9 



135 



state to be a synapomorphy of the phocines, before a reversal back to the vertical 

 morphology occurs internal to Halichoerus. Independent origins of the sail shape in 

 Monachus schauin slandi and in each of the two pusids account for the remaining 

 appearances of this state under this latter scenario. The inverse sail morphology never 

 appeared consistently at the species level, being observed only as a polymorphism with 

 state 2 in Histriophoca and Ommatophoca. 



122) partial bony falx: 0 = absent; 1 = present (Nojima 1990; pers. obs.). 



The partial bony falx is a small projection originating from the anterodorsal junction of 

 the two halves of the bony tentorium. Although it and the bony falx proper are apparently 

 mutually exclusive (Nojima 1990), we have occasionally noted the simultaneous presence 

 of these two structures. It may be that the partial bony falx indicates the former or future 

 presence of an inverse sail-shaped bony falx, a morphology that was never consistently 

 observed for any species (see previous character). The two structures possess similar 

 orientations and were never observed coincidentally. In any case, we list the partial bony 

 falx as a character separate from the morphology of the bony falx proper. As noted before, 

 Nojima (1990) lists this feature as occurring only in Ursus. 



Our analysis indicates that the partial bony falx is actually a primitive feature within the 

 Caniformia. It is found in Canis and Ursus (both of which lack a bony falx proper), before 

 becoming lost in the remaining caniforms (although Enhydra and Erignathus are 

 polymorphic for this trait). 



Dorsal braincase (4 characters) 

 In carnivores, this region is largely devoid of phylogenetically informative features due 

 to it being almost completely covered by the enlarged temporalis muscle (Davis 1964). 

 Understandably then, most of the few useful characters are associated with this muscle in 

 some manner. 



123) shape of fronto-parietal suture: 0 = flat; 1 = unilobe; 2 = bilobed; 3 = trilobed or 

 greater (Burns & Fay 1970). 



The fronto-parietal suture is often more than just a simple flat suture. In Histriophoca and 

 Pagophilus, the suture is usually trilobed, while in Phoca and Pusa it is bilobed (Burns & 

 Fay 1970). We also noted an additional, unilobular morphology in many species. However, 

 this character is not as straightforward as it would first appear, as the suture rarely appears 

 as a clear-cut example of one of the states listed above. Very often, the lobes are compacted 

 together, and an arbitrary judgment must be made as to what constitutes a main lobe as 

 opposed to an accessory lobe of the main one. As well, individual specimens of Hydrurga 

 and Ommatophoca confounded this problem still further by having an open anterior 

 fontanelle, something that is apparently quite common in adult Ommatophoca (King 1969, 

 1972, 1983; Ray 1976b). The systematic value of this character is limited still further by 

 the high amount of intraspecific polymorphism. 



Despite these numerous problems, a reasonably clear pattern emerged from this character. 

 A flat suture is plesiomorphic, with a unilobular suture diagnosing the mustelids (including 

 the lutrines) plus the pinnipeds. Zalophus reverses to the plesiomorphic condition. A 

 multilobed suture is peculiar to the phocids, which are united ancestrally and generally 



