The Atlantic Yellow Cowrie
Most species treated in this column are local. Once in a while, I introduce a shell from elsewhere that, for some remarkable reason, deserves some attention. The Atlantic Yellow Cowrie, Erosaria acicularis (Gmelin, 1791), is a relatively common Cowrie inhabiting shallow coral reef areas in the tropical western Atlantic. The species is not found, however, on the coast of Southwest Florida. As it happens with most species from the Cowrie family (Cypraeidae), the Atlantic Yellow Cowrie bears planktonic larvae (their babies drift in sea water), which will grow until the moment of metamorphosis into their adult, bottom-crawling lives. The larval shell is very distinctive from the adult one in this and most other species of Cowries. The images show two growth stages in the life of the Atlantic Yellow Cowrie. They are markedly different, representing distinctive phases in the development of the same species. In the picture on left, I show two views (in black-and-white, taken with a scanning electron microscope) of the juvenile shell and on right, the adult shell. The leftmost view shows, on top, a detail of the larval shell, which may be seen as the reticulated early shell, or protoconch.
The Atlantic Yellow Cowrie, Erosaria acicularis (Gmelin, 1791). Scale lines are, from left, 0.1 mm, 1 mm and 1 cm. Photos by José H. Leal.