136 



throughout by a bilobed morphology (albeit polymorphically with states 0 and/or 1 in 

 many species). A unilobular suture is independently regained in Pusa hispida (possibly as 

 a synapomorphy with Pusa sibirica; ACCTRAN optimization) and the clade of Monachus 

 schauinslandi plus Monachus tropicalis. The trilobed condition occurs uniquely for the 

 clade of Histriophoca plus Pagophilus. 



*124) separate temporal ridges: 0 = widely spaced; 1 = approximately in midline; 9 = 

 absent (pers. obs.). 



During our observations, we noted that in place of a sagittal crest, many specimens 

 possessed distinct paired ridges on either side of the midline. However, this character more 

 properly belongs with characters of the sagittal crest, as separate temporal ridges merely 

 represent incipient crests (Doutt 1942; King 1972). As well, the distance between the ridges 

 appears to be an age-dependent feature (and therefore of questionable systematic value), 

 with the ridges converging on the dorsal midline with increasing age (Doutt 1942). Thus, 

 with recoding, this character was included in character #126. 

 * 1 25) sagittal crest: 0 = absent; 1 = present (Ridgway 1972). 

 With recoding, this character was included in character #126. 



126) size of sagittal crest: 0 = absent, but separate temporal ridges present; 1 = small; 2 

 = medium; 3 = large; 9 = absent (Ridgway 1972; pers. obs.). 



The sagittal crest is a notoriously labile feature, being subject to both age variation and 

 sexual dimorphism. We tried to minimize the latter problem by scoring a species as 

 possessing a sagittal crest if a crest was consistently present in either sex. The development 

 of sagittal crests in very old individuals from the convergence of the separate temporal 

 ridges has been noted by both Doutt (1942) and King (1972). This potential problem was 

 minimized by examining only adult individuals. 



Although reasonably common throughout most of the Carnivora, there are conflicting 

 reports of the manifestation of sagittal crests among the phocids. Ridgway (1972) only 

 mentions distinct crests for Hydrurga and Leptonychotes, to which Ray (1976b) would 

 apparently add Mirounga spp. and Phoca vitulina (also Chapskii 1955a). However, de 

 Muizon & Hendey (1980) indicate reduced crests in Leptonychotes and Lobodon. King 

 (1972) claims crests of various sizes (but typically small) for all phocids except the three 

 smallest genera (Histriophoca, Pagophilus, and Pusa) which possess widely spaced 

 temporal ridges. Halichoerus apparently develops a strong crest with old age (Chapskii 

 1955a), as does Monachus tropicalis (Allen 1887). 



This study indicates that sagittal crests are possessed primitively within the Caniformia, 

 before being reduced to separate temporal ridges in going to the pinnipeds. Canis is 

 unusual in possessing a large sagittal crest (only found elsewhere in Zalophus), with the 

 sagittal crests typically being small in fissiped caniforms. Separate temporal ridges arise 

 as a synapomorphy of the pinnipeds (and possibly Lutra as well; ACCTRAN optimiza- 

 tion), with a convergent appearance in Procyon. Within the phocids, the trend is towards 

 the loss of even this feature. This is limited in the phocines (Erignathus and Pusa sibirica 

 only), but more widespread in the monachines, diagnosing Mirounga angustirostris and 

 the clade of Lobodon, Monachus spp., and Ommatophoca. However, small sagittal crests 



