Swimming and thermoregulation in sharks and tuna
Thunniform swimming depends on a large, lunate tail that is joined to the rest of the body via a narrow peduncle. Whilst the tail flicks backwards and forwards, so propelling the animal, the rest of the body hardly moves sideways.

Bioluminescence
Flying through the air on a summer's evening or sparkling in the ocean you may see magical flashes of light that signal some of nature's most enchanting creatures, those that are bioluminescent.

Swimming and thermoregulation in sharks and tuna
Thunniform swimming depends on a large, lunate tail that is joined to the rest of the body via a narrow peduncle. Whilst the tail flicks backwards and forwards, so propelling the animal, the rest of the body hardly moves sideways.

Why emit light? The many functions of bioluminescence
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Bioluminescence
Flying through the air on a summer's evening or sparkling in the ocean you may see magical flashes of light that signal some of nature's most enchanting creatures, those that are bioluminescent.

Cichlids
Cichlids are one of the cause celebré of evolution, and rightly so because these freshwater fish show a remarkable diversity and exemplify many key aspects of adaptive radiation. But why so successful? The answer lies in the versatility of the jaws (and yes, they are convergent).

Lateral line system in fish and other animals
Some cavefish are completely blind, so how do they manage to navigate through their environment with astonishing ease?

Pufferfish (and inflation)
Pufferfish are some of the most extraordinary fish to have evolved, especially because of their capacity to swallow water and inflate themselves to something like a football. Not only that but some representatives can be deadly to the unwary diner...

Suction feeding in fish, amphibians, reptiles and aquatic mammals
Probably everyone is familiar with the walrus, but did you know that it generates a vacuum in its mouth to suck clams out of their shells? And this is just one example of suction feeding, the feeding mode typically used by bony fish…

Teeth in aquatic reptiles
Aquatic reptiles tend to display one of three dentition types, well adapted to either seize and slice large vertebrate prey, pierce and gouge slippery fish, or entrap small prey such as crustaceans.

Durophagy (hard prey-eating) in fish
Plenty of animals have an extraordinary capacity to crush hard prey and this has evolved independently many times in the vertebrates. If you suspect it is a durophage, watch your fingers!

Mammal-like placentation in skinks (and fish)
“Only two types of vertebrates [have] evolved a reproductive pattern in which the chorioallantoic placenta provides the nutrients for fetal development. One is [...] the eutherian mammals […], and the other, a few lineages of the family Scincidae.” A.F. Flemming (2003) J Exp Zool 299A 33-47

Viviparity in sauropterygians
“The [fossilised] embryos are mostly in articulation and their distribution on each side indicates that female Keichousaurus hui had a pair of oviducts as in ichthyosaurs and many extant lizards.” Y. Cheng et al. (2003) Nature vol. 432, p.383

Viviparity in mosasaurs
An exceptionally preserved gravid female of the aigalosaur Carsosaurus contains at least at least four advanced embryos […] Their orientation suggests that they were born tail-first […] to reduce the possibility of drowning, an adaptation shared with other other highly aquatic amniotes” M.W. Caldwell & M.S.Y. Lee (2001) Proceedings of the Royal Society of London B, vol. 268, p.2397

Viviparity in ichthyosaurs
“For me, the fossil is a transporting piece of evidence. It shows a female ichthyosaur that died late in pregnancy or perhaps while giving birth; the baby was entombed with its mother in the mud.” J. Rennie (2000) Scientific American, vol. 283(6), p.8

Viviparity in lizards, snakes and mammals
“In over 100 lineages of […] squamates, the oviduct has been recruited for viviparous gestation of the embryos, representing a degree of evolutionary convergence that is unparalleled in vertebrate history.” D. G. Blackburn (1998) Journal of Experimental Zoology, vol.282, p.560

Electric fish: insights into convergence
Ever seen an electric eel in an aquarium? Don’t dare putting your hand in the tank...

Dolphin communication, cognition and sociality
Dolphins are one of the most intriguing sources of evolutionary convergence, having cognitive abilities that seem to find many parallels in the great apes, and rather remarkably even extend to tool use.

Electroreception in fish, amphibians and monotremes
From an evolutionary point of view, electroreception is particularly intriguing as a sense modality that has been repeatedly lost and reinvented again.