158 



shift of the ischiatic spine in males. However, in noting the fairly consistent anterior shift 

 of the spine throughout the pinnipeds here (in conjunction with our attempts to have an 

 equal representation of males and females), we judge the effect of this potential error to 

 be minimal. 



Hind Limb (12 characters) 

 Certain features of the hind limb have been useful in defining the phocids as a family 

 (e.g., lack of a lesser trochanter on the femur, presence of posterior process on the 

 astragalus) (Howell 1928; de Muizon 1982a), but otherwise, the hind limb (exclusive of 

 the pelvis) has not been used to a great extent to elucidate phocid phylogeny. This might 

 be explained for the femur, at least, by it being assigned a generally low diagnostic value 

 due to its high variability (e.g., Ray 1976a; de Muizon & Hendey 1980). 

 178) position of greater trochanter on femur: 0 = lower than head; 1 = equal with head; 

 2 = higher than head (King 1966; de Muizon 1982a). 



This character has been briefly mentioned to define either of the phocid subfamilies. King 

 (1966) notes that phocines tend to possess state 2, while de Muizon (1982a) used state 0 

 to define a synapomorphy of the monachines, a distribution echoed by de Muizon & 

 Hendey (1980). Here, the morphologies whereby the greater trochanter is equal to or higher 

 than the femoral head are apomorphic. State 1 characterizes the phocines ancestrally and 

 is universal within the subfamily except for Pagophilus, Phoca largha, and Pusa sibirica, 

 which independently derive state 2. State 1 also appears in the monachine Monachus tro- 

 picalis (possibly as a synapomorphy with Monachus schauinslandi; ACCTRAN optimi- 

 zation) and the fissipeds Enhydra, Martes, and possibly Procyon, either by convergence 

 (DELTRAN optimization), or as a synapomorphy of the fissiped taxa, with a reversal to 

 the primitive caniform condition in Lutra plus the pinnipeds (ACCTRAN optimization). 

 The slight discrepancy with previous observations (phocines generally possessing state 1 

 and not state 2) can be related to the fact that our observations of this character were made 

 so that the distal condylar surfaces of the femur were level. However, the autapomorphic 

 development of an epicondylar ridge in phocids causes the distal condylar surfaces to be 

 slightly oblique with respect to the femoral shaft (de Muizon 1982a). Thus, with our 

 technique, the greater trochanter would be shifted to a lower position relative to the femoral 

 head. That this character still indicates a synapomorphy of the phocines speaks for the 

 height to which the greater trochanter is raised in this group. 



* 1 79) distinct trochanteric fossa on femur: 0 = absent; 1 = present (King 1966; de Muizon 

 1982a). 



With recoding, this character was included in character #180. 



180) depth of trochanteric fossa on femur: 0 = shallow; 1 = medium; 2 = deep; 9 = absent 

 (King 1966; de Muizon 1982a). 



As compared to the modern monachines, another distinguishing feature of the phocine 

 femur is the development of a distinct trochanteric fossa (King 1966; de Muizon 1982a). 

 However, the value of this character may be limited by its inconsistent presence in 

 phocines (e.g., it is absent in Erignathus) together with its presence in many fossil 



