| Autor: |
Dolton HR; Discipline of Zoology, School of Natural Sciences, Trinity College Dublin, Dublin 2, Ireland., Snelling EP; Department of Anatomy and Physiology, and Centre for Veterinary Wildlife Research, Faculty of Veterinary Science, University of Pretoria, Pretoria, Gauteng 0110, South Africa., Deaville R; Institute of Zoology, Zoological Society of London, Regent's Park, London NW1 4RY, UK., Jackson AL; Discipline of Zoology, School of Natural Sciences, Trinity College Dublin, Dublin 2, Ireland., Perkins MW; Institute of Zoology, Zoological Society of London, Regent's Park, London NW1 4RY, UK., Bortoluzzi JR; Discipline of Zoology, School of Natural Sciences, Trinity College Dublin, Dublin 2, Ireland., Purves K; School of Veterinary Science, University College Dublin, Belfield, Dublin 4, Ireland., Curnick DJ; Institute of Zoology, Zoological Society of London, Regent's Park, London NW1 4RY, UK., Pimiento C; Department of Paleontology, University of Zurich, Zurich, Switzerland.; Department of Biosciences, Swansea University, Swansea, UK.; Smithsonian Tropical Research Institute, Balboa, Panama., Payne NL; Discipline of Zoology, School of Natural Sciences, Trinity College Dublin, Dublin 2, Ireland. |
| Abstrakt: |
The order Lamniformes contains charismatic species such as the white shark Carcharodon carcharias and extinct megatooth shark Otodus megalodon , and is of particular interest given their influence on marine ecosystems, and because some members exhibit regional endothermy. However, there remains significant debate surrounding the prevalence and evolutionary origin of regional endothermy in the order, and therefore the development of phenomena such as gigantism and filter-feeding in sharks generally. Here we show a basal lamniform shark, the smalltooth sand tiger shark Odontaspis ferox , has centralized skeletal red muscle and a thick compact-walled ventricle; anatomical features generally consistent with regionally endothermy. This result, together with the recent discovery of probable red muscle endothermy in filter feeding basking sharks Cetorhinus maximus , suggests that this thermophysiology is more prevalent in the Lamniformes than previously thought, which in turn has implications for understanding the evolution of regional endothermy, gigantism, and extinction risk of warm-bodied shark species both past and present. |
