Cephalofoil
The widened head of the hammerhead sharks (Sphyrnidae) is known as the cephalofoil . In contrast to all other types of shark , the head of the hammerhead is strongly extended on both sides directly in front of the gills (prebranchial) and thereby widened.
Expression
It is the central characteristic of this group; At the same time, it is the most important distinguishing feature of the species within the group due to its specific characteristics. This head broadening is between 17 and 33 percent of the total length of the species of the genus Sphyrna, and 40 to 50 percent of the winghead hammerhead shark ( Eusphyra blochii ). The head shape can also be very flattened.
function
It is believed that the widening of the head essentially serves to improve the maneuverability of the shark and improve the field of perception. The eyes and the greatly enlarged nasal pits of these sharks are at the end of the broadening, so that the field that is perceived by these sensory organs is greatly expanded. This applies to the Lorenzini ampoules on the front of the cephalofoil , which in hammerhead sharks not only perceive electrical impulses from potential prey fish, but also currents of the earth's magnetic field and thus serve as an orientation aid during the migrations that are typical for some hammerhead sharks. The mouth lies below the cephalofoil and is usually parabolic in shape.
literature
- LJV Compagno : Sharks of the world. An annotated and illustrated catalog of shark species known to date. Part 2. Carcharhiniformes. FAO Species Catalog for Fishery Purposes Vol. 4. FAO Rome 1984, ISBN 92-5-101383-7 , pp. 538-554 ( full PDF , species portraits )
- Leonard Compagno, Marc Dando, Sarah Fowler: Princeton Field Guides: Sharks of the World . Princeton University Press , Princeton and Oxford 2005, ISBN 0-691-12072-2 , pp. 322-326 .
- Ralf M. Hennemann: Sharks and rays worldwide. Jahr-Verlag, Hamburg 2001, ISBN 3-86132-584-5 , p. 178.