nder each were located; one had two nests of E. 
quamiceps (approximately 200 mm apart); the 
ther had one nest of E. squamiceps and one of E. 
ennicotti. In both instances of double occupancy 
f a nest stone, the two nests were completely sep- 
rated from one another by substrate material when 
1e rock was in place in the stream. Similar sharing 
f one nest stone was described by Lake ( 1936:823 ) 
r E. flabellare. 
The spawning behavior of E. squamiceps is similar 
) that of E. flabellare, described by Lake (1936) 
ad Winn (1958a and 1958b). Differences in’ the 
yawning behavior of E. flabellare from that of E. 
juamiceps are the head-to-tail egg-laying position, 
ie fact that females may remain inverted for as 
ng as 2 hours, the habit of the female of usually 
ying only one egg at a time, and the intolerance 
y the male of the presence of a right-side-up female 
ider the nest stone. 
exual Dimorphism 
Winn (1958b:172) listed among the sexually 
morphic characters of E. flabellare the larger anal, 
cctoral, and pelvic fins of the male. In addition 
behavioral (territorial) and morphological (colora- 
yn and size) differences between the sexes of E. 
uamiceps, the anal, soft-dorsal, pelvic (P<0.01), 
id pectoral fins (P<0.10) were significantly longer 
males. The depth of the caudal peduncle was also 
eater in males (P<0.01). 
DEVELOPMENT AND GROWTH 
Eggs incubated in aquaria at temperatures vary- 
g from 18° to 22°C (64°-72°F) hatched in 270-275 
urs (11.3-11.5 days), and eggs incubated at 22°- 
°C .(72°-79°F) hatched in 125-130 hours (5.2-5.4 
ys). 
Three nests of E. squamiceps eggs were found to 
hatching in Big Creek on 3 May 1971, including 
e nest first discovered and marked on 17 April. 
is nest had been observed periodically between 
-April and 3 May, during which time water tem- 
ratures varied from 14° to 18°C (57°-64°F). No 
gs were added during this time; thus, a minimum 
16 days of incubation is required at this tempera- 
e range. Lake (1936:826) found eggs of .E. flabel- 
e to have much longer incubation periods: 14-16 
ys at an average temperature of 74°F, 21 days at 
*=71°F, and 30-35 days at 63°-68°F. 
E. squamiceps hatchlings (Fig. 8) were 6.5 mm in 
Fig. 8—Etheostoma squamiceps hatchling. 
11 
total length and mostly translucent, but they had 
red blood, black melanophores over most of the 
body, and metallic gold eyes. Melanophores were 
especially prominent on top of the head and on 
the lower one-third of the yolk sac. Pectoral fins 
and the lower jaw were well developed, as they 
are in E. flabellare hatchlings (Lake 1936:826-827 ), 
making these two species more precocious at hatching 
than are Etheostoma gracile (Braasch & Smith 1967:9 ) 
and Percina sciera (Page & Smith 1970:9). 
In aquaria, fry left the nest stone soon after 
hatching and sought refuge among the gravel sub- 
strate. Propulsion was accomplished by rapid move- 
ments of the caudal fin. 
The smallest specimens examined from the study 
areas were two 12-mm females collected 20 July 
1971 in Big Creek. Several specimens from 13 to 
20 mm were collected in a number of habitats in 
both study areas between 23 June and 25 August of 
1971 and 1972. 
At 12 mm juveniles had essentially the morphology 
of adults but were without scales on the nape, breast, 
and belly, and were without a lateral-line canal. In 
75 
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MONTHS OF AGE 
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MONTHS OF AGE 
Fig. 9—Size distribution by age of Htheostoma squami- 
ceps collected in A, Big Creek, and B, Ferguson Creek. 
Black circles represent sample means for males; white 
circles represent sample means for females. From Big Creek 
601 specimens were collected, and from Ferguson Creek 430. 
