Bornetella sphaerica, commonly known as the spherical turtle shell, is a species of marine alga in the Dasycladaceae family.

[2] It is found in the tropical Indo-Pacific region, the type-location being Sorong, Irian Jaya, Indonesia.

The slender cylindrical stipe is continuous with the central vein that extends halfway along the thallus.

[2] Bornetella sphaerica is found in the Indo-Pacific region, its range extending from East Africa and Madagascar to Japan, the Philippines, Hawaii and northern Australia.

It grows on reefs, on rocks and dead coral heads, at depths from the low intertidal zone down to about 65 m (200 ft).