Bull. not. Hist. Mas. (Zool.) 59(1): 33-44 



Issued 24 June 1993 



A review of the serranochromine cichlid fish 

 genera Pharyngochromis, Sargochromis y 

 Serranochromis and Chetia (Teleostei: Labroidei) 



PETER HUMPHRY GREENWOOD 



Visiting Research Fellow, Zoology Department, The Natural History Museum, Cromwell Road, 

 London SW7 5BD; Honorary Associate, J.L.B. Smith Institute of Ichthyology, Private Bag 1015, 

 Grahamstown 6140, South Africa. 



CONTENTS 



Introduction 33 



Methods and Material 34 



Serranoch romine taxonomy 36 



Introduction 36 



The generic or subgeneric status of Serranochromis Regan, 1920, and Sargochromis Regan, 



1920, reconsidered 36 



The genus Chetia Trewavas, 1961 38 



The genus Pharyngochromis Greenwood , 1 979 39 



Conclusion 40 



The phyletic relationships of the serranochromines 40 



Generic key and diagnoses 41 



Acknowledgements 43 



References 43 



Synopsis. Recent taxonomic changes, newly described taxa and groups of taxa, and the introduction of taxonomic 

 characters not previously employed require a revision of the informally recognised, essentially fluviatile group of 

 southern African cichlids, the so-called serranochromines. The genera included in this assemblage are Pharyn- 

 gochromis, Greenwood, Sargochromis Regan, Serranochromis Regan, and Chetia Trewavas. 



Previously, Sargochromis was considered to be a subgenus of Serranochromis, but new evidence indicates that it 

 should be reinstated as a distinct lineage (i.e. genus). The species originally described as Serranochromis 

 (Sargochomis) gracilis should now be transferred to the genus Chetia. Formerly the latter taxon was thought to be 

 monotypic, but it is now expanded to include five species. One of these, Chetia brevis Jubb, had been included 

 tentatively in the genus Astatotilapia, but is now returned to the genus in which it was described originally. 



The monophyletic origin of the serranochromines has still to be established. For that, and other reasons, doubt is 

 cast on the phylogenetic reality of the 'Pharyngochromis - Chetia - Serranochromis' group of endemic species in 

 Lake Malawi. The suggested interrelationships of the serranochromine genera presented below, and based on 

 shared derived characters, cannot, for the same reasons, be considered a truly phylogenetic one. 



INTRODUCTION 



In a paper (Greenwood, 1979) reviewing and reconsidering 

 the generic classification of several cichlid taxa then referred 

 to the genus Haplochromis, an informal group of three 

 genera was recognised on the basis of its constituent species 

 having particular types of squamation and anal fin markings 

 (op. cit: 229-316). The group was, and still is considered one 

 of convenience because no cladistically based hypothesis 

 could be erected to establish the monophyly of its contained 

 genera, viz. Serranochromis Regan, 1920 (with which was 

 incorporated, as a subgenus, Sargochromis Regan, 1920), 

 Chetia Trewavas, 1961, and Pharyngochromis Greenwood, 

 1979. A scheme of possible interrelationships of these taxa, 



suggested earlier by Trewavas (1964), was also discussed in 

 my 1979 paper. 



Recent studies of the genera call for a revision of the 

 group's taxonomy at the generic level, and a reconsideration 

 of their possible interrelationship. For example, the genus 

 Chetia, treated as monotypic by Greenwood, (1979) is now 

 thought to contain five species (Balon & Stewart, 1983; 

 Greenwood, 1984, 1992, and below, p. 38), certain problems 

 regarding the generic classification of several Angolan hap- 

 lochromine species have been clarified (Greenwood, 1979, 

 1984 & 1992), new ideas on the supposed relationship of 

 Serranochromis and Sargochromis have been put forward by 

 Lippitsch (1991: 99-100), and Eccles & Trewavas (1989: 21) 

 have formally recognised, amongst the endemic genera of 

 Lake Malawi, a large assemblage of species which they 



