A revision of the Madagascan cichlid genus Ptychochromis has led to the description of five new species and the erection of a new genus for a previously described fish.
Melanie Stiassny and John Sparks of the Department of Vertebrate Zoology at the American Museum of Natural History undertook an extensive study on the Ptychochromis genus to analyse the phylogeny of the group and assess whether those species currently included had the characteristics required to make them members of the group.
Three previously described species, P. oligacanthus, P. grandidieri and P. inornatus, were redescribed with updated diagnoses, and five new species were named: Ptychochromis makira (previously known as P. sp. "Makira"); Ptychochromis loisellei (previously known as P. sp. "Nord Est"); Ptychochromis curvidens (previously known as P. sp. "Montagne d'Ambre"); Ptychochromis insolitus (previously known as P. sp. "Mangarahara"); and Ptychochromis onilahy.
One of the species, P. onilahy, is believed to be extinct, while another, P insolitus, is extinct in the wild. A number of specialist cichlid breeders are conserving this species in aquaria.
The species formally known as Ptychochromoides katria, has been placed in a new genus under the name Katria katria. The genus is diagnosed by its unique colour pattern, slender caudal peduncle, higher number of vertebrae than relatives and the absence of paired anterior gas bladder chambers that approach the neurocranium.
The phylogeny produced was based upon a combination of morphological features and nucleotide characters from a combination of mitochondrial and nuclear genes. It places Ptychochromis and Katria in an unnamed clade which is diagnosed by a unique combination of characters of the sensory system, pharynx, palate and supraneural structures.
For more information on the new species see the paper: Stiassny MLJ and JS Sparks (2006) - Phylogeny and taxonomic revision of the endemic Malagasy genus Ptychochromis (Teleostei: Cichlidae) with the description of five new species and a diagnosis for Katria, new genus. American Museum Novitates, Number 3535 (2006) - 1-55.