40 



P.H. GREENWOOD 



considered either as a superspecies composed of several 

 topospecies or as an assemblage of evolutionary species, but 

 no clear-cut features allowing a formal taxonomic division of 

 the taxon can be identified (see Discussion in Greenwood, 

 1992). 



Anatomically and morphologically, Pharyngochromis is 

 the least derived member of the serranochromines. Its sole 

 autapomorphic feature is the higher position occupied by the 

 posterior scales of the upper lateral-line series relative to the 

 base of the dorsal fin (see Greenwood, 1992). The last five to 

 seven (rarely four or eight) pored scales in that series are 

 separated from the dorsal fin base by only one large and one 

 much smaller scale. In the other serranochromine genera 

 only the last one or two pored scales are separated from the 

 fin base in this way, the other posterior scales having at least 

 two large scales of equal size interposed between them and 

 the fin base (see Greenwood, 1979 & 1992). 



In most P. acuticeps specimens (from all localities) the 

 lower pharyngeal bone is slightly enlarged, and some of its 

 median row teeth, which are always coarser than their lateral 

 congeners, have molariform or submolariform crowns 

 (Greenwood, 1992, fig. 7). There is, however, considerable 

 individual variability in the degree to which this bone is 

 enlarged and its teeth are molarized. In these respects, P. 

 acuticeps resembles certain Sargochromis species, particularly 

 S. coulteri (Bell-Cross) and S. greenwoodi (Bell-Cross). But, 

 since the two genera differ in several other features, I would 

 consider this resemblance to be homoplastic and not, as 

 Trewavas (1961: 9) suggested, one of phylogenetic signifi- 

 cance. 



If the serranochromines are a monophyletic lineage, (see 

 p. 41) their recent common ancestor could well have resem- 

 bled the extant Pharyngochromis acuticeps, except for the 

 incipient hypertrophy of the pharyngeal jaws in the latter. 



Pharyngochromis acuticeps has a very wide distribution 

 which includes the Zambezi and Save-Runde river systems, 

 the Okavango river and its delta swamps, Lake Calundo, the 

 Lucala river (Quanza drainage) and some unidentifiable 

 localities in Angola. Records of the species (as Haplochromis 

 darlingi) from the Limpopo river system (Jubb, 1967, 

 repeated in Greenwood, 1979) are now known to be errone- 

 ous and probably based on the misidentification of small 

 Chetia flaviventris specimens. 



A revised generic diagnosis of Pharyngochromis is given in 

 Greenwood (1992:48) and on p. 42 below. 



CONCLUSION 



The phyletic relationships of the 

 serranochromines 



The difficulties encountered in determining both the inter- 

 and intrarelationships of these fishes were discussed in two 

 previous papers (Greenwood, 1979 & 1992), as was Trewa- 

 vas' earlier (1964) tentative scheme of their relationships. 

 Basically the problem lay, and still lies, in establishing 

 whether or not the group is of monophyletic origin. 



One of the two features unifying the serranochromines, the 

 non-ocellate anal fin markings, is probably a plesiomorphic 

 character, perhaps representative of a stage in the evolution 

 of true ocelli and one in which the markings, unlike true 

 ocelli, are not confined to males (Greenwood, 1979; Oliver, 



1984). However, the possible function of anal maculae as 

 egg-dummies (sensu Wickler, 1962; 1963), or even if they 

 play any part in reproductive behaviour (Hert, 1989), have 

 yet to be determined. There is also the possibility that 

 non-ocellar anal markings have evolved more than once 

 within the haplochromine cichlids (sensu law), as their pres- 

 ence in species of Thoracochromis (Greenwood, 1979, 1984) 

 could suggest. (Alternatively, Thoracochromis and the serra- 

 nochromines may be more closely related than other morpho- 

 logical and anatomical evidence would indicate.) In this 

 context, Eccles & Trewavas', (1989: 27) obervations on three 

 species of the endemic Malawi genus Aulonocara are perti- 

 nent. One of these species has simple spots, a second has 

 spots surrounded by a contrasting border, and the third no 

 markings at all, although the fin has a pale border. Since 

 Aulonocara has a number of distinctive anatomical autapo- 

 morphies, this situation certainly suggests that not only have 

 different kinds of anal fin markings evolved more than once 

 but have done so within a single genus. 



Another aspect of the problem involving phylogeny and 

 anal markings is Oliver's (1984: 108) suggestion that hap- 

 lochromines with multiple non-ocellar spots, together with 

 those having true ocelli, comprise a monophyletic assemblage 

 whose members are more closely related to one another than 

 to any species with what he considers to be the pleisiomorphic 

 condition of anal maculae, namely spots indistinguishable 

 from those on the other unpaired fins, especially the dorsal 

 fin. That hypothesis has yet to be tested by the identification 

 of suitable congruent and derived features characterizing the 

 two supposed lineages, and raises questions about the signifi- 

 cance of the seemingly unique anal marking of Pseudo- 

 crenilabrus species (Greenwood, 1989). 



All in all, the current evidence for anal fin markings being 

 of value in reconstructing phylogenies is not encouraging, 

 particularly at the taxonomic levels under consideration here. 

 For that reason I cannot agree with Eccles & Trewavas' 

 (1989) use of the feature as grounds for suggesting a close 

 relationship between the fluviatile serranochromines and 

 most of the endemic haplochromines of Lake Malawi. While 

 agreeing that non-ocellar anal spots are plesiomorphic fea- 

 tures, these authors believe that the absence of true ocelli in 

 the two groups ". . .combined with the geomorphological 

 history of the region . . . may be accepted as evidence for the 

 relationship of the Malawian group of species with the 

 haplochromines of the Zambezi area" {i.e., with Serrano- 

 chromis, Sargochromis and Pharyngochromis; Chetia has not 

 been recorded from the Zambesi system). Certainly the 

 similarity in anal fin markings would seem to support the 

 intuitive feeling that the two groups could be related (see 

 p. 34), and thus encourage a search for other characters to 

 confirm or refute that impression, but in itself I would not 

 rate it as 'evidence'. 



The second morphological character used to define the 

 serranochromines, i.e. cycloid scales above the lateral line 

 and a preponderance of such scales below that level, is, I 

 would argue, a derived condition (Greenwood, 1979; see also 

 Oliver, 1984; Lippitsch, 1991). Nevertheless, it is not clearly 

 an autapomorphic feature of the serranochromines. For 

 example, in the Lake Malawi haplochromines mentioned 

 above, there is also a marked reduction in scale ctenoidy, but 

 here, although scales above the lateral-line, like those in the 

 serranochromines, are cycloid, the ctenoid scales occurring 

 below that level are confined to the posterior part of the body 

 and not the anterior part as in serranochromines. In a 



