A new species of killifish from the genus Simpsonichthys has been described.
South American killifish authority Wilson Costa of the Department of Zoology at the Federal University of Rio de Janeiro in Brazil named the new fish Simpsonichthys nielseni in a paper in the systematics journal Zootaxa.
The new species is an annual killifish and was found in the middle Sao Francisco River basin in Brazil.
S. nielseni is a member of the Simpsonichthys notatus group, which includes a number of fishes, including radiosus, trilineatus, rufus, similis, notatus and stellatus, all of which have a characteristic pattern of scales.
The new fish is differentiated from others in the notatus-group by the colour of the tail fin of males, which have six or seven light blue stripes.
It shares a colour characteristic with the related S. stellatus by having elongated light spots with black zones on the dorsal base of males.
For more details see the paper: Costa, WJEM (2005) - Simpsonichthys nielseni sp. n. (Teleostei: Cyprinodontiformes: Rivulidae): a new annual killifish from the Sao Francisco River basin, Brazil. Zootaxa 1039: 57-64.