2. Behavioral Biology TALKS - Deutsche Zoologische Gesellschaft

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����219 Stefanie Bublak
All good things come in fours? Description of a prospective fourth olfactory organ in
Clawed Frogs (Genus Xenopus)
Authors: Stefanie Bublak 1 , Christine Nowack 1
Affiliation: 1 Department of Zoology/Developmental Biology, University of Kassel
Frogs of the Genus Xenopus (Family Pipidae, tongue-less frogs) ordinarily possess
three different olfactory systems: the main olfactory organ and the vomeronasal
organ of most tetrapods, as well as a so called middle chamber epithelium (or waternose),
a structure specific for pipid frogs. These three systems differ in terms of their
position within the nasal cavity, their ultrastructure, expression of olfactory receptor
molecules, and very probable also their functional background.
In the present study the morphology of the nasal cavity of Xenopus borealis (Marsabit
Clawed Frog), a species that is closely related to the well examined model organism
Xenopus laevis, was investigated for the first time. Histological cross sections of the
nasal region were analysed by light microscopy, as well as additional series sections
in horizontal and sagittal plane. In general, the nasal structures of X. borealis
resemble the situation found in X. laevis, including the distribution of the sensory
epithelia of the three common olfactory organs.
Surprisingly in sections of the palatal orientation we were able to observe a
presumably sensory structure within the main nasal cavity, which has not been
described so far.
A vertically oriented groove of sensory epithelium, separated from the main olfactory
epithelium by connective tissue, is located in the caudolateral area of the main
cavity.
The cytoarchitecture within this groove as well as the presence of subepithelial
pigmented cells strongly indicate an olfactory function of this structure.
Further investigations of the ultrastructure, the neuronal connections and the
occurrence of olfactory receptor molecules are needed to confirm our histological
results. Another important step will be to find out if this is a species-specific finding,
or if the structure is also developed in other frogs.
����220 Annekathrin Junk
Deviant anatomy of the olfactory system in Madagascan mantellid frogs
Authors: Annekathrin Junk 1 , Miguel Vences 1 , Christine Nowack 1
Affiliation: 1 Department of Zoology/Developmental Biology, University of Kassel
Members of the family Mantellidae (Anura, Amphibia) inhabit one of the largest
islands of the Indian Ocean, Madagascar. Up to now, the anatomy of the nasal
cavities of these frogs has not been investigated. In the present study, the intranasal
structures of selected members of the Mantellidae were examined histologically.
Commonly the paired nasal cavity (cavum nasi) of anuran amphibians consists of a
main nasal cavity, and a complex structured set of paranasal sinuses. Within the main
cavity, the sensory epithelium of the main olfactory organ is located, while the
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