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[[ Parananochromis Greenwood ZBK ]]

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 ZBK and Nanochromis ZBK . 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 ZBK and most of the species currently included in Parananochromis ZBK was discussed by Thys van den Audenaerde (1968), and later by Greenwood (1987) who diagnosed Nanochromis ZBK 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 ZBK , 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 ZBK . In fact two of the new taxa described herein ( P. brevirostris ZBK and P. ornatus ZBK ) display an elevation of the upper lateral line (albeit not to the extent found in Nanochromis ZBK ), a reduction of infraorbital elements from five to four ( Nanochromis ZBK has a single tubular element), and the possession of a low crest on the supraoccipital. In these features P. brevirostris ZBK and P. ornatus ZBK display a trend towards the derived Nanochromis ZBK condition.

Final resolution of the phylogenetic status of the genus Parananochromis ZBK (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 ZBK , 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.


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