapophyses equal to or longer than centrum (only 

 T. longgol and T. albacarcs approach this). Ante- 

 riormost ventrolateral foramina large, more than; 

 three times width of haemal spine (as in T. albacares 

 and T. longgol). 



Nominal species 



Beebe and Tee- Van (193G) established the validity 

 of T. atlanticus and placed Thjnnus baltcatus, Para- 



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U.S. FISH .VND WILDLIKK SERVICE 



