Relationships: Crab Plover Dromas ardeola

Remarkable for its striking looks and extraordinary breeding behaviour (it nests in burrows), Crab Plover Dromas ardeola is also something of a taxonomic enigma. Its plumage would seem to relate it to avocets and stilts Recurvirostridae, while its morphology more resembles thick-knees Burhinidae.

Detailed anatomical and molecular analyses by Pereira and Baker (2010) have shown that while Crab Plover anatomy suggests that it is a sister lineage to oystercatchers Haematopodidae, genetically it is sister to pratincoles and coursers Glareolidae. On this basis, the authors also conclude that anatomical characters cannot be used with confidence to resolve shorebird relationships and that, more generally, an organism’s evolutionary history is often obscured and confused by its ecology, behaviour and physiology.