Danio

Sanger, Thomas J. & McCUNE, Amy R., 2002, Comparative osteology of the Danio (Cyprinidae: Ostariophysi) axial skeleton with comments on Danio relationships based on molecules and morphology, Zoological Journal of the Linnean Society 135 (4), pp. 529-546 : 544

IMPLICATIONS FOR DANIO TAXONOMY AND

RELATIONSHIPS

The taxonomy of Danio is problematic and in need of revision (see Fang, 1997; Kullander, 2001). Ten genera and subgenera, including Brachydanio Weber & de Beaufort (1916) , have been synonomized with Danio ( Barman, 1991; Eschmeyer, 1998; Fang, 2000b). Only one morphological synapomorphy, the ‘danionin’ notch in the dentary, has been previously suggested for Danio ( Howes, 1979; Fang, 2000b; Kullander, 2001; but see Roberts, 1986). In the case of Brachydanio (sensu Talwar & Jhingran, 1991), no diagnostic characters have been described ( Barman, 1991; Fang, 2000b), although the name continues to be used occasionally in the nonsystematic literature. As discussed above, and in other studies done concurrently ( Kullander, 2001; Parichy & Johnson, 2001), there is ample support for the slender-bodied and deep-bodied clades. However, data are conflicting regarding the monophyly of Danio . Based on rather limited taxonomic samples (8–11 species), all molecular studies ( Meyer et al., 1995; Parichy & Johnson, 2001) and our morphological study support the monophyly Danio . In contrast, in a recently completed morphological analysis of 13 Danio species plus eight closely related genera ( Kullander, 2001) Danio was not monophyletic in the most-parsimonious tree. In the latter, several non- Danio genera (taxa not included in either our study or the molecular studies discussed above) were nested within Danio , some most closely related to the slender subclade and others allied with the deepbodied species. Support for the relationship between these additional genera and the slender-bodied clade was based on a single character, while support for two other genera with the deep-bodied clade is stronger. Given the strong support in all studies for the deep- and slender-bodied clades, it may be appropriate to assign distinct generic names to these two subclades. Whether this is appropriate can only be determined by a far more comprehensive study of both additional taxa and additional characters.