THE LIFE HISTORY OF THE DUSKY DARTER, PERCINA SCIERA, 
IN THE EMBARRAS RIVER, ILLINOIS 
THERE ARE OVER 100 DESCRIBED SPECIES 
of darters, which represent marked degrees of adapta- 
tion and show considerable variation in ecological and 
reproductive characteristics. A few species have been 
studied in detail, and certain aspects of the life histories 
of several have been investigated (see Literature Cited 
sections in Winn 1958a and Braasch & Smith 1967), 
but for most of them ecological information is limited 
chiefly to observations on their habitats in different 
parts of their ranges. Among the latter are the species 
in the subgenus Hadropterus of Percina, for which 
habitat requirements have been recently described 
(Suttkus & Ramsey 1967) but for which reproductive 
habits, growth, diet, and demographic parameters re- 
main virtually unknown. 
The subgenus Hadropterus included only nigro- 
fasciatus Agassiz, 1854, and scierus Swain, 1883, until 
the recent descriptions of lenticula Richards & Knapp, 
1964, and aurolineata Suttkus & Ramsey, 1967. Three 
of the species are restricted to the Gulf and Atlantic 
coast drainages; the fourth (sciera) is more widely dis- 
tributed and is the subject of the present study. 
The dusky darter was described as Hadropterus 
scierus from Bean Blossom Creek, Monroe Co., Indiana 
(Swain 1884:252) and, except for brief assignments 
to the genera Serraria and Etheostoma, was so known 
until Bailey, Winn, & Smith (1954:140) reduced the 
number of darter genera to three and relegated Hadrop- 
terus to subgeneric rank. Currently, the species iS 
regarded as consisting of two subspecies, the northern 
dusky darter (Percina s. sciera) and the Guadalupe 
River dusky darter (P. s. apristis Hubbs, 1954), an 
endemic in the Guadalupe River system of Texas. 
Percina sciera (cover illustration) is a large darter, 
with the adults ranging from 2 to 4 and occasionally 5 
inches in total length. The adult is light olive-green 
dorsally, with a pattern of black or brown markings, and 
nearly white below. A dark band extending around the 
snout, through the eye, and across the opercle connects 
to a broken lateral band of 7-12 large, dusky, oblong 
blotches on each side. The latter alternate with 7-10 
This paper is published by authority of the State of Illinois, 
IRS Ch, 127, Par. 58.12, and is a contribution from the Section 
ot Faunistic Surveys and Insect Identification of the Natural 
History Survey. It was submitted in its original form by 
Lawrence M, Page in partial fulfillment of the requirements for 
the degree of Master of Science in the Graduate College of the 
University of Illinois. Mr. Page is a research assistant at the 
Illinois Natural History Survey; Dr. Smith is Head of the 
Section of Faunistic Surveys and Insect Identification at the 
Survey and Professor of Zoology at the University of Illinois. 
Lawrence M. Page and Philip W. Smith 
dark blotches, which cross the midline of the back. 
Three vertical dark blotches on the caudal fin base 
form a distinctive, partially fused bar. A dark teardrop 
is usually lacking. The fins are nearly transparent but 
have small pigment spots along the spines and rays, 
which give the appearance of faint bars. 
The male differs from the female in having a mid- 
ventral row of large and strongly toothed scales and a 
smaller and less rounded genital pore. 
The young of P. sciera are distinguishable from the 
young of the superficially similar P. maculata and other 
species of Percina in the Wabash drainage by the dis- 
tinctive fused blotches on the base of the caudal fin. 
The dusky darter occurs from the Elk River of 
West Virginia (Richards & Knapp 1964:700), Tennes- 
see River system of Kentucky and Tennessee, and the 
Black Warrior-Tombigbee system in Alabama south- 
ward to the Gulf Coast (Suttkus & Ramsey 1967:138) 
and westward through Mississippi and Louisiana to 
central Texas, southeastern Oklahoma, and southeastern 
Missouri (Trautman 1957:535). Its range extends 
northward to eastern Illinois, throughout most of Indi- 
ana with the northernmost record in the upper Tippe- 
canoe River (Gerking 1945:85), and into the Scioto 
River drainage of south-central Ohio (Trautman 1957: 
535). In Illinois the species is restricted to the Ohio- 
Wabash drainage, and it is common only in the 
Embarras River and Middle Fork of the Vermilion 
River and their tributaries (Fig. 1). 
We are indebted to Raymond T. Schaaf, Hartley F. 
Hutchins, Dorothy M. Smith, Norman D. Penny, and 
the late Robert L. Hass for aid with field work; to out 
associates Donald W. Webb, John D. Unzicker, Milton 
W. Sanderson, and Herbert H. Ross for helping with 
identifications of arthropod fragments in the darte! 
stomachs; to Marvin C. Meyer, University of Maine, 
for identifying a leech parasite; to Harmon F. Smith, 
Illinois State Water Survey, for providing data on 
water chemistry of the Embarras River. We are gratt- 
ful to Richard M. Sheets, Survey technical illustrator, 
for preparing the illustrations, except those of the darter 
which were done by Alice Ann Prickett, University of 
Illinois School of Life Sciences; to Wilmer D. Zeht, 
Survey photographer, for the photographs; to Ou! 
colleagues W. C. Childers and J. A. Tranquilli fol 
temporary use of one of their aquaria and R. W. Lari- 
more for lending us a 30-foot electric seine and 115~ 
generator. 
COVER ILLUSTRATION: Adult female Percina sciera sciera collected in October in the Middle Fork, Vermilion County. 
Illinois. From a watercolor by Mrs. Alice Ann Prickett. 
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