A cephalic sensory system with a suggested mechanoreceptive function in two pentanchine Scyliorhinidae (Elasmobranchii)

Enderes C., Bartsch P.

Date de parution: septembre 2009
Volume: 33
Number: 3
Pagination: 229-240
Editeur: Société Française d'Ichtyologie
doi: https://doi.org/10.26028/cybium/2009-333-006
Résumé

The heads of three scyliorhinid sharks (Scyliorhinus canicula, Galeus melastomus, Apristurus aphyodes) were investigated histologically in order to clarify the anatomy of the electroreceptive system (ampullae of Lorenzini). Complexes of ampullae of Lorenzini were digitally 3D-reconstructed according to section series and superficial pore patterns belonging to the complexes were mapped. Neurocranial structures were reconstructed with computertomography. These investigations revealed that not all pore fields on the surface of the head in G. melastomus and A. aphyodes (Pentanchinae) are part of the electroreceptive system as generally assumed: mediorostral pore fields dorsally and ventrally as well as preorbital and supralabial pore fields in both species are part of a subdermal system of shallow solitary grooves, surrounded by the same dense connective tissue as the canalicular mechanoreceptive lateral line. Histological sections show digitiform protuberances and maculae similar to neuromast organs of the epithelia in the groove system in G. melastomus. Accordingly, histology rather indicates a mechanoreceptive function. The exact function or biological role and the phylogenetic significance of this elaborate system in two pentanchine catsharks are by no means clear yet. A similar groove system was found in A. fedorovi, A. herklotsi and G. murinus. In S. canicula (Scyliorhininae) no comparable grooves or pores are found.

Mots-clés: Apristurus - Cranial pore fields - Galeus - Histology - Lateral line - Morphology - Pentanchinae - Scyliorhinidae
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