A new approach using high-resolution computed tomography to test the buoyant properties of chambered cephalopod shells
A new approach using high-resolution computed tomography to test the buoyant properties of chambered cephalopod shells
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使用高分辨率计算机断层扫描测试有室头足类动物壳的浮力特性的新方法
DOI：
10.1017/pab.2014.17
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发表时间：
2015
期刊：
影响因子：
--
通讯作者：
Hoffmann
中科院分区：
文献类型：
--
作者：
Lemanis;Zachow;Fusseis;Hoffmann
现代头足类动物的分室壳起着浮力装置的作用，使动物能够进入水柱而不需要花费大量的能量来克服自身的重量。事实上，分室壳在很大程度上被认为是一种关键的适应，使最早的头足类动物能够离开海底进入水柱。然而，一些人认为，古生代和中生代菊石的标志性腔壳并没有提供足够的浮力来补偿整个动物的重量，从而限制了菊石的生活方式，让人想起一些章鱼。在这里，我们开发了一种技术，使用高分辨率的计算机断层扫描来量化的浮力性能的分室壳，而不减少壳理想的螺旋或消除固有的生物变异性，通过使用数学模型，在这方面的特点过去的工作。这一技术已在鹦鹉螺身上试验过，现在已推广到现存的深海鱿鱼Spirula spirula和侏罗纪菊石Cadoceras sp.幼体。当壳有三到五个腔室时，如果孵化出来，卡多角石被发现具有接近中性到正浮力。然而，我们表明，动物也可以克服程度的负浮力通过游泳，类似于现代鱿鱼的pneumararcadium。这些计算挑战了过去仅根据负浮力计算得出的底栖生物习性推论。计算出的浮力的Cadoceras支持的可能性，菊石幼体的扩散。这些信息对于了解菊石生态学以及生物相互作用至关重要，并对解释从壳的同位素分析中获得的地球化学数据具有影响。
The chambered shell of modern cephalopods functions as a buoyancy apparatus, allowing the animal to enter the water column without expending a large amount of energy to overcome its own weight. Indeed, the chambered shell is largely considered a key adaptation that allowed the earliest cephalopods to leave the ocean floor and enter the water column. It has been argued by some, however, that the iconic chambered shell of Paleozoic and Mesozoic ammonoids did not provide a sufficiently buoyant force to compensate for the weight of the entire animal, thus restricting ammonoids to a largely benthic lifestyle reminiscent of some octopods. Here we develop a technique using high-resolution computed tomography to quantify the buoyant properties of chambered shells without reducing the shell to ideal spirals or eliminating inherent biological variability by using mathematical models that characterize past work in this area. This technique has been tested on Nautilus pompilius and is now extended to the extant deep-sea squid Spirula spirula and the Jurassic ammonite Cadoceras sp. hatchling. Cadoceras is found to have possessed near-neutral to positive buoyancy if hatched when the shell possessed between three and five chambers. However, we show that the animal could also overcome degrees of negative buoyancy through swimming, similar to the paralarvae of modern squids. These calculations challenge past inferences of benthic life habits based solely on calculations of negative buoyancy. The calculated buoyancy of Cadoceras supports the possibility of planktonic dispersal of ammonite hatchlings. This information is essential to understanding ammonoid ecology as well as biotic interactions and has implications for the interpretation of geochemical data gained from the isotopic analysis of the shell.
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白垩纪菊总科孵化后早期生活史
DOI：
10.1111/j.1502-3931.1993.tb01804.x
发表时间：
1993
期刊：
影响因子：
--
作者：
Y. Shigeta
通讯作者：
Y. Shigeta
螺旋藻——菊石胚胎发育的窗口？古生物学假说的形态学和分子指示
DOI：
--
发表时间：
2005
期刊：
影响因子：
--
作者：
K. Warnke;H. Keupp
通讯作者：
H. Keupp
白垩纪的蛇颈龙吃菊石
影响因子：
64.8
作者：
Tamaki Sato;K. Tanabe
通讯作者：
K. Tanabe
鹦鹉螺的自然历史
DOI：
--
发表时间：
1987
期刊：
影响因子：
--
作者：
P. Ward
通讯作者：
P. Ward
根据 Aptychi 估计的菊石生长率
DOI：
--
发表时间：
1993
期刊：
影响因子：
--
作者：
R. Hewitt;G. Westermann;A. Checa
通讯作者：
A. Checa