98 



28) size of nasolacrimal foramen: 0 = small; 1 = medium or greater; 9 = absent (Wozencraft 

 1989; pers. obs.). 



Among carnivores, the tendency towards the loss of the nasolacrimal foramen may be a 

 synapomorphy of a monophyletic Pinnipedia. The foramen is truly lacking only among 

 phocids, being vestigial in the otariids and often absent in old individuals (King 1983; 

 Wyss 1987; Wozencraft 1989). A gradual loss of the nasolacrimal foramen is indicated 

 here. Primitively, the Caniformia are characterized by a medium-sized foramen (Canis and 

 Ursus). The foramen either becomes reduced in size for most of the remaining fissiped 

 outgroups (ACCTRAN optimization), or is retained at medium size with some independent 

 derivations of a small foramen (DELTRAN optimization), before becoming lost in the 

 hypothetical pinniped ancestor. The vestigial nature of the foramen noted above by 

 Wozencraft (1989) is not seen in our representative otariid; however, the outright lack of 

 the foramen we observed in Zalophus might be artifactual, reflecting the fact that only 

 adult specimens were examined in this study, or that Zalophus might not be a typical 

 otariid in this respect. A vestigial foramen is indicated more in Odobenus, which is 

 polymorphic for this character (states 1 and 9). 



29) location of inferior oblique muscle origin relative to nasolacrimal foramen: 0 = widely 

 separate; 1 = closely adjacent (Wozencraft 1989). 



The inferior oblique muscle originates on the skull in the region of the lacrimal bone. The 

 potential fossa denoting this origin, the fossa muscularis, is well developed only in ursids 

 and the pandas, Ailuropoda and Ailurus, and is completely absent in procyonids and canids 

 (Davis 1964). Our observations indicate that the fossa is also apparently lacking in the 

 pinnipeds, mustelines, and lutrines. Thus, with no reliable indicator for the site of origin, 

 we relied on the data in Wozencraft (1989) for this character. Unfortunately, this character 

 is of limited use here as the closely adjacent morphology is autapomorphic for ursids. 

 Examining for the presence of the fossa muscularis may not be any more informative, as 

 our observations indicate that the presence of the fossa is again autapomorphic for ursids. 



30) lacrimal: 0 = absent / not visible; 1 = visible (King 1971; pers. obs.). 



The apparent loss of the lacrimal bone has been described for the pinnipeds on a number 

 of occasions (Howell 1928; King 1971, 1983). This loss has been ascribed either to its 

 outright loss, to a posterior displacement and a failure to ossify (Howell 1928), or, more 

 likely, to its fusion with the maxilla during development (King 1971, 1983). In the 

 otarioids, this fusion is age-dependent, with younger animals often displaying a lacrimal 

 (King 1971). No separate lacrimal bone has ever been conclusively reported on a phocid 

 skull of any age (King 1983). The only suspected case involves a tentative assessment for 

 a small unidentified bone fused to the maxilla in a Mirounga leonina fetus [Kummer & 

 Neiss 1957 (as cited in Wyss 1987)]. [At one point in our observations, we thought that 

 we had observed the lacrimal in a Leptonychotes skull; however, further examination 

 revealed that it was more likely a portion of the maxilloturbinal underlying the widened 

 maxillo-frontal suture (see Howell 1928; character #31).] An age-dependent fusion of the 

 lacrimal to the maxilla has also been noted for mustelines and lutrines (Wozencraft 1989). 

 The disappearance of the lacrimal is limited here to Martes, Enhydra (which is 

 polymorphic for this trait), and the pinnipeds. This apomorphic loss either arises 



