Comments: A number of subspecies have been described, but only two (heteroclitus and macrolepidotus) have been recognized in most recent studies. The genus Fundulus was removed from Atheriniformes:Cyprinodontidae and placed in Cyprinodontiformes:Fundulidae by Parenti (1981); pending confirmation based on other character suites, this change was not accepted in the 1991 AFS checklist (Robins et al. 1991). Studies of mitochondrial DNA of subspecies heteroclitus and macrolepidotus of the U.S. Atlantic coast indicate that these two taxa exhibit secondary intergradation in northern New Jersey, Long Island, and in Chesapeake and Delaware bays (Gonzalez-Villasenor and Powers 1990), Able and Felley 1986). See Brown and Chapman (1991) and Powers (1989) for additional genetic studies of these populations. See Wiley (1986) for a study of the evolutionary relationships of Fundulus topminnows based on morphological characters. See Cashner et al. (1992) for an allozyme-based phylogenetic analysis of the genus Fundulus.