Academic journal article The American Midland Naturalist

Evidence Supporting Two New Forms and One Previously Described Race within the Cottus Carolinae Species-Complex from the Ozark Highlands

Academic journal article The American Midland Naturalist

Evidence Supporting Two New Forms and One Previously Described Race within the Cottus Carolinae Species-Complex from the Ozark Highlands

Article excerpt

I present preliminary data describing two new forms within the Cottus carolinae species-complex from the Ozark Highlands, the eyelash sculpin and the fringe-head sculpin. The eyelash and fringe-head sculpins can be diagnosed from all other species of Cottus by cirri (thin fleshy appendages), a character heretofore unknown in the genus. The eyelash sculpin can be further diagnosed by a few cirri above the eye and the fringe-head sculpin by a large number of cirri on the head and elsewhere. In addition, I provide data on pectoral fin ray number in the C. carolinae species-complex that validates the recognition of the Black River race in the Ozark Highlands (18-19 in Black River race, 13-17 in all other C. carolinae). The distribution of Ozark Highland members of the C. carolinae species-complex and a new size record are also discussed.

INTRODUCTION

The genus Cottus contains approximately 42 recognized species (Eschmeyer, 1998; Kinziger et al., 2000; Markle and Hill, 2000). However, the true diversity of the genus is uncertain because many taxa represent species-complexes (e.g., C. gobio: Kontula and Vainola, 2001; and C. hypselurus: Robins, 1954; Gasper et al., 2000). One of the taxonomically most confusing species in the genus is C. carolinae, the banded sculpin. Cottus carolinae is distributed in the midwestern and eastern United States and has been recognized as a species-complex for nearly 50 y. (Fig. 1, inset; Robins, 1954). Currently, mersitic and morphological data suggest at least 11 taxa are members of this complex including five races, three subspecies and three undescribed forms (Table 1) and it is possible that other taxa such as the broadband sculpins may be members (Jenkins and Burkhead, 1994). I present taxonomic information on three taxa within the C. carolinae species-complex that are endemic to the Ozark Highlands. Two of the taxa discussed are newly diagnosed based on the presence, abundance and distribution of cirri, a character heretofore unknown in the genus. The third taxon, the Black River race, is a form previously described within C carolinae based on a unique pectoral fin ray count (18-19 in Black River race, 15-17 in all other C. carolinae), but in need of validation because original data substantiating this taxon was based on a small number of specimens (n = 20) from three collections (Robins, 1954).

METHODS

A total of 81 collections of Cottus carolinae were examined including 62 from the Ozark Highlands (Fig. 1) and 19 from other portions of this species' range (see materials examined). All specimens from the Ozark Highlands were examined for the presence, abundance and position of cirri (thin fleshy appendages) and number of pectoral fin rays (left and right sides). Data were not recorded for both characters from every specimen because in some individuals pectoral fin rays were missing. The 19 collections from the other portions of C. carolinae range were examined for cirri attributes only.

RESULTS AND DISCUSSION

Cirri-Cirri were present on 110 of 114 individuals (21 collections) of Cottus carolinae from several Ozark Highlands streams including a small direct Missouri River tributary and the Osage, Gasconade and Meramec river drainages. Conversely, no cirri were recorded from specimens of C. carolinae examined from other areas in the Ozark Highlands (260 individuals from 41 collections) or other localities throughout this species range (112 individuals from 19 collections). Moreover, cirri have never been reported in any taxonomic treatments of Cottus species nor are they evident in any drawings or photographs in these accounts (e.g., Robins, 1954; Robins and Miller, 1957; Watanabe, 1960; Berg, 1965; Williams and Robins, 1970; Page and Burr, 1991; Etnier and Starnes, 1993; Jenkins and Burkhead, 1994). Thus, the Ozark Highland populations possessing cirri represent the first documented occurrence of cirri in the genus Cottus.

Cirri appear as fleshy appendages concentrated above the eyes or on the head and elsewhere (Fig. …

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