Science News
from research organizations

Colorful View For First Land Animals

Date:
October 27, 2007
Source:
BioMed Central
Summary:
When prehistoric fish made their first forays onto land, what did they see? According to a new article, it's likely that creatures venturing out of the depths viewed their new environment in full color.
Share:
FULL STORY

Most vertebrate classes have pigments which are sensitive to one or more of the light wavelengths shown (long wavelength sensitive (lws) through short wavelength sensitive 1 (sws1)). The DNA of the five visual pigment genes in the retinas of lungfish reveals that these have more in common with four-legged vertebrates than with fish retinas.
Credit: Image courtesy of BioMed Central

When prehistoric fish made their first forays onto land, what did they see? According to a study published in the online open access journal, BMC Evolutionary Biology, it's likely that creatures venturing out of the depths viewed their new environment in full colour.

A team led by Helena Bailes at the School of Biomedical Sciences, University of Queensland, Brisbane, Australia, analysed retinas from Australian lungfish (Neoceratodus forsteri), thought to be the closest living relative to the first terrestrial vertebrates. The researchers then compared these to other fish and amphibian retinas. The DNA of five visual pigment (opsin) genes in the retinas of lungfish reveals that these have more in common with four-legged vertebrates (tetrapods) than with fish retinas.

Although lungfish mainly take in oxygen through their gills like most fish, they can also breathe air if water quality is poor. Lungfish were previously thought to have poor eyesight due to their small eyes, low spatial resolving power, sluggish behaviour in captivity and ability to detect prey using electroreception. N.forsteri inhabits a brightly lit, shallow freshwater habitat similar to the environment from which terrestrial evolution probably occurred. This prompted the team to investigate the complement of opsins expressed in N. forsteri, to trace photoreception's evolution in ancestral tetrapods.

The study paves the way for behavioural work with lungfish to see if they can discriminate between objects based on colour.

"The genus Neoceratodus, of which N. forsteri is the sole survivor, is found in the fossil record from the Lower Cretaceous period 135 million years ago and therefore N. forsteri lays claim to being the oldest surviving vertebrate genus," says Bailes. "The visual system of N. forsteri may represent an evolutionary design most closely reflecting that present just prior to the emergence of land vertebrates in the Devonian period."

Article: Helena J Bailes, Wayne L Davies, Ann EO Trezise and Shaun P Collin, Visual pigments in a living fossil, the Australian lungfish Neoceratodus forsteri, BMC Evolutionary Biology (in press)


Story Source:

Materials provided by BioMed Central. Note: Content may be edited for style and length.


Cite This Page:

BioMed Central. "Colorful View For First Land Animals." ScienceDaily. ScienceDaily, 27 October 2007. <www.sciencedaily.com/releases/2007/10/071025080917.htm>.
BioMed Central. (2007, October 27). Colorful View For First Land Animals. ScienceDaily. Retrieved May 23, 2017 from www.sciencedaily.com/releases/2007/10/071025080917.htm
BioMed Central. "Colorful View For First Land Animals." ScienceDaily. www.sciencedaily.com/releases/2007/10/071025080917.htm (accessed May 23, 2017).

RELATED STORIES