In the last two weeks I introduced the bivalves Broad-Ribbed Carditid and Three-Tooth Carditid. Today, to complete the conversation about local members of the family Carditidae, I want to “invite to the podium” the Flattened Carditid, Pteromeris perplana (Conrad, 1841). A small bivalve, reaching only about ¼-inch, this species has a very flat shell, a feature indicated in the specific name, the Latin compound word perplana, which translates into “hyper flat”. The shell is triangular, but with a “twisted” beak. Its sculpture consists of about 12–15 ribs, and the color whitish or pinkish with brown chevron-like markings. The interior of the shell valves is almost always brown.
![The Flattened Carditid, Pteromeris perplana, from Sanibel. Photo by José H. Leal.](https://static.wixstatic.com/media/7f077a_c95070a051cb4ff8b01bc6acddcc96a2~mv2_d_3000_2712_s_4_2.jpg/v1/fill/w_147,h_133,al_c,q_80,usm_0.66_1.00_0.01,blur_2,enc_auto/7f077a_c95070a051cb4ff8b01bc6acddcc96a2~mv2_d_3000_2712_s_4_2.jpg)
The Flattened Carditid, Pteromeris perplana, from Sanibel. Photo by José H. Leal.