Meeting Abstract

25.6  Monday, Jan. 5  Divergent head shape variation in European eel: how well does skeletal morphology reflect functional demands? IDE, Celine*; DE SCHEPPER, Natalie; DUMONT, Betsy; HERREL, Anthony; ADRIAENS, Dominique; Ghent University celine.ide@ugent.be

The existence of naturally occurring narrow- and broad-headed individuals within the European eel (Anguilla anguilla) populations is since long known. Previous studies demonstrated sexual differences in growth, with females growing faster than males, but which is irrespective of the observed difference in head shape. The apparent divergent head shapes have been related to differences in the diet, where broad-headed eels would feed on bigger and harder prey items. Although some research has been focusing on this dimorphism, very little is still known about how and when this dimorphism arises and what parts of the body plan are involved. What has already been observed is that broad-headed types have larger jaw muscles than narrow-headed ones, where modeling of bite-force suggested higher bite force in broad-headed once. Whether differences observed between the two morphotypes at the skeletal level is a reflection of dealing with differences in mechanical stress during prey manipulation still remains unclear. Using Finite Element Analysis we thus wanted to see to what degree differences in skull morphology between narrow- and a broad-headed eels have an effect on stress distribution when a force is being applied. With this analysis we wanted to find out if the skull architecture in broad-headed eels allows dealing with higher biting forces, and hence is more resistant to mechanical loading force when feeding on harder prey items.