Hannes Geiselbrecht

From EESwiki

The structure and evolution of larval mandibles of decapod crustaceans

In recent times the ideas on decapod phylogeny are yet disussed and change with nearly every new published study. To achieve more definite statements on this subject, it is important to examine new phylogenetically relevant characters and taxa. In case of morphologic and comparing analysis one did mostly focus on the characters of adult animals. Especially in decapoda, where during the ontogeny several planctic larval stages are passed, comparing studies and phylogenetic analysis of larval characters are of special interest.

With the dissection of the manibles of fixed first stage zoea larvae, conducted for the first time in my diploma thesis, and their examination under a scanning electron microscope, a new, so far under comparing aspects undiscussed character, that with no doubt is phylogenetically highly significant, has resulted. This character is to be studied fundamentally and detailed during the dissertation project presented here. Thereby questions on specific feature characteristic of several taxa of the decapoda, questions on the ontogeny of the mandible structure and the evolution of the basic types of mandbiles, as well as questions on the homolgy of certain structures, are to be treated. Main methods will be scanning and transmission electron microscopy as well as 3D visualization by serial sectioning and computer reconstruction.

Supervisor: Roland Melzer