1841

A Genuine Sea Serpent.

The Sydney Gazette and New South Wales Advertiser (NSW)
Date: February 15, 1842
Page Number: 2

The British Museum has recently received a most curious and extraordinary addition to its varieties of nature in the form of a very large sea serpent belonging to the genus Hydrus, which, with some other specimens, has been sent there by Lieutenant Stokes, of her Majesty's surveying ship Beagle. This sea snake is nearly six feet long, and about as thick as a man's thigh. It is very much larger than any specimens hitherto described, and is certainly the thickest and most weighty poisonous snake known. - London paper

Stokes did, quite literally, discover a sea-serpent: Stokes' seasnake, Astrotia stokesii.

Interestingly, the article above was reprinted two years later in colonial newspapers but without any reference to the sea-serpent being a snake.