A new species of livebearing tropical fish has been described from the Rio Uruguai drainage in the Republic of Uruguay.
Cnesterodon holopteros is a member of the Poeciliinae and has just been named in a paper in Zootaxa by Paulo Lucinda, Thomas Litz and Roberto Recuero.
Females of Cnesterodon holopteros have eight or nine vertical bars which run along the flanks and extend from the back almost to the belly. Some females have just seven bars, but in all specimens they typically measure about one to three scales in width.
The gonopodium of male Cnesterodon holopteros is gently arched and narrows towards the tip where there is a bony "style" and a distal filament.
The pelvic-fin rays are unbranched and the species has four branchiostegal rays.
The Cnesterodon genus contains another seven species, including: Cnesterodon brevirostratus; Cnesterodon carnegiei; Cnesterodon decemmaculatus; Cnesterodon hypselurus; Cnesterodon omorgmatos; Cnesterodon raddai and Cnesterodon septentrionalis.
The Cnesterodon genus is a member of the poeciliid subfamily Poeciliinae, which contains around 27 different genera.
For more information see the paper: Lucinda PHF, Litz T and R Recuero (2006) - Cnesterodon holopteros (Cyprinodontiformes: Poeciliidae: Poeciliinae), a new species from the Republic of Uruguay. Zootaxa 1350: 21-31 (2006).