Sea snakes potentially regained ability to see color: Research

The annulated sea snake, a species of venomous snake found in ocean waters around Australia and Asia, appears to have evolved to see an extended palette of colours after its ancestors lost that ability in response to changing environments, according to a new paper published in Genome Biology and Evolution by Oxford University Press.
Color vision in animals is primarily determined by genes called visual opsins. While there have been multiple losses of opsin genes during the evolution of tetrapods, the emergence of new opsin genes is extremely rare.
This study used published reference genomes to examine visual opsin genes across five ecologically distinct species of elapid snakes. The history of elapids, a family of snakes that includes cobras and mambas in addition to the annulated sea snake, presents an opportunity to investigate the molecular evolution of vision genes.
Researchers here found that the annulated sea snake possesses four intact copies of the opsin gene SWS1. Two of these genes have the ancestral ultraviolet sensitivity, and two have evolved a new sensitivity to the longer wavelengths that dominate ocean habitats. The study’s authors believe that this sensitivity may provide the snakes with better color discrimination to distinguish predators, prey and/or potential mates against colorful marine backgrounds.