Nine new species of cichlid have been described during a review of the South American genus Cichla.
Scientists conducted an in-depth study of the Cichla genus and identified 15 species, nine of which are new to science.
Sven Kullander of the Swedish Museum of Natural History and Efrem Ferreira of Instituto Nacional de Pesquisas da Amazonia (INPA) published the revision in a special edition of the journal Ichthyological Exploration of Freshwaters.
The same authors recently published a study on Symphysodon, in which a new species was described as Symphysodon tarzoo.
The 109-page study recognises Cichla ocellaris, C. temensis, C. orinocensis, C. monoculus, C. nigromaculata and C. intermedia as valid and describes Cichla mirianae, C. melaniae, C. piquiti, C. thyrorus, C. jariina, C. pinima, C. vazzoleri, C. kelberi and C. pleiozona for the first time.
The species are distinguished by differences in their juvenile and adult colouration and their meristics, particularly scale and fin counts.
VariationCichla, which are known as Peacock bass or Tucanare, are a major food and game fish in South America.
The genus is widely distributed in the Amazon, Tocatins and Orinoco river basins, as well as some of the smaller Atlantic drainage rivers. Many Cichla species have also been transplanted into other waters for fishing and food.
However, despite their importance, their taxonomy has been confused and traditionally just a few species with apparently variable markings have been identified.
This study separates the fish into a number of distinct groups. Six species - Cichla ocellaris, C. orinocensis, C. monoculus, C. nigromaculata and two new fish, C. kelberi and C. pleiozona - have a juvenile colour phase consisting of three dark blotches on the side and a dark band connecting the posterior blotch to the dark blotch at the base of the caudal fin.
The remaining nine species have three dark blotches on the flanks, as well as a dark horizontal band running from the head to the dark blotch at the base of the caudal peduncle. This group includes: C. temensis, C. intermedia and seven new species: C. mirianae; C. melaniae; C. thyrorus; C. jariina; C. pinima; C. vazzoleri and C. piquiti.
Cichla have lateral line scale counts ranging from 67 to 128, a span that is comparable only to the Crenicichla and Teleocichla genera in the whole of the neotropics.
Those with fewer, larger scales include C. ocellaris, C. orinocensis, C. nigromaculata, C. monoculus, C. kelberi, C. pleiozona, C. melaniae and C. thyrorus, which typically have less than 90 E1 scales. The smaller scales species are typically more slender fish and have more scales in the lateral line series.
Colouration is clearly of importance in the group, with marked differences in both adult and juveniles of different species. However, unfortunately for fishkeepers, colouration can vary according to condition and sex, making identification from colouration alone tricky.
"Each species of Cichla possesses a distinctive adult colour pattern, which is more contrast rich in males, and in most species includes large black blotches on the side lined with silver or golden. These ocellar markings derive from vertical bars and are believed, in the absence of systematic gonadal or field behavious surveys, to represent breeding markings.
"The only exceptional species may be C. piquiti. In C. kelberi, C. monoculus, and C. pleiozona, the breeding colouration is dominated by intensified blotch-like dorsal portions of the vertical bars. Cichla orinocensis and C. mirianae are unique in possessing a series of three distinct ocellated blotches along the middle of the side, formed directly from the juvenile lateral blotches."
More work neededDespite the scale of Kullander and Ferreira's study, they believe that this only partially covers what's required for the genus and that numerous other Cichla species exist:
"We believe the work on a revision of Cichla has just started. Our species accounts include references to samples that cannot be satisfactorily assigned, and some species are still known from a few specimens.
"Huge areas within the geographical range of the genus have not been sampled for fishes. We expect that there may likely exist between 20 and 30 species of Cichla, which require large series of specimens and more extensive sampling to be located and diagnosed. Hopefully, this revision can inspire more efforts in further revising the genus."
Members of the genus are sometimes kept by specialist cichlid experts in very large aquaria. A number of species are offered for sale in the trade, virtually always under the name Cichla ocellaris.
A 2004 study of the Cichla genus provided evidence to suggest that natural hybrids exist between Cichla monoculus and Cichla temensis.
For more information see the paper: Kullander SO and EJG Ferreira (2006) - A review of the South American cichlid genus Cichla, with descriptions of nine new species (Teleostei: Cichlidae). Ichthyological Exploration of Freshwaters, Vol. 17, No. 4, pp. 289-398.