CATALOG OF LIVING WHALES 5 



able under Article 23(b). Two others (one invalid) are cited as generic or 

 subgeneric names for species densirostris but are not available under this 

 article. Still another pair are valid but not available under the article 

 as generic or subgeneric names for layardi. Similarly, one generic name 

 for europaeus and another for grayi are valid but not available. In sum, 

 this generation of specialists may erect a new generic or subgeneric name 

 for each of the 11 currently recognized species of beaked whales except 

 bidens, type of Mesoplodon, and hectori, type of Paikea Oliver, 1922. Under 

 Article 23 (b) the availability of this last generic name expires in 1972 

 unless it is used before that date in the primary literature as a senior 

 synonym. This anomalous state of affairs is not peculiar to beaked whales. 

 The same applies to the vast majority of generic, subgeneric, and specific 

 group names of all whales (not to mention all mammals) now treated as 

 junior synonyms. Their names are valid but not available under Article 

 23(b). Should future revisers find it necessary to recognize some of these 

 taxa, it would be simpler to propose new names for them than to repair 

 to the Commission on Zoological Nomenclature for rulings permitting re- 

 vival of pertinent old names. 



Classification. — Toothed and baleen whales represent divergent lines 

 of evolution, according to some students, and convergent lines of diphyletic 

 origin, according to others (cf. Kleinenberg, 1958, Doklady, Biol. Sci., 

 vol. 122, no. 5, p. 950). Present purposes, however, require a linear 

 arrangement of the species and all higher taxa. So far as is known, the 

 toothed whales (Odontoceti) are considerably older than the baleen whales 

 (Mysticeti) and are placed first. Using dentition as a primary character, 

 fresh water dolphins, particularly the Susuidae, are regarded as most 

 primitive. On the basis of the same criterion, a graded morphological 

 series can be made from susuids through delphinids, monodontids, phys- 

 eterids, and hyperoodontids to mysticetes. Evolution from the toothed to 

 the baleen condition is still marked in living forms by the absence of 

 functional maxillary teeth in the physeterids and by the occasional ap- 

 pearance of what may be rudimentary baleen in the palate of beaked whales 

 (cf. Baussard, 1789, Journ. Phys., vol. 34, p. 201). Presence of embryonic 

 teeth in baleen whales completes the series. 



Baleen whales can be arranged phylogenetically on the basis of general 

 form and, secondarily, on size. Rorquals clearly are less specialized than 

 right whales with their exaggerated heads, humps, and baleen plates. 

 Within each group or genus, the smaller and more typically formed or 

 streamlined species is regarded as the more primitive. The evolutionary 

 grade of other mysticete characters, taken singly or in combination, are in 

 accord with the form and size criteria used here. 



Principal works consulted on the evolution, classification, and biology 

 of whales are listed in the selected bibliography. Others are cited under 

 the generic and specific headings in the systematic section. 



