Phylogenetic Relationships of the Fundulus nottii Species Group (Fundulidae, Cyprinodontiformes) as Inferred from the Cytochrome b Gene

Abstract

The Fundulus nottii species group, commonly known as starhead topminnows, comprises five species of fishes distributed in the Atlantic and Gulf Coastal Plains and in the Mississippi Valley north to Lake Michigan. Allozyme (Cashner et al., 1992) and morphological (Wiley, 1977, 1986; Wiley and Hall, 1975) data support a monophyletic F nottii species group and its placement in the subgenus Zygonectes. However, these phylogenetic hypotheses conflict in their proposed relationships among F. nottii, F escambiae, and E lineolatus. Morphological data support a sister-group relationship between E nottii and F escambiae, corroborating a large-scale vicariant event around the Mobile Bay basin that has been observed in other freshwater groups (Wiley and Mayden, 1985). Allozyme data (Cashner et al., 1992) support E nottii and E lineolatus as sister taxa. The relationship of the F nottii species group to other species within Zygonectes is also controversial. Fundulus sciadicus, a group composed of F chrysotus, F cingulatus, and F luciae and the F notatus species group have all been hypothesized to be sister to the F nottii species group (Griffith, 1972; Wiley, 1986; Cashner et al., 1992). The purpose of this study was to assess phylogenetic relationships within the E nottii species group and the relationships of this species group to other members of Zygonectes. We used the first 357 nucleotides from the 5' end of the