New Records, Distribution and Diagnostic 
Characters of Virginia Ictalurid Catfishes 
With An Adnexed Adipose Fin 
Noel M. Burkhead and Robert E. Jenkins 
Department of Biology, 
Roanoke College, Salem, Virginia 24153 
AND 
Eugene G. Maurakis 
Environmental Affairs Department, 
Potomac Electrical Power Company, 
1900 Pennsylvania Avenue NW, Washington, DC 20068 
ABSTRACT.— KQCQWi introductions of Ictalurus melas and Pylodictis 
olivaris and the discovery (possible introduction) of /. brunneus has 
raised the number of ictalurids with an adnexed adipose fin to eight 
species in the Roanoke River drainage. Introduction of /. furcatus to 
other drainages raised the Virginia total to nine. Although most of these 
species are widely distributed in North America, none is native in all 
Virginia drainages. Most species have been variously introduced, and /. 
brunneus and I. platycephalus exhibit an atypical distributional in- 
terrelationship. Key characters for separating these two flathead 
bullheads from typical bullheads (/. melas, 1. natalis, 1. nebulosus) are 
described, and some diagnostic characters different from those generally 
used are emphasized for distinguishing I. brunneus from /. platycephalus, 
and I. melas from /. nebulosus. These and characters of other ictalurids 
with an adnexed adipose fin are discussed; a key is provided for the 
species of Virginia drainages. 
INTRODUCTION 
Exceptional or significant new records, occasional recent misiden- 
tifications, vexatious old records, and an atypical distributional in- 
terrelationship between two Virginia ictalurids led to this report. 
Although most species have been long known, the ictalurids with an ad- 
nexed (free) adipose fin still present at least local problems in identifica- 
tion, and consequently may subvert zoogeographic studies in North 
America. Problems have extended elsewhere. For example, Banarescu 
(1968) found that the bullhead widely introduced in Europe was actually 
Ictalurus melas (Rafinesque) instead of I. nebulosus (Lesueur). Important 
external characters are few, and most are variable and widely shared 
among similar appearing, often sympatric species; no consistently present 
external character state of juvenile and adult Ictalurus appears unique to 
a single species. 
The Roanoke River drainage is now known to harbor eight species 
of ictalurids with an adnexed adipose fin, a larger complement than oc- 
curs in the Mississippi River basin. A total of nine species is now known 
from Virginia: /. brunneus (Jordan), snail bullhead; I. catus (Linneaus), 
white catfish; I. furcatus (Lesueur), blue catfish; /. melas, black bullhead; 
75 
Brimleyana No. 4: 75-93. December 1980. 
