Revisiting body size trends and nursery areas of the Neogene megatooth shark, Otodus megalodon (Lamniformes: Otodontidae), reveals Bergmann’s rule possibly enhanced its gigantism in cooler waters
Revisiting body size trends and nursery areas of the Neogene megatooth shark, Otodus megalodon (Lamniformes: Otodontidae), reveals Bergmann’s rule possibly enhanced its gigantism in cooler waters
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DOI：
10.1080/08912963.2022.2032024
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发表时间：
2022-03
影响因子：
1.4
通讯作者：
K. Shimada;Harry M. Maisch;Victor J. Perez;Martin A Becker;M. Griffiths
中科院分区：
文献类型：
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作者：
K. Shimada;Harry M. Maisch;Victor J. Perez;Martin A Becker;M. Griffiths
摘要新近纪晚期的巨齿鲨（Otodus megalodon）主要以其巨大的牙齿而闻名，其全长可能达到18-20米。我们重新研究了先前提出的身体大小的趋势和托儿所区的O。通过限制以前使用的样品，以提供更可靠的TL估计，并考虑到古纬度和海面温度的megalodon。我们证明了O.巨齿鲨在较冷的水中平均比在较暖的水中大-这一模式可归因于伯格曼规则，至少在东太平洋晚中新世和西大西洋早上新世组合中显示出纬度方向的身体大小梯度。新生儿O.虽然巨齿鲨可能利用了保育区，但先前根据体型确定的古保育区可能反映了温度依赖的趋势，而不是推断的生殖策略。因此，O.巨齿鲨在较冷的沃茨中的存活率可能因其较冷的环境而进一步提高。如果是这样的话，这项研究的推论是，不是所有的O。巨齿鲨可能同样地长到巨大的尺寸，其中通常认为该物种达到18-20米TL的概念应该主要适用于较冷环境中的种群。
ABSTRACT The late Neogene megatooth shark, Otodus megalodon, is known mainly from its gigantic teeth and possibly reached 18–20 m in total length (TL). We re-examine the previously proposed body size trends and nursery areas of O. megalodon by confining the previously used samples to upper anterior teeth offering more reliable TL estimates, and by taking paleolatitudes and sea-surface temperatures into consideration. We demonstrate that individuals of O. megalodon are on average larger in cooler water than those in warmer water – a pattern attributable to Bergmann’s rule showing a latitudinal body size gradient at least for the eastern Pacific late Miocene and the western Atlantic early Pliocene assemblages. While it is still possible that neonatal O. megalodon could have utilised nursery areas, the previously identified paleo-nursery areas based on body size may reflect temperature-dependent trends rather than the inferred reproductive strategy. Thus, the gigantism of O. megalodon in cooler waters was possibly further enhanced by its cooler environment. If so, the corollary of this study is that not all populations of O. megalodon likely grew to gigantic sizes equally, where the common notion that the species reached 18–20 m TL should be applied primarily to populations in cooler environments.