Tribulus planospira is a species of sea snail, a marine gastropod mollusk in the family Muricidae, the murex snails or rock snails. As of 2019, it is the only species in the genus
Tribulus included in the World Register of Marine Species.
Tribulus has previously been considered a subgenus of the genera
Murex,
Purpura, and
Thais.
(Wikipedia)