Virtual 3D modeling of the ammonoid conch to study its hydrostatic properties
Virtual 3D modeling of the ammonoid conch to study its hydrostatic properties
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DOI：
10.4202/app.00776.2020
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发表时间：
2020
影响因子：
1.8
通讯作者：
D. Morón-Alfonso;D. Peterman;Marcela Cichowolski;R. Hoffmann;R. Lemanis
中科院分区：
文献类型：
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作者：
D. Morón-Alfonso;D. Peterman;Marcela Cichowolski;R. Hoffmann;R. Lemanis
计算机断层扫描提供了丰富的生物数据，现在站在旁边的一个巨大的，更传统的，形态数据库。通过利用这两种资源，我们提出了一种新的方法来构建复杂的，虚拟的头足类动物的外壳。作为研究案例，我们使用从以前的工作中获得的数据将这种方法应用于Maorites seymourianus。为此，介绍了海螺几何形状的评价方法，并定义了新的参数，如螺段宽度膨胀率（SWER）、螺段高度膨胀率（SHER）、螺段厚度膨胀率（STER）及相关的3个指标。给出了M. Seymourianus遵循可以由多项式函数定义的螺旋。虽然类似于对数函数，但多项式拟合是优选的，因为它揭示了在早期个体发育阶段的较高的螺纹扩张值和到达成体体腔的较低的值。对虚拟模型的流体静力学特性的研究结果表明，M。seymourianus将有一个接近中性的浮力，范围从轻微的积极到轻微的消极，这取决于影响生物体质量的参数。质量中心和浮力中心的位置表明，所研究的物种将具有相对较低的流体静力学稳定性，估计壳的方向相对于垂直方向约为74-76°，孔径相对于水平平面略微向下倾斜。
Computed tomography has provided a wealth of biological data that now stands beside a vast, more traditional, morphometric database. By exploiting these two resources, we present a novel methodology to construct intricate, virtual cephalopod shells. As a case of study, we applied this method to Maorites seymourianus using data obtained from a previous work. For this purpose, evaluation of the conch geometry, and the definition of new parameters such as the segment width expansion rate (SWER), segment height expansion rate (SHER), the segment thickness expansion rate (STER), and three indices related, were introduced. The conch geometry of M. seymourianus follows a spiral that can be defined by a polynomial function. While similar to a logarithmic function, a polynomial fit is preferred because it reveals higher values of whorl expansion at the early ontogenetic phase and lower values reaching the adult body chamber. Results on the hydrostatic properties of the virtual models indicate that M. seymourianus would have a near neutral buoyancy, ranging from slightly positive to slightly negative, depending upon parameters that influence organismal mass. Positions of the center of mass and the center of buoyancy indicate that the studied species would have a relatively low hydrostatic stability, estimating a shell orientation of approximately 74–76° with respect to the vertical, with the aperture slightly inclined downwards relative to the horizontal plain.