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Fishery Bulletin 96(4), 1998 
Engyprosopon, Tosarhombus, Crossorhombus, 
and Bothus [Amaoka, 1969]). 
2 Ocular-side preorbital sensory canal absent, with 
exceptions only in Reinhardtius hippoglossoides 
and Acanthopsetta nadeshnyi. In the bothoid 
group, as well as in the Citharidae and Psetto- 
didae, this sensory canal is present (Amaoka, 
1969). 
3 Ventral margin of metapterygoid flattened (Fig. 
2, B-D), with exception in Reinhardtius stomias, 
which has a distinct curvature along the ventral 
margin of this bone. Outgroup taxa also possess 
this ventral curvature of the metapterygoid (Fig. 
2A). 
4 First and second basibranchials loosely joined by 
cartilage with exceptions observed in Eopsetta 
grigorjewi, Isopsetta isolepis, Limanda ferruginea, 
L. punctatissima, Parophrys vetula, Psettichthys 
melanostictus, and Reinhardtius stomias in which 
basibranchials are sutured. Outgroup taxa also 
have a suture between first and second basibran- 
chials (Fig. 3A). 
5 Second and third basibranchial loosely joined by 
cartilage (Fig. 3, B-D) with exceptions in 
Limanda punctatissima and Psettichthys melano- 
stictus. Outgroup taxa have a suture between sec- 
ond and third basibranchials (Fig. 3A). 
6 Posteriormost abdominal vertebrae lack haema- 
pophysis (Fig. 40, with exceptions in Eopsetta 
grigorjewi , Microstomus achne, M. kitt, M. 
pacificus, and Reinhardtius stomias in which 
haemapophysis are present (Fig. 4D). Outgroups 
have fused parapophysis forming a haemal arch 
on the posteriormost abdominal vertebrae (Fig. 
4, A and B). 
7 Accessory processes on caudal vertebrae absent 
(Fig. 5, B and C), with exceptions in Hippoglossus 
hippoglossus, H. stenolepis, Microstomus bathy- 
bius,Pleuronichthys decurrens , P . guttulatus , and 
P. ritteri. Outgroups have accessory processes on 
ventral surface of centrum for all caudal verte- 
brae (Fig. 5A). 
8 Ocular-side infraorbital bones present with ex- 
ception in Microstomus bathybius. Outgroup taxa, 
except Psettodes, do not have infraorbital bones 
on the ocular side. Psettodes has four infraorbital 
bones on the ocular side. Presence of infraorbital 
bones in Pleuronectidae, although not unique in 
comparison with all outgroup taxa, is likely a re- 
versal in the bothoid lineage and synapomorphic 
for the family. 
9 Oil globules in egg absent, with exceptions of one 
oil globule found in Pleuronichthys cornutus, P. 
guttulatus , and P. ritteri (Ahlstrom et al., 1984). 
Outgroups have at least one oil globule (Ahlstrom 
et ah, 1984). Distribution of this character was 
not confirmed in the specimens used for this 
analysis; however the source for this information 
(Ahlstrom et al., 1984) confirms this distribution 
in 46 of the 59 pleuronectid species. 
10 Olfactory laminae are parallel without a central 
rachis, with exception in Reinhardtius evermanni 
and R. stomias. As in the outgroup, species of 
Reinhardtius have laminae that radiate from a 
central rachis (Norman, 1934). Distribution of this 
structure was not confirmed in this analysis. His- 
torically, this structure has been used to diagnose 
the Pleuronectinae ( sensu Norman, 1934) and 
appears to be unique in flatfishes. There has not 
been any evidence to suggest that this occurs in 
any other flatfish species. 
Exceptions in distribution of these ten synap- 
omorphies do not have a common phylogenetic pat- 
tern and do not corroborate exclusion of any of the 
53 species examined in this analysis. The exceptions 
suggest independent cases of reversed characters 
(reversals) for either the species or their immediate 
ancestors, and these will be discussed in the context 
of species interrelationships within the Pleuro- 
nectidae. It is noted that Reinhardtius stomias has 
four exceptions to the ten synapomorphies in 
Pleuronectidae. The most parsimonious explanation 
places this species in the Hippoglossinae on the ba- 
sis of seven additional synapomorphies. Other char- 
acters (48, 77, 83, and 104) appear to be synapo- 
morphies for the Pleuronectidae. However, distribu- 
tion of these characters was examined in only the 53 
ingroup taxa and in the five outgroup taxa used for 
this analysis. This limited survey is not sufficient to 
provide a full understanding of the distribution of 
these character states within the order. Therefore 
these character states are not presented as synapo- 
morphies for the family and are only presented in a 
phylogenetic context within Pleuronectidae. Future 
analysis examining higher-level relationships within 
Pleuronectiformes should include these morphologi- 
cal characters. 
Intrarelationships of the Pleuronectidae 
The phylogenetic analysis reveals various monophyl- 
etic lineages within the Pleuronectidae, four of which 
illustrate the interrelationships of five newly defined 
subfamilies: Hippoglossinae, Eopsettinae, Lyopset- 
tinae, Hippoglossoidinae, and Pleuronectinae (Fig. 
6). These subfamilies are separated by a gradation 
of characters (11 to 22) such that the first three, 
Hippoglossinae, Eopsettinae, and Lyopsettinae, con- 
tain species with a large proportion of plesiomorphic 
