Fanged fancy: Images of the carp-like fish, Danionella dracula. Unlike the other 3,700-odd species in its group, the males have tooth-like structures, seen in the scanning electron micrographs image in grey (and also the inset image in pink).
Credit: Britz/NHM
There is more than one way to become miniature and the team discovered that Danionella dracula achieved it via a process called 'developmental truncation'. This is when the last stages of the development of an ancestor species have been cut off in its descendant.
In the case of this species, it means that its anatomy resembles that of a seven-millimetre-long larva of the zebrafish, but, unlike the larva, it is sexually mature.
Over time, these changes in developmental events can have a major effect and lead to the evolution of new body characteristics and new species.
"Danionella dracula represents a remarkable example of the evolution of morphological novelties through changes in developmental timing," added Britz.
With the Natural History Museum, London.
