Alexandra Schiviz

Comparative Studies on the photoreceptor topography
of Hoofed Animals (Artiodactyles) and the African Elefant

In her thesis, Alexandra Schiviz has studied the distribution of short and medium wavelength sensitive cone photoreceptors of hoofed mammals.
For this task she has been collecting tissues from in 23 ungulate species including some during a visit to a licensed hunting farm in Namibia as well as from specimens delivered to the Dept. of Veterinary Pathology (Dr. Anna Kübber-Heiss, Veterinary University Vienna) from Austrian zoos and animal parks.

The wide range of species - yet not accessible from any other mammalian group - has allowed her draw conclusions on the general design of the artiodactyle visual system and to dedect significant correlations of photoreceptor topography to life styles and particular habitats.

In addition she has taken the opportunity to study retinas from
two African elephants recently deceased at Schönbrunn Zoo.

Reference:

Schiviz, A. N., Ruf, T., Kuebber-Heiss, A., Schubert, C., & Ahnelt, P. K. (2008). Retinal cone topography of artiodactyl mammals: influence of body height and habitat.
J Comp Neurol, 507(3), 1336-1350.

Above: Outline of the Bactrian camel's retinal wholemount with major blood vessels.
The typical L-shape of higher density areas in the map of mediumwavelength cones is indicated.

Below: Correlation of topographic weightings
with eye level and habitat types. Note similarities between Giraffe and mountainous species (Barbary goat)