Seehausen 1996 Lake Victoria Rock Cichlids

1 4 Lake Victoria Rock Cichlids 1 2 Lake Victoria Rock Cichlids — taxonomy, ecology and distribution — by Ole Seehausen Institute of Evolutionary and Ecological Sciences, University of Leiden, Netherlands 3 Photo cover: Haplochromis nyererei, territorial male at Makobe Island at a depth of about 6 metres. Photos on pages 132 bottom left, 156 top left, 208 bottom, 244 bottom, and 260 top and bottom by Frans Witte & Els Witte-Maas. All other illustrations by the author. ISBN 90-800181-6-3 Copyright © 1996 by Verduyn Cichlids. All rights reserved. Printed in Germany 4 Contents Preface by Les Kaufman .....................................................................................7 Introduction ........................................................................................................9 Lake Victoria: climate, limnology and history ............................................... 13 Climate and Limnology ............................................................................... 13 Geological history of Lake Victoria ............................................................ 16 The cichlid species flock ................................................................................. 20 The Mbipi, overlooked subflocks like the Mbuna of Lake Malawi? ............. 25 Taxonomy of rock-dwelling cichlids............................................................... 29 Species recognition .................................................................................... 29 Generic taxonomy of Lake Victoria haplochromines ............................... 31 Habitat and ecology of rock-dwelling cichlids — with co-authors A. Samwel-Terry & N. Bouton ......................................... 36 Keeping and breeding of rock-dwelling cichlids ........................................... 44 the aquarium ................................................................................................ 46 water and food ............................................................................................. 48 breeding ....................................................................................................... 50 Identification of rock-dwelling haplochromine cichlids ............................... 58 key to (sub)genera and species complexes .............................................. 61 Introduction to the species discussions ........................................................ 63 Vertical bar Mbipi ........................................................................................ 66 Blue, black and OB, the Neochromis complex of algae scrapers ........... 66 Xystichromis-like epilithic algae scrapers ................................................ 91 The Haplochromis “carp” complex of Xystichromis-like algae scrapers97 In the colours of the rainbow - the Haplochromis nyererei complex ... 100 Large heads - the Haplochromis “deepwater” complex ........................ 125 The Haplochromis “pseudonigricans” complex .................................... 129 Chessboard Mbipi .......................................................................................... 146 Tiny mouths - the H. (Paralabidochromis) “rockpicker” complex......... 146 The H. (Paralabidochromis) “rockkribensis” complex........................... 158 Lobe-lipped cichlids, the H. (Paralabidochromis) chilotes complex .... 167 The H. (Paralabidochromis) chromogynos complex .............................. 175 5 Rock-dwelling species of other lineages Shallow heads and narrow jaws - the Psammochromis lineage .......... 179 Hook-teeth - the Ptyochromis lineage of snail shellers .......................... 190 A mill in the throat - snail crushing haplochromines ............................ 201 “Mgobegobe” - fish eating haplochromines of rocky shores ............... 205 Egg and fry robbers of the Lipochromis lineage .................................... 215 Silver arrows of the “Double stripe” complex ........................................ 227 Teeth like a scalpel - algae scrapers of the Haplochromis lineage ....... 229 Anatomically unspecialized haplochromines of Astatotilapia type ...... 235 Insect eating rock cichlids that cannot be grouped ............................... 244 Frequent intruders from other habitats ......................................................... 250 Astatoreochromis, Oreochromis and Tilapia at rocky shores .................... 258 Non-cichlid rock fishes .................................................................................. 263 Evolution of rock-dwelling cichlids .............................................................. 269 Evolution of habitat specificity and trophic primary radiation .............. 269 A role for sympatric speciation? .............................................................. 271 Secondary radiations by allopatric speciation ....................................... 274 Factors driving divergent evolution in allopatry ..................................... 275 Matrix species ........................................................................................... 277 Conservation of rocky shores and their fish ................................................ 278 Distribution maps ........................................................................................... 281 Tables with taxonomic measurements ......................................................... 291 References ....................................................................................................... 296 Species Index ................................................................................................. 302 6 Preface Professionals and amateur students of economically almost worthless little fishes aquarium fishes both begin with joyous, that started it all by checking out en masse. boundless enthusiasm, but things have a If the shattered remnants of bombed-out way of getting too serious in the pro world, Nature would just fade quietly into the and the fun starts to slip away. For those of realm of paleontology, biologists would be us who work on cichlids from East Africa, able to savor their grief without ever hav- the fun really started wearing thin some- ing to worry about social responsibility. That time in the late 1980s, when it became ap- isn’t how it happened in Lake Victoria. parent that several hundred species of Large chunks of the native fauna just hung cichlid fishes from Lake Victoria that hardly on. A few species are even resurging in anyone had ever seen, might never be abundance now that the famed Nile perch seen again. The world’s second richest is petering out a bit. Included among these lacustrine fish fauna had been destroyed by are the magnificent fauna described in this humans mucking about, reorganizing things book. These may be the most beautiful, so that the lake could produce fish more abundant, and easily located vertebrates to marketable overseas. Hundreds of fishes have escaped the notice of people for this extinct, but then again, hundreds of mil- long. They’ve got the Vietnamese bovids lions of dollars per year pumped into one beat hands down. of the neediest regional economies in the How could more than 200 species of world. A Faustian compromise if ever conspicuous aquatic vertebrates crowd there was one. the shallow waters of the earths’ second Someday there could be an inspiring largest lake, yet go unnoticed through movie or television show made about the most of the 20th century? Perhaps the group of scientists from Africa, who along same way that an equal number could with their colleagues from Europe, the vanish completely from these same wa- Middle East, and North America, got to- ters, within a period of only five or six gether to save their beloved lake from years, yet inspire barely an epitaph save Nile perch, pollution, water hyacinth, and for the sorrow and disappointment of a all the other symptoms of the suffocat- handful who knew and understood. Other ing pressure of humanity. They got the than the African and visiting scientists data, blew the whistle, got into trouble who have borne witness to these events with authorities, worked hard, raised firsthand, nobody could feel the full loss. money, fought over money, sued each But if you are one of these scientists or a other, died, had kids, and generally knowledgeable hobbyist, you should be shared two decades of the joys and trag- seething with anger – anger craving a use- edies of East Africa. Through it all they ful and rewarding outlet. learned a whole lot about each other, and You can’t miss something that you never about life. Meanwhile, the East African even knew was there. But you cannot save Community, left in tatters in the wake of (from our own brutal hand) something that Idi Amin, was awoken from its deep you do not know and love. So, to know and slumber, in good part by embarrassment to love, to celebrate and to share, to gener- (and an embarrassment of international ate interest and funds to where they are funding and publicity) over the state of most needed in conservation: that is what Lake Victoria. Yet, almost lost in the shuf- aquarists can do to save faraway species fle were the haplochromines them- from extinction. But to do so you need a selves... those beautiful, fascinating, and primer, a guide. You need the information. 7 sipping fresh beer through long, long straws, and telling rowdy stories. It is maybe eleven at night and dinner is still on the fire. You hear a hy- ena call, not far away, and then somebody’s dog. And what are people talking about?

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