Systematics

Monotypic. General decrease in size from east to west, especially in wing length (Prater et al. 1977, Cramp and Simmons 1983; but see Measurements, below). Genetic markers identified using random amplified polymorphic DNA (RAPD) revealed phylogeographic structure among samples from breeding populations at Churchill, Manitoba; Mackenzie, Northwest Territories; and Prudhoe Bay, AK, with most individuals (26 of 28) grouped with the breeding population from which they were taken (Haig et al. 1997).

Closely related to Common Ringed Plover, the 2 species classified as a superspecies by Mayr and Short (1970). Considered conspecific with Common Ringed Plover by some authorities (see review by Bock [1959]) and hypothesized as derived from single widespread stock of Common Ringed Plover (see Miller 1996). Although overlap in breeding range occurs on e. Baffin I., report of mixed pairs there (Smith 1969) not verified and no association of the 2 species noted by Wynne-Edwards (1952) or Sutton and Parmelee (1955). Displaying individuals of both species have been seen on St. Lawrence I., AK, where Common Ringed Plovers a casual breeder (Dunn 1993). Comparison of calls given during aerial display show similar pattern between Semipalmated and Common Ringed plovers (homologous features easily identified) but significant differences support recognition as separate species (Miller 1996; see Sounds: Vocalizations, vocal array). Phylogenetic study of genus Charadrius based on comparison of mitochondrial DNA (preliminary data from 600 base pair sequence of cytochrome b gene) reveals 8% sequence divergence between Semipalmated and Common Ringed plovers and suggests that the ringed plover complex is a monophyletic group, which also includes Killdeer, Piping and Wilson’s plovers, and, presumably (not yet sampled), Long-billed (C. placidus) and Little Ringed plovers (M. Peck pers. comm.).