The systematics of the sculpins (Cottus) of the Holston River systems

A study was conducted to identify and characterize the species of sculpins (Cottus) that occur in the Holston River drainage of the Tennessee River system. With the considerable intra and interpopulational variation seen within sculpin species wide ranging studies fail to recognize patterns of variation that might be revealed from a more intensive study of a single river drainage. Collections were made on regular intervals from throughout the Holston River system in order to define population boundaries and establish possible genetic exchange between species. A series of meristic, mensural, and qualitative characters were developed to reliably separate the species.

Four species were identified from the Holston River. drainage. These include Cottus carolinae (Gill), Cottus bairdi Girard, Cottus baileyi Robins, and the undescribed Holston broadband. In addition, there was evidence of limited gene exchange between Cottus bairdi and C. baileyi in the lower Laurel Creek area of the upper South Fork Holston River. There was no evidence that the Kanawha sculpin, an undescribed species from the New River system of Virginia, has a relict population inMossy Creek of the Lower Holston River. The meristic and mensural characters useful in separating the species were as follows: number of pectoral rays, number of lateral-line pores, length and width of caudal peduncle, body depth, body banding widths, second dorsal fin base length, and palatine tooth patch length. The qualitative characters useful in separating the species were as follows: condition of the lateral line, presence or absence of a palatine tooth patch, degree of chin mottling, condition of the three preopercular spines, first and second dorsal fin pattern, body pigmentation, degree of post-pectoral prickling, and time of breeding.

This study demonstrates that a regional analysis was useful for uncovering patterns unseen by wide-ranging studies encompassing several river drainages.