A New Atherinid Fish — Gosline 
49 
Iso hawatiensh belongs to the small and 
aberrant atherine subfamily Notocheirinae 
(Schultz, 1950: 150). Schultz (1948: 5) divides 
this subfamily into three genera. Of these 
Notocheirus^ based on two specimens from 
Chile, is certainly distinct. However, Schultz's 
other two genera~Iro and Tropidostethops — 
are so closely related that I can find no 
morphological or philosophical grounds for 
separating them. The only distinguishing 
character Schultz (1948) gives is the con- 
figuration of the silvery lateral band quoted 
in section 1 of the key given below. This 
difference hardly seems of generic value; if 
other more significant differences exist, they 
are not stated in the literature. Furthermore, 
Jordan and Hubbs, in an earlier revision of 
the Atherinidae (1919: 47), have compared 
the genotypes of Iso and Tropidostethops and 
consider them to be congeneric. This is par- 
ticularly significant as Jordan and Hubbs 
split the atherine genera rather finely (they 
divide 149 species and subspecies between 
38 genera, giving an average of 3.9 species 
and subspecies per genus). Smith (1949: 324), 
writing subsequently to Schultz, also fails 
(by inference) to recognize these two genera. 
If both genera are recognized, Iso becomes 
monotypic, and Tropidostethops would con- 
tain four known species. Even the geographic 
distribution of such genera would not be 
significant. Iso would be limited to Japan, 
whereas Tropidostethops would have repre- 
sentatives in southern Africa, India, Aus- 
tralia, and now Hawaii. 
Finally' Schultz's fine discrimination be- 
tween these two atherinid genera is not con- 
sistent with his own broad interpretation of 
genera in certain other groups, e.g., in eels 
(Schultz and Woods, 1949). 
For the above reasons I consider Tropido- 
stethops, to which Iso hawaiiensis would be as- 
signed if Tropidostethops were considered 
valid, a synonym of Iso. 
In view of the addition of Iso hawaiiensis 
and of the redescription of Iso natalensis by 
Smith (1935: 178, pL 19, fig. c), Herre's 
(1944: 47) key to the species of this genus 
stands in need of revision. It may be re- 
written as follows: 
1. ” Silvery lateral band continuous and 
not interrupted. (Japan) . 
....................... .Iso flos-maris 
"Silvery lateral band fading and inter- 
rupted or narrowly constricted on 
caudal peduncle, then continuing 
and expanding, ending in a promi- 
nent silvery area”^ ................. 2 
2. Maxillary with external teeth. Scales in 
a longitudinal series 40-44. (India) 
...................... .Iso flos-indicus 
Maxillary without external teeth ....... 3 
3. Scales in a longitudinal series about 38; 
teeth apparently absent. (Hawaii) . . 
...................... Iso hawaiiensis 
Scales in a longitudinal series more 
than 45 ; teeth present 4 
4. Depth 3. 5-4.0 in standard length; 
scales in a longitudinal series about 
49. (Australia) ......... .Iso rhothophilus 
Depth 3. 2-3. 4 in standard length; 
scales in a longitudinal series about 
74. (South Africa) ....... .Iso natalensis 
With the addition of Notocheirus huhbsi to 
the above species, the distribution of the 
Notocheirinae— South Africa, India, Aus- 
tralia, Hawaii, and Chile— becomes unique, 
so far as I am aware, among fish groups. 
REFERENCES 
Herre, a. W. 1944. Notes on fishes in the 
zoological museum of Stanford University, 
XVII. New fishes from Johore and India. 
Biol. Soc. Wash., Proc. 57: 45-52. 
Jordan, D. S., and C. L. Hubbs. 1919. A 
monographic review of the family of Atherini- 
dae or silversides. Stanford Univ., Pubs., 
Univ. Ser., Biol. Sci. 87 pp., 12 pis. 
Schultz, L. P. 1948. A revision of six sub- 
families of atherine fishes, with descrip- 
tions of new genera and species. U. S. 
■^Quoted from Schultz (1948: 6). 
