Laboratoire de Biologie Marine, Earth and Life Institute, Université Catholique de Louvain, 1348, Louvain-la-Neuve, Belgium.
Biology of Marine Organisms and Biomimetics, Biosciences Institute, University of Mons, 7000, Mons, Belgium.
Sci Rep. 2020 Oct 30;10(1):18762. doi: 10.1038/s41598-020-75656-8.
The function of pocket shark pectoral pockets has puzzled scientists over decades. Here, we show that the pockets of the American Pocket Shark (Mollisquama mississippiensis) contain a brightly fluorescent stratified cubic epithelium enclosed in a pigmented sheath and in close contact with the basal cartilage of the pectoral fins; cells of this epithelium display a centripetal gradient in size and a centrifuge gradient in fluorescence. These results strongly support the idea that pocket shark's pockets are exocrine holocrine glands capable of discharging a bioluminescent fluid, potentially upon a given movement of the pectoral fin. Such capability has been reported in many other marine organisms and is typically used as a close-range defensive trick. In situ observations would be required to confirm this hypothesis.
几十年来，口袋鲨鱼胸鳍口袋的功能一直令科学家困惑不解。在这里，我们表明，美国口袋鲨（Mollisquama mississippiensis）的口袋内包含一个明亮荧光的分层立方上皮细胞，被色素鞘包围，并与胸鳍的基底软骨紧密接触；该上皮细胞的大小呈向心梯度，荧光呈离心梯度。这些结果强烈支持这样一种观点，即口袋鲨鱼的口袋是外分泌全分泌腺，能够排出发光液体，可能是在胸鳍的特定运动时排出。这种能力在许多其他海洋生物中都有报道，通常被用作近距离防御技巧。需要进行现场观察来证实这一假设。
