Burrow morphologies of the ghost crabs Ocypode ceratophthalma and O. sinensis in foreshore, backshore, and dune subenvironments of a sandy beach in Japan

抄録

Burrow morphologies of the ghost crabs Ocypode ceratophthalma and O. sinensis were observed in foreshore, backshore, and dune subenvironments on the Irino Coast, southwestern Japan, with the aim of clarifying their paleoenvironmental significance. The observed diameter of the main shaft, burrow depth, and total burrow length varied from 14 to 40 mm, 12 to 89 cm, and 8 to 143 cm, respectively. Although the burrow diameters are largely similar among the three subenvironments, the burrows increased in length and complexity from the foreshore to dune subenvironments. These findings indicate that burrow morphology can be used as an indicator of ancient sandy beach subenvironments.