91 



to a broad contact, with Phoca vitulina being uniquely characterized among this group by 

 a polymorphic reduced contact (states 0 or 1). 



12) length of nasal processes of premaxilla along maxilla: 0 = extend only part way to 

 nasals; 1 = extend fully or virtually fully to nasals (pers. obs.). 



The over-reaching effects of this character on all others dealing with the nasal processes 

 of the premaxilla have already been outlined. In association with the previous character, 

 any reduction m contact between the nasal processes and the nasals is held to be 

 apomorphic (de Muizon & Hendey 1980; Wozencraft 1989). However, the important factor 

 here is not the degree of contact between the two, but the degree of extension of the nasal 

 processes. Thus, we consider the situation where the nasal processes do extend to the 

 nasals but fail to contact them (e.g., due to a thin interposing sliver of the maxilla as in 

 Halichoerus or Phoca vitulina) as a trivial variation of full extension. Therefore, the 

 apomorphic condition is obtained only in the genera Cystophora, Mirounga, and 

 Ommatophoca. It is synapomorphic only for the two elephant seals. 

 For Cystophora and Mirounga, the apomorphic condition is likely associated with the 

 convergent morphological changes occurring around the nasal region to allow expansion 

 of the narial opening for extrusion of the inflatable nasal sac (King 1972; Reeves & Ling 

 1981; Kovacs & Lavigne 1986). Its parallel appearance in Ommatophoca is problematic. 

 Although this species is comparatively poorly described, no inflatable nasal appendage 

 has ever been reported for it. However, it should be noted that the nasal processes of 

 Ommatophoca do extend much further than they do in either Cystophora or Mirounga. 

 The apomorphic condition might be expected more for Halichoerus, a species with a nasal 

 region very similar in morphology to Cystophora and Mirounga (King 1972; Reeves & 

 Ling 1981). The similarity is so great that it is often felt that Halichoerus should possess 

 a nasal appendage to account for it (King 1972). 



13) shape of anterior margin of nasals (ignoring contribution of nasal suture): 0 = flat or 

 broadly indented; 1 = lobular (uni-, bi-, or tri- lobed) (pers. obs.). 



Although many authors have commented on various aspects of the morphology of the 

 nasal bones, including their general shape at the anterior end (e.g., Chapskii 1955a; King 

 1972; Reeves & Ling 1981; Kovacs & Lavigne 1986), very few have examined the 

 potential systematic usefulness of the nasal bones. Our observations revealed two major 

 groups with respect to the shape of the anterior end of the nasals: those with a simple, 

 roughly flat outline, and those with a more complicated lobular appearance. Of these two 

 nasal types, the plesiomorphic lobular condition is distributed throughout the Caniformia, 

 with the apomorphic flattened state represented only among the otarioids. 

 Unfortunately, this may be a consequence of the oversimplification of the coding scheme 

 we adopted. As is immediately obvious, the lobular condition encompasses three distinct 

 morphologies [see Fig. 7 in King (1956:230)] and numerous derivations thereof. As we 

 found no easy way to homologize these derivations with the major types, we were forced 

 to condense all these forms into the lobular morphology. However, it should be noted that 

 the caniforms nearly universally share a trident-like morphology, consisting of two lateral 

 prongs and a broader medial one. We suggest that this is, in fact, the plesiomorphic 

 condition, with the remaining lobular morphologies being derivations thereof (see the 

 following character). 



