[1] Prior to 2019, J. oceanica was considered part of J. planata,[2][3] however a reexamination determined the land crabs on the oceanic islands to be a separate species.

J. oceanica differs from J. planata in the shape of the mesial lobe of the infraorbital margin and the color of its carapace.

[4] On Clipperton, the introduction of species that prey on the land crabs has had a significant impact on the island's vegetation.

The introduction of pigs on Clipperton Island by guano miners in the 1890s reduced the crab population, which allowed grassland to gradually cover about 80 percent of the atoll's land surface.

[2][6] The introduction of ship rats from shipwrecks on the island in the late 20th/early 21st century has led to a decline in the crab population, causing a corresponding increase in both vegetation and coconut palms.