714 
Fishery Bulletin 96(4), 1998 
The third lineage of Pleuronectini is a clade unit- 
ing Platichthys, Pleuronectes, and Pseudopleuro- 
nectes. This result was observed in 80 of 128 ( 62.5%) 
trees found by heuristic search and is supported by 
four morphologies (Fig. 17): bony prominences on 
blind-side postocular ridge (102, Fig. 10E); a strong 
medial curvature on fifth ceratobranchial resulting 
in close approximation or union of ceratobranchials 
(71, Fig. 3D); an increase of rows of teeth on fifth 
ceratobranchial from two regular rows to multiple 
rows of regular length (49, Fig. 3D); and anterior 
margin of mesethmoid (53) either a thin plate (Fig. 
8B) or thickened triangular edge (Fig. 80. 
Exceptions and homoplasy observed in these mor- 
phological characters contributed to three alterna- 
tive topologies for intrarelationships of Pleuronectini 
(Fig. 18, A-C). Bony prominences on the blind-side 
postocular ridge were not observed in Pseudo- 
pleuronectes, Pleuronectes platessus, and P. quadritu- 
berculatus and are homoplastic in Limanda probo- 
scideo and L. punctatissima. Both attributes of the 
fifth ceratobranchial, the close approximation of the 
medial margins and the multiple rows of teeth, are 
not observed in Pseudopleuronectes . The thin plate 
structure of the mesethmoid (Fig. 8B), observed in 
Pseudopleuronectes and Pleuronectes platessus is 
homoplastic in Dexistes rikuzenius, Pleuronichthys 
verticalis (Microstomini), and Hippoglossoides 
(Hippoglossoidinae). The thickened triangular edge 
of the mesethmoid (Fig. 80 is unique within 
