Morphological Requirements in Limulid and Decapod Gills: A Case Study in Deducing the Function of Lamellipedian Exopod Lamellae
Morphological Requirements in Limulid and Decapod Gills: A Case Study in Deducing the Function of Lamellipedian Exopod Lamellae
复制标题
DOI：
10.4202/app.2008.0208
复制
发表时间：
2008-06
期刊：
影响因子：
--
通讯作者：
Yutaro Suzuki;A. Kondo;J. Bergström
中科院分区：
文献类型：
--
作者：
Yutaro Suzuki;A. Kondo;J. Bergström
根据一种假说，灭绝的板足节肢动物的外足具有鳃的功能。为了验证这一假设，我们记录了polyphemus的生长速度，包括总鳃面、单鳃片的平均面积和鳃片的数量。将这些速率与十足甲壳类动物的相应速率进行比较，以推断多叶鳃的形态限制。生长率以相对于动物干重的异速缩放指数表示。比较表明，无论鳃形态或动物身体计划的差异如何，每个异速生长指数在被检查物种之间是相似的。叶片数量的增长明显小于呼吸总表面积的增长。在多叶鳃中，为了满足这些趋势，整体轮廓趋于圆锥形，结果是锥体底部的表面积比尖端的表面积大几个数量级。这种几何形状似乎使总呼吸面积（总片层表面积）的数值与片层总数的立方成正比。在有板足动物的外足类动物中，情况完全不同。在后者中，片层是细长的结构，以Naraoia为例，它们在生长过程中增加的数量仅为外足类片层具有节肢动物多叶鳃锥功能所需的一半。
According to one hypothesis, the exopods of extinct lamellipedian arthropods functioned as gills. To evaluate this hypothesis, the growth rates in Limulus polyphemus for total gill surface, average area per single gill lamella and number of gill lamellae are documented. The rates are compared with corresponding rates in decapod crustaceans in order to make deductions on morphological constraints in multi-foliated gills. The growth rates are given as allometric scaling exponents relative to the animal dry-body weight. The comparisons reveal that each allometric exponent is similar among examined species irrespective of differences in gill morphology or animal body plans. The numerical growth of lamellae obviously is much smaller than the growth of the total respiratory surface. To fulfill these trends in multi-foliated gills, the overall profile tends to become conical, with the result that the surface area is a couple of magnitudes larger at the base of the cone than at the tip. This geometrical shape appears to keep the numerical value of the total respiratory area (total lamellar surface) proportional to the cube of the total number of lamellae. The situation is entirely different in animals with lamellipedian exopods. In the latter, lamellae are slender structures carried in a straight row and, as exemplified by Naraoia, their increase in number during the growth is only half that required for the exopod lamellae to have functioned as an arthropod multi-foliated gill cone.