-18m (-10 fathoms), Scuba dived under dead coral on hard reef top, Pompano Beach, Florida, USA, 39.8mm., 2010/iv.
The « Knobby Scallop » is a colourful pecten with delicate sculpture endemic to the Caribbean region from south Florida, USA to Brazil. Often both valves carry well-developed nodules, but the knobbyness vary greatly and in some specimens they are reduced to scales or even almost completely lacking. A very well-known synonym is C. imbricata (Gmelin, 1791) which it was known under until the synonymy with Linnaeus' name became apparent. A moderately comm.on filter-feeding species, it is usually found in shallow water ranging from -5~50m deep. Typical shell length around 40mm., very rarely giants may exceed 65mm.

Oval fan-shaped, anterior auricle much larger than posterior, compressed with left valve slightly more so, solid, left valve white to yellow with squarish orange to reddish blotches, right valve lighter colored, with 8-10 major radial ribs that are knobby on left valve, scaly on right valve; interior white stained with purple and yellow. Florida, Bermuda, Bahamas, West Indies, Gulf of Mexico, Caribbean Central America, South America (Colombia, Venezuela). Length 36 mm (to 53 mm). Formerly known as Chlamys imbricata (Gmelin, 1791) (see Dijkstra, 1999).