Cooper and Chapleau: Monophyly and intrarelationships of the family Pleuronectidae 
699 
(Hippoglossinae). The pterosphenoid and prootic do not 
unite to form the dorsal margin of the anterior prootic 
foramen (Fig. 7A) in the following pleuronectine spe- 
cies: Glyptocephalus cynoglossus, G. stelleri, G. zachirus, 
Limanda ferruginea, L. proboscidea, L. punctatissima, 
Platichthys stellatus, Pleuronichthys guttulatus, and 
Pseudopleuronectes americanus. Verasper variegatus, 
not classified in this second lineage, has the dorsal 
margin of this foramen formed by the pterosphenoid 
and prootic on both ocular and blind side. The first 
epibranchial is bifurcated in the pleuronectine species 
Dexistes rikuzenius, Limanda aspera, L. limanda , L. 
sakhalinensis, Glyptocephalus , Microstomus, and 
Pleuronichthys. Both species of Verasper were observed 
to have a bifurcated first epibranchial. The pattern of 
these exceptions is similar in these two characters, but 
the analysis did not indicate an alternative topology 
that would exclude any of the previously mentioned 
species, or include Verasper within the second lineage. 
The pattern does suggest that these exceptions are in- 
stances of reversal or convergence and may determine 
phylogeny within these other groups. 
The third pleuronectid lineage (III) indicates a com- 
mon ancestor for Lyopsettinae, Hippoglossoidinae, 
