Virginia Ictalurid Catfishes 
87 
The cardiform teeth of /. platycephalus are small and fairly uniform in 
size. The premaxillary tooth patch and cardiform teeth size differences 
are not evident in small specimens. These characters were first recognized 
by Lundberg (1970). 
The greatest meristic differences between /. brunneus and I. 
platycephalus are in anal rays and a character index (Tables 2 and 3). Fre- 
quency ranges of all counts differed slightly from data of Yerger and 
Relyea (1968), indicating possible geographic variation. A slightly higher 
range of character index values exists in Roanoke drainage /. brunneus 
when compared to data of Yerger and Relyea (1968) from some more 
southerly drainages, and results in greater meristic overlap between the 
two species in the Roanoke. 
The difference in mouth position between the species conformed to 
Yerger and Relyea’s (1968) description; however, we do not advocate 
general use of the character, as the difference seems to be only an average 
one and is not as obvious as barbel pigmentation. 
Typical bullheads. — Three species of typical bullheads (or the natalis 
group of Lundberg 1975) inhabit Virginia waters: /. natalis, /. nebulosus 
and /. melas. These are best separated from the flathead bullhead group 
by the absence of a discrete dark blotch at the base of the dorsal fin (Fig. 
3E) and by small eye size (Fig. 2). 
Ictalurus natalis is easily distinguished from the others by its un- 
pigmented mental barbels. The dark blood pigments in vessels of these 
barbels should not be confused with the presence of melanophores. 
Preserved blood in mental barbels appears as a dark line. The remaining 
species, /. nebulosus and /. melas, have often been reported to be 
separable by the character of the serrae on the posterior edge of the pec- 
toral spine: moderate serrae in /. nebulosus, weak serrae in /. melas 
(Trautman 1957; Blair et al. 1957; Hubbs and Lagler 1958; Pflieger 1975; 
and others). The posterior pectoral spine serrae in /. melas are variable, 
being absent to moderately developed. Although most often weakly 
developed in adult /. melas, the pectoral serrae are unreliable for con- 
sistently distinguishing /. melas from /. nebulosus. Ictalurus melas is best 
distinguished from I. nebulosus by higher (rarely overlapping) gill raker 
counts (Table 1). The single I. melas possessing 15 gill rakers on the right 
arch had 17 on the left arch. 
Fin pigmentation differences have also been reported. Of these 
characters, only the depigmented “bar” at the caudal base of I. melas is 
consistently present, and then only in larger juveniles and adults. 
However, it is often evident only when directly compared to specimens of 
I. nebulosus. 
Forked-tail Ictalurus. — Of the three species in this group, I. catus is 
readily separated by a moderately forked tail (Fig. 3H) and low anal ray 
counts, usually 22-24, (22-25, x = 23.1). Variation exists in the anal ray 
count ranges reported for I. catus: 19-22 (Jordan and Evermann 1896); 
