Keywords: Juvenile Tridacna costata and squamosa.jpg LargeImage en Tridacna costata Richter Roa-Quiaoit Jantzen Al-Zibdah Kochzius 2008 Juvenile shell 90 mm Old shell still grayish after cleaning The lemon yellow shell below is Tridacna squamosa Lamarck 1819 Juvenile shell 70 mm without the protruding scales Acquired around 1977 This work shows the differences between T costata and T squamosa The front and backview of T costata is in the shape of a droplet widest at the byssal orifice The front and backview of T squamosa is oval shaped and nearly has left-right symmetry T costata has five central ridges while T squamosa has four Also note that the spacing between the upright scales is smaller for T costata own MerlinCharon 2011-02-23 Cc-zero Tridacna costata Tridacna squamosa |