HENSLEY AND AHLSTROM: PLEURONECTIFORMES 



Table 179. Extended. 



675 



in these groups, they occur only as one pair on the anterior end 

 of the vertebra. In addition, the Cyclopsetta group has two pairs 

 of very small lateral protuberances on most vertebrae. How to 

 interpret the presence of vertebral transverse apophyses in pleu- 

 ronectiforms is still open to question. 



First neural spine.— Amaoka {1969) found that the neural spine 

 of the first vertebra is missing in the Bothidae and interpreted 

 this as a synapomorphy for the group, since absence of this spine 

 is apparently rare or unknown in other teleosts. We have made 

 a preliminary survey for this in other pieuronectiforms not treat- 

 ed by Amaoka. Some of this survey was based on radiographs, 

 and due to the close proximity of the first vertebra and neu- 

 rocranium, in some groups we are not sure if the first neural 

 spine is present, absent, or greatly reduced. The states in other 

 groups are more certain, since some cleared-and-stained ma- 

 terial was available. A greatly reduced or missing first neural 

 spine is not limited to the Bothidae (Table 1 79). 



Position of the urinary papilla. — AW flatfishes have a papilla on 

 the posteroventral area of the abdomen near the anal-fin origin. 

 Schmidt (1915, cited by Norman, 1 934) commented on its po- 

 sition in flatfishes, claiming it was located on the ocular side in 

 all species. However, Chabanaud (1934), Hubbs (1945), and 

 Hubbs and Hubbs (1945) found it to be on the midventral line 



in Psettodes. In addition, Hubbs (1945) and Hubbs and Hubbs 

 (1945) found the papilla on the blind side in the paralichthyid 

 genera Syacium, Citharichthys. and Etropus. We have found it 

 in the same position in Cyclopsetta. Another exception here 

 may be certain cynoglossids. Menon (1977: fig. 45) shows the 

 urinary papilla on the blind side in a species of Cynoglossus, 

 but claims it is attached to the first anal-fin ray in all species of 

 the family. A midventral position for the papilla is generalized 

 for teleosts and plesiomorphic for pieuronectiforms. 



Position o/" ve«?. — Position of the anus in flatfishes has been 

 reviewed by Norman (1934), Hubbs (1945), and Hubbs and 

 Hubbs (1945). A midventral position is plesiomorphic for the 

 order. In flatfishes where the vent is on or near the midventral 

 line, it is often very difficult to determine what state is repre- 

 sented. It is on the blind side in several groups, but apparently 

 on the ocular side only in the Citharidae. Hubbs (1945) inter- 

 preted the distribution of these states as indicating that deflec- 

 tion of the vent to the blind side has occurred several times 

 within the order. 



Caudal-fin complex.— The caudal fin and skeleton of many 

 species of pieuronectiforms have been illustrated and discussed 

 (e.g., Monod, 1968; Amaoka, 1969). The caudal skeleton of 

 Psettodes is reported to be the most primitive among living 



