153 



monachines less the polymorphic Mirounga spp. (DELTRAN optimization). Note, 

 however, that this slight discrepancy may hinge on our definition of this character being 

 different from the one intended by King (1966) and Wyss (1988a). 



165) cross-sectional shape of phalanges: 0 = flat; 1 = intermediate; 2 - round (King 1966; 

 Wyss 1988a). 



The second of Wyss's (1988a) metacarpal features examined the cross-sectional shape of 

 the phalanges. In the monachines, as in the otarioids, the phalanges are distinctly flattened 

 as opposed to the more rounded morphology of the phocines (Howell 1928; King 1966; 

 Wyss 1988a). However, the phalanges of the phocines are still appreciably flatter than 

 those found in fissiped carnivores (Wyss 1988a), and hence should represent more of an 

 intermediate condition (state 1). 



Generally, any apomorphic flattening of the phalanges is limited to the pinnipeds. Strongly 

 flattened phalanges (state 0) arise on at least three main occasions: Zalophus, Phoca 

 vitulina plus Pusa spp. (the two reconstructions indicate a conflicting assortment of 

 independent origins and losses in this general region), and those monachines internal to 

 Leptonychotes, minus Monachus tropicalis (which regains rounded phalanges). No phocine 

 demonstrated slightly flattened phalanges (state 1). Instead the appearance of this 

 morphology was limited to Lutra and Mirounga leonina. 



166) morphology of proximal phalangeal articular surface: 0 = hinge-like; 1 = trochleated 

 (King 1966; Wyss 1988a). 



In most caniforms, the proximal articular surface of the phalanx is strongly trochleated to 

 accommodate the "palmar" ridge of the distal metacarpal head (see character #164). The 

 lack of such a ridge in otarioids and monachines results in a more hinge-like articular 

 surface of the phalanx (King 1966; Wyss 1988a). As with the palmar ridges, Wyss (1988a) 

 interprets this distribution so that a hinge-like articulation is synapomorphic for the 

 pinnipeds, with the phocines reversing to re-obtain the primitive carnivore pattern. While 

 the same distribution of states was observed here, such an interpretation is contingent upon 

 the optimization criterion employed. Wyss's (1988a) scenario is applicable under 

 ACCTRAN optimization, but under DELTRAN optimization, hinge-like articular surfaces 

 are independently obtained in otarioids and monachines. 



167) comparative length of metacarpals I and II: 0 = I > II; 1=1 subequal to II; 2 = I 

 < II (King 1966; Wyss 1988a). 



Both King (1966) and Wyss (1988a) observed that in phocine seals, as in most carnivores, 

 metacarpals I and II are of approximately equal size. In contrast, the remaining pinnipeds 

 are characterized by an elongated and comparatively thicker first metacarpal (King 1966; 

 Wyss 1988a). This is a generalization, however, as Cystophora and Halichoerus are 

 approximately intermediate between these extremes (see King 1966: 391). Again, Wyss 

 (1988a) interprets this distribution to indicate a reversal, albeit incomplete (as the first 

 metacarpal is slightly longer than the second in phocines, while the situation is reversed 

 in fissiped carnivores), on the part of the phocines. We divided the original character 

 (relative metacarpal size) into its two component parts: relative metacarpal length and 

 relative metacarpal diameter (= robustness or thickness). As well, we have expanded the 



