Systematics of the Menidia beryllina Complex (Pisces: Atherinidae) from the Gulf of Mexico and Its Tributaries

Abstract

The M. beryllina complex from the Gulf of Mexico and Gulf slope drainages includes those forms referred to M. audens Hay, M. beryllina (Cope), M. b. atrimentis, M. b. peninsulae, M. peninsulae and M. p. atrimentis. The relationship between the Mississippi Valley [USA] form (M. audens) and the coastal form (M. beryllina) is clinal for several purportedly diagnostic characters and within populations, character variation is often large and differences between size classes are noted. Variation of the M. beryllina phenotype is also found in other rivers. The relationship between M. beryllina and M. peninsulae is obscured by historical treatment. M. peninsulae, from Florida [USA] to Tamiahua, Mexico, is distinguished by several morphometric and vertebral characteristics. M. audens, M. b. atrimentis and M. p. atrimentis are synonyms of M. beryllina and that M. peninsulae is a distinct species; a redescription of M. peninsulae is included.