Alan Pradel, Vincent Luccisano, François Clarac, Roman Khonsari, John Maisey, V. Trudeau, G. Somoza, C. Awruch, Hector Botella, Léo Zevallos-Valdivia, Carlos Martinez-Pérez, Sébastien Olive, and J. Mcleod (2026)
A new Carboniferous ‘ctenacanth’ chondrichthyan and the evolution of brain-pituitary gland communication modes
In: 18th International Symposium on Early and Lower Vertebrates (talk).
The ‘ctenacanths’ are Palaeozoic chondrichthyans known from the Upper Devonian to the Middle Permian. Their systematic status and relationships are still ambiguous, one of the reasons being the absence of clear diagnostic neurocranial characters. Here we report a new isolated 3D-preserved partial braincase from the Middle Pennsylvanian of the Excello shale from Oklahoma, USA. This study will provide putative neurocranial characters defining this group. The exceptional preservation of its pituitary region allows the reconstruction of the vascularization of the gland. The pituitary vascular system is involved in the hypothalamic-hypophysial communication and transport of hormones that regulate the major physiological functions in vertebrates. Comparisons of the vascularization of the pituitary of this fossil chondrichthyan to a new Devonian placoderm from Peru and to both embryos and juveniles from extant sharks and chimaeras provide data for future research on the evolution of the brain-hypophysis communication modes.
Abstract of an Oral Presentation or a Poster
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