323 
Distribution and life history 
of two diminutive fflatfishes / 
Citharichthys gymnorhinus and C. cornutus 
(Pieuronectiformes: Paralichthyidae), 
in the western North Atlantic 
Abstract — Citharichthys cornutus and 
C. gymnorhinus, diminutive flatfishes 
inhabiting continental shelves in the 
western Atlantic Ocean, are infre- 
quently reported and poorly known. 
We identified 594 C. cornutus in 56 
different field collections (68-287 
m; most between 101-200 m) off the 
eastern United States, Bahamas, 
and eastern Caribbean Sea. Histor- 
ical records and recently captured 
specimens document the northern 
geographic range of adults on the 
shelf off New Jersey (40°N, 70°W). 
Citharichthys cornutus measured 
17.2- 81.3 mm standard length (SL); 
males (20.0-79.1 mm SL) and females 
(28.0-81.3 mm SL) attain similar 
sizes (sex could not be determined for 
fish <20 mm SL). Males reach nearly 
100% maturity at >60 mm SL. The 
smallest mature females are 41.5 mm 
SL, and by 55.1 mm SL virtually all 
are mature. Juveniles are found with 
adults on the outer shelf. Only 214 
C. gymnorhinus were located in 42 
different field collections (35-201 m, 
with 90% between 61 and 120 m) off 
the east coast of the United States, 
Bahamas, and eastern Caribbean Sea. 
Adults are found as far north as the 
shelf off Cape Hatteras, NC (35°N, 
75°W). This diminutive species (to 
52.4 mm SL) is among the smallest 
flatfishes but males (n = 131; 20.3—52.4 
mm SL) attain a slightly larger maxi- 
mum size than that of females (« = 58; 
26.2- 48.0 mm SL). Males begin to 
mature between 29 and 35 mm SL 
and reach 100% maturity by 35-40 
mm SL. Some females are mature at 
29 mm SL, and all females >35.1 mm 
SL are mature. Overlooked specimens 
in museum collections and literature 
enabled us to correct long-standing 
inaccuracies in northern distribu- 
tional limits that appear in contem- 
porary literature and electronic data 
bases for these species. Associated 
locality-data for these specimens 
allow for proper evaluation of distri- 
butional information for these species 
in relation to hypotheses regarding 
shifts in species ranges due to climate 
change effects. 
Manuscript submitted 27 May 2009. 
Manuscript accepted 26 April 2010. 
Fish. Bull. 108:323-345 (2010). 
The views and opinions expressed 
or implied in this article are those of the 
author (or authors) and do not necessarily 
reflect the position of the National Marine 
Fisheries Service, NOAA. 
Thomas A. Munroe (contact author ) 1 
Steve W. Ross 2 
Email address for contact author: munroet@si.edu 
1 National Systematics Laboratory/NMFS/NEFSC 
Smithsonian Institution 
Post Office Box 37012 
NHB, WC 57, MRC-153 
Washington, DC 20013-7012 
2 University of North Carolina at Wilmington 
Center for Marine Science 
5600 Marvin Moss Lane 
Wilmington, North Carolina 28409 
Citharichthys cornutus (Gunther, 
1880), the horned whiff, and C. gymno- 
rhinus Gutherz and Blackman, 1970, 
the anglefin whiff, are small-size, 
poorly known flatfishes inhabiting 
substrata located on the middle and 
outer continental shelves — primarily 
in subtropical and tropical waters of 
the western Atlantic Ocean (Gutherz, 
1967; Gutherz and Blackman, 1970; 
Topp and Hoff, 1972; Figueiredo and 
Menezes, 2000; 2003). Larvae of both 
species have been collected off Nova 
Scotia, Canada, but these were consid- 
ered strays from more southern locali- 
ties (Scott and Scott, 1988). These two 
species are morphologically similar 
and, although broadly sympatric in 
the western North Atlantic Ocean, 
are seldom taken together in the same 
collections. Their relatively small size 
(maximum to 55 mm standard length 
[SL] in C. gymnorhinus and 91 mm 
SL in C. cornutus), lack of commercial 
importance, infrequency of capture, 
and the probable low abundance of 
both species have resulted in their 
largely being ignored. 
Published, detailed life history in- 
formation for C. cornutus is sparse. 
Consequently, our knowledge of the 
biology, ecology, and geographic distri- 
bution of this species is limited to rel- 
atively few observations on maximum 
size (Parr, 1931; Longley and Hildeb- 
rand, 1941; Gutherz, 1967), size at 
maturity (Parr, 1931 [in part]; Long- 
ley and Hildebrand, 1941), reports of 
hermaphrodites (Gutherz, 1969), and 
general descriptions of geographic 
and bathymetric distributions (Parr, 
1931 [in part]; Longley and Hildeb- 
rand, 1941; Gutherz, 1967; Topp and 
Hoff, 1972). Citharichthys cornutus 
is found from temperate regions of 
the North Atlantic Ocean off New 
Jersey (Goode, 1880; reported as Ci- 
tharichthys unicornis, now considered 
a junior synonym of C. cornutus, see 
Norman, 1934; Fowler, 1952; Steves 
et al., 1999) and Hudson Submarine 
Canyon (Fahay, 2007) to subtropical 
waters off southern Brazil (Gunther, 
1880) and Uruguay (Figueiredo and 
Menezes, 2000; 2003). From the lim- 
ited data, it appears that C. cornu- 
tus reaches sizes to about 89 mm SL 
(Gutherz, 1967), and although this 
species is known from depths rang- 
ing from 20 to 408 m (Gutherz, 1967; 
Topp and Hoff, 1972), it has been cap- 
tured most frequently between 130 
and 370 m (Gutherz, 1967). 
Most published sources commonly 
cited for distributional information 
on C. cornutus are inaccurate. Data 
in Gutherz (1967) are the basis for 
the geographic range most frequently 
