The cichlid, a small fish, has one of the most incredible visual systems known — which allows it to adapt to differently colored environments.
While some of the fish were left alone, others were exposed to what looked like a predator — a doll version of a guppy - eating fish called a pike
cichlid.
And
cichlid mothers who spend weeks with their mouths full of eggs, waiting for them to hatch.
But even seasoned
cichlid researchers like myself are still being surprised by new evidence of their diversity.
The first
cichlid was described in 1864 after a botanist on one of David Livingstone's expeditions sent back some dried skins to the Natural History Museum in London for identification.
Most species of
cichlid live in three lakes in Africa's Great Rift Valley.
It has taken the lake
cichlids just 100 generations and as many years to evolve an entirely new physical feature: very fat lips.
Over a remarkably short period,
cichlids in the African great lakes have spawned hundreds of new species, with an enormous range of characteristics.
But
cichlids are profoundly fascinating for biologists - they have achieved the most rapid and extensive diversity known to science.
If our estimates are correct, there could be twice as many
cichlid species in these three lakes as there are freshwater fish in the whole of Europe and North America.
«I don't necessarily care what the taxonomic rank would be of the units I'm studying,» says Hey, whose current research involves
cichlid fish in Lake Malawi.
Neolamprologus obscurus is a highly sociable species of
cichlid found only in the southern reaches of Lake Tanyanika.
One study attributed higher mental functions to fish, presenting evidence that African
cichlids can reason inferentially.
«But what is interesting within
cichlids, which is this group of very diverse fishes, is that they can express different sets of these seven genes.
And the descendants of that fish, now called
cichlids, continue to swim the fresh waters of both Africa and South America.
The opsin genes of Amazonian
cichlids.]
African
cichlids, whose visual systems are well studied, evolved in fairly clear, calm, blue lakes with plenty of sunlight.
Cichlids have some of the most incredible visual systems known.
When researchers placed African
cichlid fish in a tank, the fish showed identical aggressive behavior whether their opponent was their reflection or another fish across a clear barrier, ramming and biting at both.
Cichlid fishes have undergone a mind - boggling degree of speciation.
Moreover, the results are consistent with molecular genetic data relating to the ongoing diversification of the family in the Great Lakes region of East Africa, which have indicated that hybridization between members of related species or even genera has played a major role in
cichlid speciation.
But the Lake Victoria
cichlids far surpass Darwin's finches in the astonishing speed with which they diversified: the more than 500 species that live there and only there today all evolved within the past 15,000 to 10,000 years — an eyeblink in geologic terms — compared with the 14 finch species that evolved over several million years.
Like Charles Darwin's famous finches, which evolved a wide range of beak shapes and sizes to exploit the different foods available in the Galápagos Islands,
these cichlids represent a textbook example of what biologists term an adaptive radiation — the phenomenon whereby one lineage spawns numerous species that evolve specializations to an array of ecological roles.
«Our fossil supports the hypothesis that hybridizations played a more prominent role in
cichlid speciation than was once thought — and that diversification of the cichlids now endemic to the lake did not begin in the lake itself,» Reichenbacher says.
Unfortunately, fossil specimens that could help to trace earlier phases of
cichlid evolution are quite rare, and most are poorly preserved and / or fragmentary.
Now scientists around Ludwig - Maximilians - Universitaet (LMU) in Munich paleontologist Professor Bettina Reichenbacher have described a new fossil
cichlid discovered in Upper Miocene strata in East Africa, which provides new insights into the evolutionary history of the group.
«This combination of characters is particularly interesting, because molecular geneticists have shown that many of
the cichlid species in Lake Tanganyika possess «mosaic» genomes — made up of genetic material derived from non-related species.
The basin now occupied by Lake Tanganyika came into being at least 5.5 million years ago, and it has been assumed that the species radiation that gave rise to the striking diversity of
cichlids in the lake was triggered by its formation.
The new fossil displays a striking «mosaic - like» set of characters, combining traits that are typical for three distinct
cichlid groups found in Lake Tanganyika today.
«This unique resource has made it possible for the first time to place a new fossil species securely within the phylogeny of African
cichlids.
Male
cichlid fish battle for stretches of lake - bottom territory where females lay their eggs.
When a male
cichlid fish captures a piece of prime real estate, his gonads go wild.
This dataset is based on the painstaking analysis of X-ray photographs of the skeletons of 763 individuals belonging to 227 modern
cichlid species.
Indeed, our analysis shows it to be a member of the most ancient
cichlid lineage that contributed to the so - called East African Radiation, a spectacular burst of diversification that has given rise to a huge variety of species,» Reichenbacher explains.
However, in cooperation with Dr. Ulrich Schliewen (Zoological State Collections, Munich), Reichenbacher and her team have assembled a unique database on the morphology of present - day
cichlids, in which all the lineages found in Lake Tanganyika are represented.
They don't signal their ascent from beta to alpha status by turning bright blue, as do males from one species of African
cichlid fish.
Chernoff has compiled a staggering collection so far, including, at top left, collection jars used to maintain specimens in alcohol; facing right and up, two red - eyed piranhas; far right, a fish head and the skin of an Arapaima gigas, South America's largest freshwater fish; across the bottom,
cichlid, tetra, and aruanã skeletons.
Lake Malawi, shared by Malawi, Mozambique, and Tanzania, is home to at least 500 species of
cichlids, all of which probably took less than a million years to evolve from a common ancestor.
Related Sites
The Cichlid Fishes of Lake Malawi, Africa Patrik Bylund's page on Malawi cichlid evolution
With a graduate student, Kapa Lenkov, Fernald tested this directly in
cichlids raised in his Stanford lab.
A new study shows that
cichlid fish reared in larger social groups from birth display a greater and more extensive range of social interactions, which continues into the later life of the fish.
Fernald studies Astatotilapia burtoni, one of the hundreds of
cichlid fish species inhabiting Lake Tanganyika in eastern Africa, because of the unique ways they have evolved over time.
In a study published in PLoS ONE, researchers from Stanford report that social status in
cichlid fish may be regulated by DNA methylation.
For the study, published this week in the journal The American Naturalist, researchers used the Neolamprologus pulcher (N. Pulcher) breed of
cichlid, primarily found in Lake Tanganyika — the great African freshwater lake that feeds into the Congo River.
As perhaps with any social creature, Fischer points out that higher social competence and the ability to conform to social hierarchies may well stand
the cichlids in good stead in later life:
A cichlid in Africa's Lake Tanganyika uses patterns of facial stripes to distinguish individuals and keep tabs on them
The angelfish (Pterophyllum scalare) is a colorful
cichlid native to the Amazon Basin, but is now found in aquariums around the world because of its popularity in the pet trade.
The extraordinary diversity of
cichlid fishes challenges entrenched ideas of how quickly new species can arise
Cichlids are central to evolutionary research.
Incipient species of African
cichlid fish have divergent genomic islands associated with mate choice.