Cooper and Chapleau: Monophyly and intrarelationships of the family Pleuronectidae 
701 
B 
Figure 7 
Lateral aspect of crania. (A) Hippoglossus hippoglossus , ARC 8808487; (B) Pleuronichthys 
cornutus, UMMZ 159618; (C) Limanda limanda, MNHN 1959-560. Left is ocular side; right is 
blind side, bo = basioccipital; eo = exoccipital; epo = epiotic; frb = frontal (blind side); fro = frontal 
(ocular side); ic = intercalar; ip = interorbital process; me = mesethmoid; pa = parietal; pfb = 
prefrontal (blind side); pro = prootic; ps = parasphenoid; pt = pterotic; pts = pterosphenoid; pv = 
prevomer; sp = sphenotic. Scale bars are 10 mm. 
exilis do not show this condition. This alternative 
hypothesis would require three evolutionary steps, 
one more than is presently hypothesized. An equivo- 
cal alternative (two steps) would require a single 
reversal in character 22 to define a monophyletic 
group of Eopsetta and Lyopsetta. However, this to- 
pology was not observed in any of the 128 most par- 
simonious trees. 
Subfamily Hippoglossinae The first pleuronectid 
lineage is classified as Hippoglossinae, with eight 
species (6 examined) in four genera: Clidoderma 
( incertae sedis), Hippoglossus, Reinhardtius, and 
Verasper (Fig. 11). This subfamily, as well as the 
intrarelationships of its species, were observed in all 
of the most parsimonious cladograms. The Hippo- 
glossinae are hypothesized to be monophyletic ac- 
