On the ``cartilaginous rider{''} in the endocasts of turtle brain cavities

Autor(es)

Werneburg, Ingmar ^{[1, 2]} ; Evers, Serjoscha W. ^[3] ; Ferreira, Gabriel ^{[1, 2]}

Afiliação do(s) autor(es)

^[1] Univ Tubingen, Senckenberg Ctr Human Evolut & Paleoenvironm, Sigwartstr 10, D-72076 Tubingen - Germany

^[2] Univ Tubingen, Fachbereich Geowissensch, HOlderlinstr 12, D-72074 Tubingen - Germany

^[3] Univ Fribourg, Dept Geosci, Chemin Musee 4, CH-1700 Fribourg - Switzerland

• Tipo de documento: Artigo Científico
• Fonte: VERTEBRATE ZOOLOGY; v. 71, p. 403-418, JUL 2 2021.
• Citações Web of Science: 0

Resumo

In recent years, paleoneurology became a very popular research field and hundreds of brain-endocasts were described. The interpretation of a dorsal protuberance of the brain-endocast puzzled researchers for a long time, the so-called (cartilaginous) rider. This is mainly because of technical limitations in the past and due to non-accessibility of comparative material. Using turtles as a case-study, we conducted a literature review and studied embryological data in addition to fossil and extant species' endocasts. We assessed three hypotheses on the origin of the rider as relating to 1) the pineal gland, to 2) the blood vessel system, and to 3) skull roof elements. Based on our integrated anatomical observations, we refute the pineal gland hypothesis (1) and an exclusive blood vessel explanation (2). However, we show that, in most cases, the cartilaginous origin applies (3). The related cartilages, mainly the anterior process of the chondrocranial tectum synoticum, can persist until adulthood. Its diversity is interpreted in regard to the mechanical support for the temporal skull region, the shape of which has been shown to be in turn related to neck retraction and jaw mechanics. Finally, we highlight the value of embryological data to provide profound hypothesesfor evolutionary research despite its low quantitative evaluability. We argue that it should be studied in conjunction with modern computer-aided data acquisition whenever possible. (AU)

• Processo FAPESP: 19/10620-2 - Macroevolução das tartarugas: contribuições de análises quantitativas, paleontologia virtual e biomecânicas
• Beneficiário: Gabriel de Souza Ferreira
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado