Evolution of the snake visual system

Pipe snake (Anilius scytale)

Understanding the evolution of vision in snakes, such as this pipe snake (Anilius scytale), could improve our knowledge of snake origins and the evolution of the vertebrate visual system

Principal Investigator

Dr David Gower

Project summary

We are asking what the biology of snake vision can tell us about snake evolution and the evolution of vertebrate visual systems.

We use genetic, anatomical, physiological, and ocular media transmission data to do this.

Our team published the first visual pigment (opsin) gene sequences for snakes in 2009, and has been carrying out surveys of visual opsin genes in more than 100 snake species. These surveys cover the major ecological and taxonomic categories of snakes.

Tree Boa

Most of our knowledge of vision in vertebrates is based on studies of mammals, birds and fish - not snakes, like this tree boa (Corallus hortulanus)

 

Why study snake vision?

Vertebrate vision is one of the most studied of all biological sensory systems.  Its anatomical and molecular machinery and genetic underpinning are already well understood.

However, most of this knowledge is based on studies of mammals, birds and fish.

In addition, historical anatomical studies by Gordon Walls and former Museum scientist Garth Underwood demonstrated that the retinal photoreceptor cells (rods and cones) of snakes are exceptionally diverse, implying a great deal of evolutionary change.

Our work on vision in burrowing snakes links to previous work on the evolution of the caecilian visual system carried out by Mark Wilkinson and Samantha Mohun of the Museum's Herpetology Research Group.

Sea snake caught in a net by scientists

To understand how snake eyes adapted to aquatic environments we have sampled sea snakes, such as Hydrophis major

 

Museum staff

Collaborators

Publications

Simões B, Sampaio FL, Jared C, Antoniazzi MM, Loew ER, Bowmaker JK, Rodriguez A, Hart NS, Hunt DM, Partridge JC, Gower DJ (2015) Visual system evolution and the nature of the ancestral snake. Journal of Evolutionary Biology, 28: 1309–1320.

Mohun SM, Wilkinson M (2015) The eye of the caecilian Rhinatrema bivittatum (Amphibia: Gymnophiona: Rhinatrematidae). Acta Zoologica, 96: 147–153.

Mohun SM, Davies WL, Bowmaker JK, Pisani D, Himstedt W, Gower DJ, Hunt DM, Wilkinson M (2010) Identification and characterization of visual pigments in caecilians (Amphibia: Gymnophiona), an order of limbless vertebrates with rudimentary eyes. The Journal of Experimental Biology, 213: 3586–3592.

Davies WL, Cowing JA, Bowmaker JK, Carvalho LS, Gower DJ, Hunt DM (2009) Shedding light on serpent sight: the visual pigment of henophidian snakes. Journal of Neuroscience, 29: 7519–7525.

Funded by

Origins, evolution and futures

We study the Earth's origins and environment, and the evolution of life.

Vertebrates

Determining the diversity, biogeography, taxonomy and phylogeny of vertebrates.

Zoology collections

Our zoology collection has 29 million animal specimens and is rich in voucher, type and historical specimens.