Central Pacific Eels of the Genus Uropterygius, 
with Descriptions of Two New Species 1 
William A. Gosline 2 
In the Central Pacific, at least, Uropterygius 
is, after the related Gymnothorax , the largest 
and most difficult genus of eels. Inadequate 
knowledge precludes any final revision at the 
present time either of the genus as a whole or 
of the species in the region under considera- 
tion. The individuals are, for the most part, 
among the smallest and most inconspicuous 
of morays, and some species doubtless remain 
undescribed. Nomenclatorially, the final allo- 
cation of the older names to the various forms 
must await examination of the types or of 
topotypical material. Where the specimens 
available do not aid in the solution of nom- 
en clatorial problems, I have followed Schultz 
(1953: 140-159); to do otherwise would only 
be substituting one dubious name for another. 3 
The basic classification of the genus was 
laid down by Schultz (1943: 23-33; 1953: 
140-159). The present paper could not have 
been written without this groundwork. It is, 
indeed, something of an addendum to Schultz’s 
treatments of the genus, and full descriptions 
and synonymies have been omitted here. Its 
purpose is to clarify further the distinctions 
and relationships between Central Pacific spe- 
cies of Uropterygius , and to describe two 
new ones. 
1 Contribution No. 105, Hawaii Marine Laboratory, 
in cooperation with the Department of Zoology and 
Entomology. Manuscript received July 2, 1957. 
2 Department of Zoology and Entomology, Uni- 
versity of Hawaii, Honolulu. 
3 1 believe that the same nomenclatorial policy could 
advantageously be followed for other Central Pacific 
fishes. That the scientific names applied to most of the 
fishes from this area can only be provisional may as 
well be admitted. It is merely a question of what pro- 
visional set of names to accept. The nomenclature of 
Schultz et at. should be altered, of course, as the various 
groups become revised on a world-wide basis. How- 
ever, the adoption of such a policy should not be con- 
strued as a deterrent to further work on the zoological 
entities represented within the Central Pacific, or to the 
adoption of the nomenclatorial changes necessitated 
by such work. 
The genus, as here recognized, has the 
limits drawn for it by Schultz (1953: 99), i.e., 
Scuticaria is considered a synonym but An- 
ar chias is excluded as a separate valid genus. 
Within the area under consideration Uroptery- 
gius may be sufficiently defined as containing 
those muraenid eels with no lateral-line pore 
near the posterior nostril, with sharp teeth in 
the jaws, and with the fins restricted to the tail 
region. (An alizarin-stained specimen of U. 
knighti shows that in this species, at least, the 
rayed portions of the dorsal and anal fins com- 
mence about one head length ahead of the tip 
of the tail.) The investigated members of the 
genus, except U. xanthopterus , seem to be dif- 
ferentiated from other muraenids in having a 
single open lateral-line pore above and before 
the gill opening. Other morays examined 
(Muraena pardalis , Echidna poly zona, E. nebu- 
losa , various species of Gymnothorax , Rabula 
fuscomaculata , Anar chias allardicei, A. cantonen- 
sis, and A. leucurus) have two pores, one in 
front of the other, in this area (as does 
Uropterygius xanthopterus) . The one exception 
is Echidna zebra , which does not have any pore. 
The type of Uropterygius is U. concolor 
Riippell from the Red Sea. 
KEY TO THE CENTRAL PACIFIC SPECIES 
of Uropterygius 
1. Anus in front of or approximately under 
the middle of the length 3 
Anus at least two-thirds of the way back 
along the length. Species reaching at 
least 3 feet in length 2 
2. Posterior nostril over front border of or- 
bit; color plain brown U. sealei 
Posterior nostril over eye; color light 
with prominent round or oval dark 
blotches U. tigrinus 
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