125 



94) relationship between paroccipital processes and nuchal (= lambdoidal) crest: 0 = 

 separate; 1 = adjacent / continuous: 9 = n/a - paroccipital processes absent (Hendey & 

 Repenning 1972). 



Hendey & Repenning (1972) note the tendency of the nuchal crest to become confluent 

 with the enlarged paroccipital processes in Monachus schauinslandi and Monachus 

 tropicalis. However, at best, this apomorphic feature only arose independently as 

 polymorphisms for Monachus monachus and M. tropicalis, although we noted it in isolated 

 specimens of Lobodon, Mirounga leonina, and Monachus schauinslandi. Again, processes 

 were consistently absent in Pusa caspica, and polymorphically so in Pusa sibirica. 



95) relative size and shape of posterior lacerate foramen: 0 = not confluent with 

 petrobasilar fissure: 1 = confluent with petrobasilar fissure; 9 = petrobasilar fissure absent 

 (Wyss 1988a). 



In most mammals, the posterior lacerate foramen is roughly circular and restricted to an 

 area posteromedial to the auditor}' bulla. As well, in carnivores, the fissure between the 

 auditory bulla and both the basioccipital and basisphenoid, the petrobasilar fissure, 

 typically disappears during development (Wyss 1988a). However, the phocines, exclusive 

 of Erignathus, are peculiar in that the posterior lacerate foramen expands anteromedially 

 to become confluent with the patent petrobasilar fissure (King 1966; Wyss 1988a). We 

 observed that most of the taxa examined here possess at least a crack between the 

 basioccipital and basisphenoid bones and the bulla (see also character #96). Although not 

 a true fissure, we have equated this crack with a reduced petrobasilar fissure. Thus, the 

 state identified by King (1966) and Wyss (1988a) for the phocines is due to the confluence 

 of both an expanded posterior lacerate foramen and an expanded (rather than patent) 

 petrobasilar fissure. 



This slight difference in interpretation accounts for state 1 being the most common state 

 here, and primitive at the level of the Arctoidea (the case for the caniforms being 

 equivocal). [The analogous state as defined by King (1966) and Wyss (1988a) was 

 restricted to the phocines minus Erignathus.] The converse situation, where the posterior 

 lacerate foramen and petrobasilar fissure are not confluent, is a synapomorphy of the 

 monachines. State 9 was independently obtained for Martes and Erignathus. due to then- 

 parallel outright loss of the petrobasilar fissure [as described by Burns & Fay (1970) for 

 Erignathus]. 



96) relationship between petrobasilar fissure and basioccipital-basisphenoid suture: 0 = in 

 contact, suture unexpanded; 1 = in contact, suture greatly expanded and confluent with 

 fissure; 9 = petrobasilar fissure absent (pers. obs.). 



As in the previous character, this character attempts to summarize some of the bone loss 

 occurring in the ventral basicranial region of phocids. In the phocines. numerous 

 perforations are present in this region, most of which display high intraspecific variability 

 (Burns & Fay 1970; King 1972). One of the few features that we observed consistently 

 at the species level is of a medial expansion of the basioccipital-basisphenoid suture away 

 from the auditory bulla. In most cases, this expanded suture was confluent with the 

 expanded petrobasilar fissure, resulting in a great deal of bone loss in the basicranial area. 

 As hinted at by King (1966), this apomorphic condition (state 1) is found only in Pusa 



