Bedotia Regan, 1903

John S. Sparks & Leila M. R. Rush, 2005, A new rainbowfish (Teleostei: Melanotaenioidei: Bedotiidae) from the southeastern highlands of Madagascar, with comments on the biogeography of Bedotia., Zootaxa 1051, pp. 39-54 : 39-41

[[ Genus Bedotia Regan ]]

Introduction

The melanotaenioid family Bedotiidae is endemic to Madagascar and comprises two genera, Bedotia and Rheocles . As their common name, Malagasy rainbows or rainbowfishes, implies, bedotiids generally are colorful fishes. Bedotiids are elongate, laterally compressed, and rarely exceed 100.0 mm SL. Most bedotiids exhibit varying degrees of sexual dimorphism, which is quite pronounced in some species. Bedotiids occur exclusively in freshwater environments and are distributed in small to medium-sized forested rivers and streams, occasionally in swamps and marshes, spanning nearly the entire eastern versant of Madagascar. All species of Bedotia and Rheocles are restricted to eastern drainages, less R. derhami , which is endemic to a tributary of the westward draining Sofia River located in the northeast of the island.

In a species-level phylogenetic hypothesis for Bedotiidae based on an analysis of nucleotide characters from a combination of mitochondrial and nuclear genes, Sparks and Smith (2004a) demonstrated that Bedotiidae and Bedotia are monophyletic, but that Rheocles is paraphyletic (Fig. 1). A comprehensive phylogenetic analysis of Bedotia has yet to be undertaken via the use of anatomical features; nevertheless, monophyly of the genus has been hypothesized in a number of recent comparative morphological studies (Stiassny 1990; Dyer & Chernoff 1996; Aarn & Ivantsoff 1997). Morphologically, Bedotia is characterized by the presence of a deep notch, the "Bedotia notch", on the dentigerous margin of the premaxilla (Stiassny 1990: fig. 16a).

Bedotia Regan 1903 comprises six nominal species ( B. madagascariensis Regan 1903 , B. geayi Pellegrin 1907 , B. longianalis Pellegrin 1914 , B. tricolor Pellegrin 1932 , B. marojejy Stiassny & Harrison 2000 , and B. masoala Sparks 2001 ). Apart from coloration, pigmentation pattern, and minor variations in body shape, Bedotia is a morphologically conservative group of fishes. Until recently, the genus was poorly represented in museum collections, which has precluded detailed phylogenetic studies of their intrarelationships. Fortunately, much additional material has been collected from throughout eastern Madagascar over the past 15 years (Loiselle & Stiassny 2003; Sparks & Stiassny 2003). An examination of these collections, which comprise several newly discovered populations from remote regions of the island, reveals several presumably new species that are distinguishable in terms of pigmentation pattern, coloration, and body shape (Sparks & Stiassny 2003).

Sparks and Smith (2004a) included all nominal species of Bedotia in their molecular phylogenetic study of rainbowfishes, as well as representatives from these recently discovered populations (Fig. 1). Within this phylogenetic framework for Bedotia , and based on morphological comparisons to all nominal and undescribed species of the genus, including the type series for all species, a new species of Bedotia from the southeastern highlands of Madagascar is described. A brief discussion on the biogeography of Bedotia is also presented.