Taxonomical and Ecological Study on alpheid shrimps living in tunnel bored in rock at the Ryukyu Islands

在2002-2004年的研究中，在琉球群岛的Amami-Oshima岛、冲绳-Jima群岛和石垣-Jima群岛的多个地方采集了许多生活在岩石隧道中的Alpheid虾标本。对同样生活在隧道中的虾和小螃蟹进行了鉴定，并将岩石切成几片，以获取有关隧道细节的信息。隧道的形状并不总是恒定的，在较大的居民中变得更厚和更复杂，但可以肯定的是，他们不能走出隧道，因为洞口的直径(S)只有1.5-2.5毫米，远远小于虾的大小。隧道的内壁很光滑，很可能是用坚固的锤子形状的可移动手指把隧道弄得更宽更长。采集的标本经鉴定为分布于热带印度-西太平洋珊瑚礁的Alpheus obesomanus。在野外破碎岩石时，较常见的是与斜纹科Jonesius属有关的小螃蟹。显然，他们不能自己把隧道挖进岩石中，因此他们使用了被遗弃的Alpheus obesomanus隧道。对它们的详细研究表明，它们属于两个不同的属，彼此截然不同。

During this study from 2002 to 2004, many specimens of alpheid shrimps living tunnels bored in rocks were collected in many places in Amami-Oshima Island, Okinawa-jima Islands and Ishigaki-jima Islands in the Ryukyu Islands. The shrimps and the small crabs also living in tunnels were identified, and the rocks were cut into several slices to get information about details of the tunnels. Shape of the tunnels are not always constant, becoming thicker and more complicated in the larger inhabitants, but it is sure that they cannot go out of the tunnel, because the diameter of the opening(s) is (are) only 1.5-2.5 mm much smaller than the size of the shrimps. The tunnel is smooth at the inside wall, and probably made wider and longer using the strong hammer-shaped movable finger. The collected specimens were identified with Alpheus obesomanus distributed in the tropical Indo-West Pacific coral reefs.On breaking the rock in the field, small crabs referable to the genus Jonesius of the family Trapeziidae were rather commonly found. It is apparent that they cannot dig the tunnel into rock by themselves, and therefore they use the abandoned tunnel of Alpheus obesomanus. Detailed examination of them revealed that they are referred to two different genera distinct from each other.