RICHARDS AND LEIS: LABROIDEI 



547 



ferent. A cursory study indicates larvae of these latter families 

 share at least four derived characters: almost total lack of head 

 spination; a long, rugose, straight gut which loops relatively late 

 in development; compressed, elongate body; and a reduction in 

 principal caudal ray number from the typical percoid comple- 

 ment of 9 + 8. The "percoid" larval type of the pomacentrids 

 and cichlids might be a primitive character state, but there are 

 no derived characters which unite their larvae with the labrid 

 type of larvae. At least gut development and head spination of 

 the labrids are shared with the pseudochromids, which are gen- 

 erally very similar to some labrid larvae which settle at small 

 sizes (Leis and Rennis, 1983). This may be the result of con- 

 vergence, but a labrid/pseudochromid relationship should be 

 investigated as an alternative to Kaufman and Liem's (1982) 

 proposed phylogeny. 



If Kaufman and Liem (1982) are correct in proposing the 

 pomacentrids as the primitive sister group of the other labroids, 

 then either parental care of hatched young evolved indepen- 

 dently in the pomacentrid Acanihochromis and the cichlids (vi- 

 viparity in embiotocids might be a derivation of parental care 

 of eggs and hatched larvae, but this remains to be shown), or 

 was present in a pre-pomacentrid common ancestor and was 

 secondarily lost in all labroids but the cichlids and Acaniho- 

 chromis. Similarly, either demersal eggs and parental care of 

 them evolved independently in some labrids, pomacentrids, and 

 cichlids. or were present in a pre-pomacentrid common ancestor 

 and secondanly lost in most labrids and all scarids and odacids. 

 Therefore, neither demersal eggs nor parental care of hatched 

 young offer much support to Kaufman and Liem's (1982) phy- 

 logeny. 



ELH characters may be useful in studying the intrafamilial 

 relationships of labroid fishes. Larval labrids are very diverse 

 in development and morphology, and this may prove useful in 

 elucidating labrid interrelationships. Within the labrids, de- 

 mersal eggs and parental care of eggs are unique to some mem- 

 bers of the tribe Labrini. Egg shape and larval morphology sup- 

 port the subfamilial divisions within the Scaridae. Too little is 

 known of pomacentrid and cichlid development to say if ELH 

 characters might be useful in elucidating intrafamilial relation- 

 ships. 



In conclusion, ELH characters support Kaufman and Liem's 

 (1982) labroid phylogeny only in the close relationship of the 

 labrids, scarids, and odacids. In spite of the similarities uniting 

 the three families, there are enough differences between their 

 known larvae to lead us to suggest the labrids, scarids, and 

 odacids should not be combined into one family at this time. 

 M. F. Gomon (pers. comm.) argues that the alternative to com- 

 bining the three families into one is splitting the group into as 

 many as five smaller families. While we do not advocate this 

 course, the great larval diversity found within the group could 

 provide evidence supporting this alternative. However. ELH 

 information for more genera of labrids, scarids, and odacids 

 must be gathered before firm statements can be made. 



(W.J.R.) National Marine Fisheries Service, Southeast 

 Fisheries Center, 75 Virginia Beach Drive, Miami, 

 Florida 33149; (J.M.L.) The Australian Museum, 6-8 

 College Street, Sydney 2000, Australia. 



Acanthuroidei: Development and Relationships 

 J. M. Leis and W. J. Richards 



THE acanthuroid fishes are marine, tropical and, except for 

 the pelagic Luvaridae, are associated with coral reefs. The 

 suborder consists of about 1 10 species distributed among four 

 families: Acanthuridae (Randall, 1955a), Luvaridae (Roule, 

 1924; Tyler, Nakamura and Collette, MS in prep.). Siganidae 

 (Woodland, 1983), and Zanclidae (we follow Randall, 1981, and 

 consider the Zanclidae distinct from the Acanthuridae). Ap- 

 parently, all species have a specialized pelagic stage between 

 larvae and juveniles, often referred to as an acronurus larval 

 stage (we prefer to restrict this term to its original usage in the 



Acanthuridae). This specialized pelagic stage has provided the 

 basis for the description for many supposedly new species and 

 genera, and has been used as evidence for uniting the group 

 (e.g., Lauder and Liem, 1 983). The siganids are usually consid- 

 ered the most generalized (=primitive) family of the suborder, 

 and the zanclids are considered closely related to if not included 

 in the acanthurids (Tyler, 1 970). Luvanis has recently been shown 

 to be closely related to the acanthurids (Tyler, Nakamura and 

 Collette, MS in prep.). The chaetodontids have been suggested 

 as the percoid group from which acanthuroids were derived 



Table 132. Meristic Characters of Acanthuroid Fishes. N is the number of recent species, principally after Nelson, 1976. Note that in the 

 Luvandae there is a progressive loss offin rays from the larval stage (adult counts in parentheses). Maximum larval counts are followed by adult 

 counts in parentheses. (Data from Randall. 1955b. c: Smith. 1966a; Weber and de Beaufort. 1936; Gregory and Conrad. 1943; and Leis and 



Rennis. 1983). 



