Labial fold

Labial folds are flaps of skin that form in the area of ​​the corners of the mouth of cartilaginous fish and are separated from the surrounding tissue by labial furrows . As a rule, the labial folds are supported by inner labial cartilages in the corner of the mouth, which are formed in pairs.

Modern sharks usually have two pairs of upper labial cartilages (anterodorsal and posterodorsal) and one pair of lower cartilage (ventral), but this can vary widely and both the cartilage and the labial folds and furrows can be completely absent. Accordingly, they represent an important taxonomic characteristic for the differentiation and classification of cartilaginous fish, especially sharks .

literature

• Leonard Compagno , Marc Dando, Sarah Fowler: Sharks of the World . Princeton Field Guides, Princeton University Press , Princeton and Oxford 2005, ISBN 0-691-12072-2 , p. 331.