The locally found Placid Periwinkle, Echinolittorina placida Reid, 2009, received its original scientific description and name only recently: Dr. David Reid of the Natural History Museum in London named the species in 2009, as part of his work on Tropical Periwinkles. Its shell is small (about 0.5 inch at most), pointed and solid. Found on the splash zone, on rocks or other hard substrates, in particular on seawalls, jetties, and causeway bridge pilings. The Placid Periwinkle is usually found in large numbers.
The Placid Periwinkle, Echinolittorina placida (Reid, 2009).