Phaseolus vulgaris` Black turtle

The black turtle bean is a small, shiny variety of the common bean (Phaseolus vulgaris) especially popular in Latin American cuisine, though it can also be found in the Cajun and Creole cuisines of south Louisiana. Like all varieties of the common bean, it is native to the Americas, but has been introduced around the world. It is also used in Indian cuisine, Tamil cuisine, where it is known as karuppu kaaramani and in Maharashtrian cuisine, where it is known as Kala Ghevada. The black turtle bean is often simply called the black bean (frijoles negros, zaragoza, judía negra, poroto negro, caraota negra, or habichuela negra in Spanish; and feijão preto in Portuguese), although this terminology can cause confusion with at least three other types of black beans.

The black turtle bean is the only type of turtle bean. It is called turtle because of its hard outer "shell".

Black turtle bean - Wikipedia