Diploma Thesis

"Computer aided 4D-reconstruction of the flatfish head during metamorphosis in the sole (Solea solea)"

Computergestützte 4D-Rekonstruktion des Plattfischkopfes während der Metamorphose am Beispiel der Seezunge (Solea solea, Linnaeus, 1758)

The metamorphosis of flatfishes (Pleuronectiformes) is characterized by numerous morphological changes and asymmetries in the head region - the most striking of them is the migration of one eye to the opposite body side (zenithal or "upper" side). With increasing lateral compression of the body and a 90°-turn of the nadiral side towards the bottom entails a change form pelagic to benthic way of life.

In this study the development of the right-eyed sole Solea solea (Soleidae) is investigated using five selected larval stages. By means of scanning electron microscopy, semithin section series and modern 3D-visualization software (Amira) the following organ systems are displayed: integument, side channel system, chondrocranium, osteocranium, jaw muscles, brain, olfactory organ, eyes, optical nerves, eye muscles and the labyrinth organ.

A detailed morphological analysis is facilitated by the comparison of the "original" histological sections and freely rotable 3D-visualizations of any organ system. Developmental events as well as occurring asymmetries are described, displayed and analyzed semi-quantitatively (morphometry).

In the course of eye migration no solid obstacles are found; the shape and positioning of the labyrinth organ do not change during metamorphosis despite of the high degree of asymmetry in the frontal parts of the head; and contrary to pervious statements no transient asymmetry of any brain part is observable. The new data are compared with published knowledge and discussed critically.