Two new species of dwarf cichlid from the Apistogramma genus have been described, one of which is the smallest known to science.
The first of the new cichlid species, Apistogramma salpinction, comes from the relatively typical apisto habitat of still or lentic waters, but the other one Apistogramma angayuara, is rather more unusual.
Not only is Apistogramma angayuara the smallest Apistogramma species known (according to the scientists who described the species), with the largest male measuring just 24.7 mm and the largest female a mere 22.7 mm, it is also found in rapid flowing water and feeds predominantly upon rhizopods.
This trophic niche is so unusual that the species is believed to be the first cichlid discovered with a significant proportion of rhizopods in its stomach contents.
The new cichlids, have just been described by Sven Kullander of the Swedish Museum of Natural History and Effrem Ferreira of INPA in Manaus in the journal Neotropical Ichthyology.
The rheophilic Apistogramma angayuara was found among rapids near the cachoeira Vira Mundo on the Rio Trombetas system and is thought to be a member of the pertensis species group.
The fish has three prominent stripes made up by dark spots along the sides of the abdomen, a caudal spot and a low dorsal fin in adult males.
The other fish, Apistogramma salpinction, was found in a swamp believed to be connected to a stream known as Igarape Caxipacore about 40 miles from Cachoeira Porteira.
It's a showy fish, with some similarities with the Apistogramma cacatuoides group.
Kullander and Ferreira say that salpinction has caudal fin streamers, like those of cacatuoides in adult males, and prolonged anterior dorsal fin lappets.
A. salpinction also has a distinctive colour pattern that sets it apart from related apistos: "The colour pattern includes a lateral band and abdominal stripes that become darker and have much lighter interspaces on the caudal peduncle, and a caudal spot that is divided into elongated blotches continuing the lateral band and upper two abdominal stripes respectively."
For more details on the new species see the paper: Kullander, SO and Ferreira, E. (2005) - Two new species of Apistogramma Regan (Teleostei: Cichlidae) from the rio Trombetas, Par State, Brazil. Neotropical Ichthyology, 3(3):361-371, 2005.