Comparative morphology of labial cartilages in sharks

Published on
18. November 2020

Comparative morphology of labial cartilages in sharks (Chondrichthyes, Elasmobranchii)

C. Klimpfinger & J. Kriwet

ABSTRACT:

During the last years, feeding mechanisms of sharks have been documented mainly based on their stomach contents supplemented by video footages of feeding behaviours in some species. Rare kinematic analyses of shark jaws contributed additionally to our knowledge. However, not all structures important to prey capture in sharks have been investigated yet. Here, we summarize the current knowledge about labial cartilages in sharks and compare them on a morphological base. Labial cartilages are considered a plesiomorph character found in extinct and extant species and their number and size varies a lot between species. We identified labial cartilages in representatives of 27 from 36 shark families and detected different numbers, sizes and forms of labial cartilages, as well as differing positioning along the jaws. The morphology of labial cartilages can help to identify suction-feeding in sharks and to estimate the quality of the suction generated by a species. We were able to summon different shark taxa according to their morphology and positioning of labial cartilages into eight groups, which we consider morphological modules. To determine if these modules bare a phylogenetic signal further testing with rigorous methodologies and more shark species as well as batomorphs needs to be done. This study therefore only can represent a first starting point providing future research pathways.

The European Zoological Journal, 87:1, 741-753, DOI: 10.1080/24750263.2020.1844323

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