The thumbnail crab, Thia scutellata, is a species of crab whose carapace resembles a human thumbnail. It is found in the North Sea, north-east Atlantic and Mediterranean Sea. It is the only extant species in the genus Thia, although two fossil species are known.
In 2002, the asteroid was detected by radar from the Arecibo Observatory at a distance of 1.31AU. The resulting data yielded an effective diameter of 125 ± 16 km.