Hydrodynamic advantages in the free-living spiriferinide brachiopod Pachycyrtella omanensis: functional insight into adaptation to high energy flow environment
Hydrodynamic advantages in the free-living spiriferinide brachiopod Pachycyrtella omanensis: functional insight into adaptation to high energy flow environment
复制标题
自由生活的spiriferinide腕足动物Pachycyrtella omanensis的水动力优势：适应高能流环境的功能洞察
作者：
Shiino;Y. and Angiolini;L.
缺乏附着或胶结机制的不活动底栖生物被认为最适合安静的海底环境。由于自由生活的下二叠纪spiriferinide臂足动物pachycyrtella omanensis生活在具有高能水流的沙质基质中，因此进行了水槽实验，以证明壳体形态在姿势稳定性和觅食流的产生方面可能具有水动力优势。建模表明，在连接面垂直于海床的垂直位置是最不稳定的，尽管这被认为是它最初的生命位置。另一方面，模型内垂直位置的被动流动表现为涡旋运动，吸入流动和呼出流动的程度不变，这有利于螺旋状滤光团对食物颗粒的有效过滤。被动进料流的强度和运动可以通过改变阀门的开启角度来调节。由于岸边的栖息地受到振荡流的影响，小型动物可能面临被埋葬的高风险，而体型的增加则更容易从沙质底部移走。为了避免这两种生理上的风险，pachycyrtella发育出了一个生长速度很高的厚壳，特别是在不改变腹侧伞形的形态功能的情况下增加了腹侧伞形的重量，以产生被动的摄食流。生物力学，功能形态，机会物种，厚环菌，Spiriferinida，悬浮饲料。
Immobile benthic organisms lacking attachment or cementation mechanisms are considered to be best adapted to quiet bottom environments. Since the free-living Lower Permian spiriferinide brachiopodPachycyrtella omanensisinhabited a sandy substrate with high-energy water flow, flume experiments were performed to show the possible hydrodynamic advantages of shell morphology in postural stability and generation of feeding flows. Modelling indicates that a vertical position, with the commissure plane perpendicular to the seabed, was the most unstable, although it is considered to have been its original life position. On the other hand, the passive flow inside the model in vertical position exhibited vortex movement with constant degree of inhalent flow and exhalent flow, conferring advantages on the effective filtration of food particles using a spiral lophophore. The intensity and movement of the passive flow for feeding could have been adjusted through changes in the angle of opening of the valves. As the shoreface habitat was affected by oscillatory flows, a small-sized animal could have undergone a high risk of burial, while an increase in size would have led to easier removal from the sandy bottom. To avoid both physical risks,Pachycyrtelladeveloped a thick shell with a high rate of growth, specifically increasing the weight of the ventral umbo without altering its morphofunction to generate passive feeding flows.Biomechanics,functional morphology,opportunistic species,Pachycyrtella,Spiriferinida,suspension feeder.