Fishes of the Western North Atlantic iii 



Genus Lamna Cuvier, 1 8 1 7 



Lamna Cuvier, Regne Anim., 2, 1817; 126, 127; type species, Squalus cornuiicui Gmelin, 1789, equivalent 

 to Squalus nasus Bonnaterre, 1788. 



Generic Synonyms: 



Lamia Risso, Hist. Nat. Europe merid., 5, 1826: 123; type species, Squalus cornubicus Gmelin, 1789; not 



Lamia Fabricius, 1775, for Coleoptera. 

 Selanonius Fleming, Hist. Brit. Anim., 1828: 169; type species, Selanonius walkeri Fleming, same as Squalus 



nasus Bonnaterre, 1788. 

 Exoles Gistel, Naturg. Tier., 1848: 9; to replace Lamia Risso, 1826; preoccupied. 



Generic Characters. Teeth slender, awl-shaped, smooth-edged, with lateral basal 

 denticles in most cases and perhaps in all, the first 2 teeth in each jaw similar in shape to 

 those succeeding, the anterior ones with two widely divergent roots, the third upper tooth 

 much smaller than second or fourth, but third lower tooth about same size as fourth j origin 

 of 1st dorsal over or anterior to inner corner of pectoral when latter is laid back; trunk 

 robust (Fig. 15); snout conical, pointed; caudal pits in the form of transverse furrows; 

 a less distinct secondary longitudinal keel, broadly triangular in cross section, on anterior 

 part of caudal on each side, close below the primary keel formed by the expanded caudal 

 peduncle, in all species so far known; upper jaw very slightly protrusible. Characters 

 otherwise those of the family. 



Range. Widespread in boreal to warm temperate belts of the oceans in both hemi- 

 spheres; not known from tropical seas. 



Sfecies. The genus Lamna is represented in the North Atlantic by the well known 

 Porbeagle (L. nasus, p. 112); in the North Pacific by a form that has usually been con- 

 sidered identical with nasus, but which has recently been found to be a distinct and well 

 marked species (L. ditropis Hubbs and FoUett, 1947);* in Australian-New Zealand 

 waters" and off Argentina* by close relatives whose precise relationships to nasus remain 

 to be determined; and in the eastern side of the South Pacific by a form (L. philippii Perez 

 Canto, 1886)^ resembling nasus in general appearance and in the position of the first 

 dorsal fin, but described and pictured as lacking lateral denticles on the teeth. Until it is 

 known whether this is actually the case, and whether or not philippii has the secondary 

 caudal keels (none are shown on the only published illustration of it), its status must re- 

 main problematical. 



4. Hubbs and Follett, Copeia, 1947: 194. 



5. L. luhitleyi Phillipps, N. Z. J. Sci. Tech., 16, 1935: 239, fig. 3; secondary caudal keels clearly shown in the 

 photograph. 



6. Reported as nasus by Lahille (An. Mus. nac. B. Aires, ^4, 1928: 310, pi. 4) ; teeth described as with denticles; 

 secondary caudal keels clearly shown on the illustration. 



7. Philippi, Anal. Univ. Chile, 71, 1887: 549, pi. 3, fig. 2. 



