87 



(see Overall Parsimony Analysis). In any case, the distinction between the two states 

 appears to be minor and somewhat arbitrary, with the "horizontal" condition really 

 representing only a slight horizontal shift to a roughly diagonal position. As no 

 unambiguous data for any species could be determined, either from study skins or from 

 photographs, this character was subsequently deleted. 



3) shape of anterior margin of premaxilla in dorsal view: 0 = flat, square, or bi-lobed; 1 

 = tapered and/or rounded (Burns & Fay 1970). 



Burns & Fay (1970) used this feature to aid in establishing the systematic relationships 

 of the phocines, and of the genera Histriophoca, Pagophilus, Phoca (all state 0), and Pusa 

 (state 1) in particular. During our observations, we noted that some specimens displayed 

 an intermediate morphology that could not be unequivocally assigned to either of the two 

 extreme states. These specimens were coded as being polymorphic for this character. 

 A tapered or rounded premaxillary margin is primitive within the Caniformia, being found 

 in virtually all outgroup taxa (Lutra displays the intermediate condition). The apomorphic 

 state 0 occurs only within the phocids, but with independent origins in each subfamily. In 

 the phocines, this state characterizes the subfamily ancestrally and is retained by all 

 members, including Pusa spp. For the monachines, this state is limited to the clade 

 composed of Lobodon, Monachus spp., and Ommatophoca, with Lobodon and Monachus 

 monachus independently deriving the intermediate condition. 



4) triangular lateral extensions of premaxilla into maxilla in dorsal view: 0 = absent; 1 = 

 rudimentary or present (pers. obs.) (Fig. 18). 



In recording data for the previous character, we noted an unusual morphology for the 

 premaxilla in a number of specimens. In most cases, the premaxilla is bounded laterally 

 for most of its length by the maxilla when viewed dorsally, with the two bones meeting 

 along a smooth curve. However, the anteromost portion of the premaxilla occasionally 

 extends laterally as a small right triangle. This extension is not bounded laterally by the 

 maxilla and its roughly right-angled posterior edge disrupts the smooth curve mentioned 

 above. Although occurring sporadically in a wide range of species, this apomorphic 

 condition only appears consistently in Monachus schauinslandi and Monachus tropicalis, 

 with the polymorphic taxa Enhydra and Ursus apparently being in the process of 

 independently acquiring this trait. 



5) visibility of ventral portion of nasal processes of premaxilla along maxilla in lateral 

 view: 0 = always visible; 1 = not always visible (Wyss 1988a). 



As employed by Wyss (1988a), this character was used in conjunction with the next two 

 (characters #6 and 7) to describe the visibility of the nasal processes as a whole. The 

 condition in which the nasal processes were not always visible was felt to be a potential 

 synapomorphy of the monachines among the carnivores, if not most mammals (de 

 Muizon & Hendey 1980; de Muizon 1982a; Wyss 1988a). However, numerous exceptions 

 to this have been noted, with Histriophoca and Pagophilus approaching, and Monachus 

 tropicalis not displaying, this apparent monachine condition (de Muizon & Hendey 1980; 

 de Muizon 1982a; Wyss 1988a) 



We felt that the above coding was overly restrictive, with the possibility of creating a fair 

 degree of homoplasy as those species sharing the general condition "nasal processes not 



