MSc Student (Adv. Harald Ahnelt)

Unit for Theoretical Biology, Department of Evolutionary Biology
University of Vienna

Abstract

The term “hyperostosis” describes a phenomenon of hyperossification which leads to an excessive bone growth. The structures on affected bone are described as gall-like swollen globes. It appears in many vertebrate taxa whereby in most tetrapods it is caused by pathological reasons. In humans it can be caused by various anaemias or disorders. But in fishes, specifically in Teleostei, it is often non-pathological and is termed “Fish-Hyperostosis” (FH). The affected species show no change in behaviour or in their health statuses. FH is long known (Worm, 1655) but still many questions seem to be unanswered. Generally, this phenomenon occurs with age and growth and therefore has been described just from adult specimens.

This study has two focuses. Firstly, based on literature, an extensive review of fish taxa (families, genera and species) with fish hyperostosis will be conducted. Afterwards all bones affected with hyperostosis will be classified in their functional units (e.g. neurocranium, oral jaws or pectoral girdle) of the skeleton and will be ranked in their concernment. Secondly, in collaboration with the Natural History Museum Vienna, skeletons of hyperostotic fishes will be described in comparison with skeletons of unaffected conspecifics. Whole-mount and disarticulated skeletons of Carangidae, Ephippiidae, Sciaenidae and Zeidae will be investigated. Additionally, radiographs of ethanol preserved specimens and microCT’s of single bones will be included.