Genera of Acanthuridae — RANDALL 
361 
as highly specialized then as they are today. 
The fossil record of the Acanthuridae indi- 
cates that both Naso and Acanthurus date back 
to the Eocene (Agassiz, 1838; Woodward, 
1901 ; Eastman, 1917), thus these are among 
the specialized genera making the apparent 
sudden appearance in the early Tertiary. 
Hussakof (1907) recorded a fossil Zebra- 
soma (as Z. deani) from the West Indies. The 
specimen, which was well preserved, was con- 
sidered possibly of Eocene age. In my opinion 
this fish is not a Zebrasoma . It lacks the great 
depth of body and elevated fins of this genus. 
Also there is a very narrow caudal peduncle 
and a crescentic (high and narrow) caudal 
fin, and no caudal peduncle spines were lo- 
cated. Of existing genera, it seems closest to 
Naso. This specimen, which was deposited in 
the American Museum, should be re-exam- 
ined and its position within the Acanthuridae 
re-evaluated. 
Two extinct genera, Aulorhamphus de Zigno 
(Eocene) and Apostasella Whitley (new name 
for Apostasis Gorjanovic-Kramberger) (Oligo- 
cene-Miocene) have been included in the 
Acanthuridae although no caudal peduncle 
spines have been found for these forms. Ogil- 
by (1916: 173) views "with grave suspicion" 
the inclusion of these genera in the surgeon 
fish family. I concur in this doubt. 
The fossil Acanthurus gaudryi de Zigno and 
A. gazolae Massalongo were considered by 
Woodward (1901) and Eastman (190 4a) as 
not belonging to the genus Acanthurus . 
Woodward believed they might be better 
placed in the Chaetodontidae. Eastman 
thought them types of distinct genera, but 
preferred to include them in Pygaeus Agassiz, 
the limits of which were widely extended by 
Agassiz. In Jordan’s opinion (Eastman, 
1904£), Pygaeus is a generalized type ancestral 
to the Chaetodontidae, Acanthuridae, and 
Teuthididae (Siganidae). Berg (1947: 482) 
thought the VIII or IX anal spines of some 
Pygaeus allies it more closely with the latter 
than with the other two families. 
It is evident that more study of the fossil 
Acanthuridae and related families is needed, 
with especial effort to integrate knowledge of 
fossil with that of present forms and to re- 
construct the evolutionary picture in more 
precise terms. 
Genus Naso Lacepede 
Naso Lacepede, 1801. Hist. nat. poiss. Vol. 3, 
p. 105. (Type species by subsequent de- 
signation (Valenciennes, 1837, pi. 72, fig. 
1), Naso fronticornis Lacepede = Chaetodon 
unicornis Forskal.) 
Monoceros Bloch and Schneider, 1801. Syst. 
ichth. p. 180. [Preoccupied by Lacepede 
(ex Plumier), 1798. Hist. nat. poiss. Vol. 1, 
p. 357, in reference to a balistid.] 
Nason us Rafinesque. 1815. Anal, natur. p. 88. 
(Substitute name for Naso.) [Reference after 
Gill, 1885.] 
Priodon Quoy and Gaimard. Voyage autour 
du monde . . . Uranie . . . Zool. p. 377. 
(Type species, Priodon annulatus Quoy and 
Gaimard.) 
Naseus Cuvier. 1829- Regne animal. Ed. 2, 
vol. 2, p. 224. (Type species, Naso fronti- 
cornis Lacepede = Chaetodon unicornis For- 
skal.) 
Priodontichthys Bonaparte, 1833. Saggio. dis- 
trib. metod. anim. vert. p. 34. (Type spe- 
cies, Priodon annularis Cuvier and Valen- 
ciennes = Priodon annulatus Quoy and 
Gaimard.) [Reference after Gill, 1885.] 
Axinurus Cuvier and Valenciennes, 1835. Hist, 
nat. poiss. Vol. 10, p. 299- (Type species, 
Axinurus thynnoides Cuvier and Valen- 
ciennes.) 
Keris Cuvier and Valenciennes, 1835. Hist, 
nat. poiss. Vol. 10, p. 304. (Type species, 
Keris anginosus Cuvier and Valenciennes.) 
Callicanthus Swainson, 1839- Nat. hist. . . . 
fishes . . . Vol. 2, p. 256. (Type species, 
Aspisurus elegans Riippell = Acanthurus 
lituratus Bloch and Schneider.) 
