A Revision of African Species of Labeo

Abstract

BEO. G. M. Reid. 1985. J. Kramer, Braunschweig, German Democratic Republic. 322 p., 160 DM (hardbound).-Intended as new look at classification and biology of Labeo, with a detailed survey of all this book provides a good starting point for further study of this biologically poorly known and systematically difficult group of fishes. Its main contribution to systematics at species level. There a three page introductory statement on biology of Labeo, and a telegraphic topical review of biological literature given for each of species, but no attempt has been made to analyze information available and weave it into a comprehensive, comparative review of biology such as Trewavas provided recently for oral-brooding tilapiine Cichlidae of Africa. There virtually no previously unpublished information on food habits, reproductive biology, sensory adaptations, physiology, or behavior. Reid provides an excellent systematic account of species, which he divides into six newly erected species-groups. He states that these groups are not necessarily monophyletic, and that five of them may have their closest relationships with Asian species (p. 54). The forskalii species-group is only one which appears to have no Asian counterpart. This noteworthy, because it by far largest of species-groups (with 19-24 species), has a pan African distribution, and in my opinion one most likely to be polyphyletic. Other features include discussion of lips and other soft parts and their terminology, illustrated by an excellent set of line drawings; illustrations of nearly all of species (most reproduced from earlier publications); keys to species-groups and their included species; and designations of new primary specimens for over 40 nominal species. This a very conservative account of species, in which lies its strength and perhaps its weakness. It clear that many of nominal species were inadequately described and very poorly known, and that many of them are not valid. Reid has cleared up most of this confusion. On other hand, he has chosen to recognize only those species for which he has found irreconcilable morphological differences in preserved specimens. Thus, if morphometric and other differences between samples of two nominal species are accountable for in terms of intraspecific variation documented within some other species of Labeo, samples are considered conspecific even in absence of further supporting data. This questionable ad hoc procedural device (frequently inserted in middle of species descriptions), combined in many instances with examination of only a few small samples, contributes to a substantial reduction in number of species recognized. Thus, at one point Reid states there may be as many as 200 species of Labeo (p. 11), at another type material and general samples have been examined for most of 100 or so species and subspecies previously recognized (p. 6). In actual revision (p. 57-275) only 46 species are recognized. Although many nominal species are placed as junior synonyms, only a few are taken out of synonymy and as valid species; no new species are described. Possibly Reid has given too much attention to old museum specimens (especially types) and not enough to field observations and freshly collected material. He has had some experience with in Nigeria and elsewhere, but none in Congo basin (where species are most numerous). Among topics of particular interest to ichthyologists dealing with fauna are discussion of ecophenotypic variation in L. coubie and other species (resulting in placement of L. pseudocoubie as a junior synonym of L. coubie) and recognition of unusual variegated coloration of L. variegatus as a juvenile characteristic. Reid places L. variegatus as a junior synonym of L. cyclorhynchus. There no discussion of zoogeographic distribution of species because Reid feels that their phylogeny too poorly known for it to be worthwhile. Typographical errors and textual inaccuracies are few. The references cited apparently provide a comprehensive and up-to-date bibliography on biology as well as systematics of Labeo. There an index to nominal species. Reid's notions of species and of zoogeography deserve comment. Regarding species, he states the species in this paper are 'morphological' more than 'biological' entities. I share Rosen's view (1978, 1979) that biospecies concept not a useful analytical tool (p. 12). He also notes that a morphological species concept can lead to recognition as full species of populations which traditionally would be re847