Jurassic soft-bottom oyster Crassostrea from Japan
Jurassic soft-bottom oyster Crassostrea from Japan
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DOI：
10.1111/1475-4983.00274
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发表时间：
2002-11-01
期刊：
影响因子：
2.6
通讯作者：
Matsuoka, H
中科院分区：
文献类型：
--
作者：
Komatsu, T;Chinzei, K;Matsuoka, H
描述了产于中侏罗世-白垩纪台托里群下部的牡蛎一新种--台托里近牡蛎（Crassostreatetoriensis）。这是最古老的记录属和最早的泥底牡蛎之一。该物种的特征包括一个细长的铲形轮廓和狭窄的附着区，一个细长的铰链区与深脐腔，肾形收肌疤痕，和一个光滑的连合边缘没有chomata。牡蛎彼此胶结，在推测为咸水来源的泥质沉积物中构成花束状的贝壳聚集体或群体。贝壳含有透镜状或水泡状的腔室，充满白垩存款。这些生态和结构特性是Crassostrea的特征，并且可以被视为固着、悬浮饲养动物适应软泥基质的结果。牡蛎是一组双壳类动物，它们失去了移动性，主要生活在坚硬的基底上。Crassostrea及其盟友再次回到软底。C tetoriensis的发现表明，回归发生在牡蛎历史的早期，在晚三叠世牡蛎首次出现后60万年。
A new species of oyster, Crassostrea tetoriensis, is described from the lower part of the Middle Jurassic-Cretaceous Tetori Group. This is the oldest record of the genus and one of the earliest muddy-bottom-dwelling oysters. Characteristics of the species include an elongate spatulate outline and narrow attachment area, an elongate hinge area with deep umbonal cavity, a reniform adductor muscle scar, and a smooth commissural margin without chomata. The oysters are cemented to each other and constitute bouquet-like aggregates or colonies of shells in muddy deposits of inferred brackish-water origin. The shells contain lenticular or blister-like chambers filled with a chalky deposit. These ecological and structural properties are characteristic of Crassostrea, and may be regarded as the result of adaptation of the sessile, suspension feeding animals to soft muddy substrates. Oysters are a group of bivalves that have lost mobility and live cemented mostly to hard substrates. Crassostrea and its allies returned secondarily to soft bottoms. The find of C tetoriensis indicates that the return occurred early in the history of oysters, 60 myr after the first appearance of ostreid oysters in Late Triassic.