Burrow architectural types of the Atlantic ghost crab, Ocypode quadrata (Fabricius, 1787) (Brachyura: Ocypodidae), in Brazil

A broad range of aspects from paleontology to physiology of the ghost crabs Ocypode quadrata have been studied worldwide. These crabs have been used as ecological indicators of the levels of anthropogenic impacts on sandy beaches. Our aim is to report the variety of burrow architecture types constructed by ghost crabs Ocypode quadrata on beaches of Maceio, Brazil. We found 20 types of burrows that differ in shape (number of axes, number of openings, orientation of blind end, number of branches). The slash-shaped burrows (type C) were the most frequent shape, followed by types K (spiral) and E (Y-shaped). Type C also showed the largest opening diameter and length ranges. Burrow types F, J, P, S and T were the least frequent. The G-test for goodness of fit to a time-independent uniform frequency distribution (G = 417.61; d.f. = 18; p < 0.005) reject the hypothesis that burrow types are constructed randomly (uniform distribution). The dominance of type C burrows and other simple-type burrows over more elaborate types indicates preference for simplicity.