Parananochromis Greenwood

Anton Lamboj & Melanie L. J. Stiassny, 2003, Three new Parananochromis species (Teleostei, Cichlidae) from Gabon and Cameroon, Central Africa., Zootaxa 209, pp. 1-19 : 16-17

[[ Parananochromis Greenwood ]]

Discussion. The combination of the possession of four openings of the sensory canal system in the lachrymal (versus 5), 12 circumpeduncular scales (versus 14-16), and a Haplochromis-type(versus a Tilapia-type) of neurocranial apophysis, characterizes the two genera, Parananochromis and Nanochromis . Greenwood (1987) considered the latter two features as derived within the chromidotilapiine lineage and therefore as evidence of a sistergroup relationship between the two genera. The distinction between Nanochromis and most of the species currently included in Parananochromis was discussed by Thys van den Audenaerde (1968), and later by Greenwood (1987) who diagnosed Nanochromis on the basis of a number of derived features (e.g., two bones in the infraorbital series, at least the last 3 or 4 pored scales of the upper lateral line contiguous with dorsal fin base, and a low supraoccipital crest). However, no such diagnosis was presented for Parananochromis , which remains uncharacterised by uniquely derived features and possibly therefore a paraphyletic assemblage. In the course of the present study we have found no evidence that could be used to support the monophyly of Parananochromis . In fact two of the new taxa described herein ( P. brevirostris and P. ornatus ) display an elevation of the upper lateral line (albeit not to the extent found in Nanochromis ), a reduction of infraorbital elements from five to four ( Nanochromis has a single tubular element), and the possession of a low crest on the supraoccipital. In these features P. brevirostris and P. ornatus display a trend towards the derived Nanochromis condition.

Final resolution of the phylogenetic status of the genus Parananochromis (and indeed the other chromidotilapiine genera currently lacking phylogenetic diagnoses) must await a thoroughgoing phylogenetic analysis, a task that is beyond the scope of the current paper. For the time being, and as a pragmatic approach for the purposes of species description, we have assigned the three new species to Parananochromis , while alerting readers to the possibility that generic reassignment may be necessary once a fuller understanding of the generic limits and relationships among chromidotilapiines is gained.