159 



monachines as well as Lobodon (de Muizon & Hendey 1980; de Muizon 1982a). A similar 

 absence of the fossa in the otarioids, combined with its presence throughout the rest of 

 the Carnivora led Wyss (1988a) to suggest that this character indicated yet another reversal 

 on the part of the phocines. In contrast, de Muizon (1982a) held the monachine pattern 

 to be apomorphic for the subfamily. 



A deep trochanteric fossa is plesiomorphic among the Caniformia, being found in all major 

 fissiped lineages. The above distribution for this character is largely borne out (with the 

 exception of a' shallow fossa in Zalophus, Leptonychotes, and Monachus monachus), but 

 the evolutionary pathway is dependent on the reconstruction technique employed. 

 DELTRAN optimization largely supports de Muizon (1982a), with the plesiomorphic 

 condition being retained by the phocines, and parallel losses or reductions of the fossa 

 occurring in the otarioids and monachines. In contrast, ACCTRAN optimization supports 

 Wyss (1988a), in that the loss of the foramen is synapomorphic for the pinnipeds, with 

 the phocines re-deriving a deep fossa. As expected, Lobodon regains a medium depth 

 fossa. 



181) lesser trochanter: 0 = absent; 1 = present (de Muizon 1982a). 



The phocids are unique among mammals in lacking the lesser trochanter on the femur 

 (Howell 1928; de Muizon 1982a). A slight discrepancy exists as to the resulting new 

 insertion point of the psoas magnus. The majority opinion is that the insertion shifts to 

 the posteroventral ischiatic spine (= pectineal tuberosity) on the ventral edge of the ilium, 

 representing an adaptation to enhance the lateral undulatory movements employed in the 

 phocid swimming style (Miller 1887; Bryden 1971; Pierard 1971; de Muizon & Hendey 

 1980; de Muizon 1981, 1982a). However. Howell (1928) indicates this to be a different 

 muscle, the psoas tertius, and places the insertion of the psoas magnus on the medial 

 tuberosity of tibia, together with the iliacus. In any case, the apomorphic loss of the lesser 

 trochanter for the phocids is indicated here. 



182) relative width of femur distally: 0 = gracile (less than medium breath); 1 = robust 

 (greater than or equal to medium breadth) (M.A. Cozzuol pers. comm.). 



In conjunction with his research into the possible paraphyletic nature of Monachus spp., 

 M.A. Cozzuol kindly pointed out this character to us. He noted that the femur is very 

 robust and broad distally in M. monachus, but much more gracile in M. schauinslandi and 

 M. tropicalis. Additionally, de Muizon & Hendey (1980) hint at a wide distal end to the 

 femur in the lobodontines. In applying this character to the other taxa in this study, a 

 comparatively robust femur appears to be a synapomorphy of the monachines, missing 

 only in Mirounga leonina and the clade of Monachus schauinslandi and M. tropicalis 

 (ACCTRAN optimization). However, another possibility holds for independent origins of 

 a wide distal end in Mirounga angustirostris and most of the remaining monachines 

 (DELTRAN optimization). 



183) proximal fusion of tibia and fibula: 0 = unfused; 1 = rudimentary - not fused all the 

 way around; 2 = totally fused (Wyss 1988a). 



The fusion of the proximal epiphysial heads of the pinniped tibia and fibula presumably 

 represents an adaptation to strengthen and decrease the mobility of this region of the leg 



