Annulated Sea Snake (Hydrophis cyanocinctus)

The annulated sea snake, or blue-banded sea snake, is a venomous sea snake of the Indian Ocean and western Pacific, recorded from the Persian Gulf and Iran through Pakistan and India to Southeast Asia. It is greenish-olive above with blackish or olive transverse bars broadest on the back, sometimes joined by a black band along the belly (Wikipedia, general species account).

A 2019 study found that it uses a complex network of blood vessels in the head, the Modified Cephalic Vascular Network, which helps supply the brain with extra oxygen from the water when submerged (Wikipedia, general species account).