Chelonia mydas and Marine turtle

Chelonia mydas noun - Large tropical turtle with greenish flesh used for turtle soup.

Marine turtle and Chelonia mydas are semantically related. In some cases you can use "Marine turtle" instead a noun phrase "Chelonia mydas".

Marine turtle noun - Any of various large turtles with limbs modified into flippers; widely distributed in warm seas.

Chelonia mydas and marine turtle are semantically related. Sometimes you can replace phrase "Chelonia mydas" with "Marine turtle", this phrases are similar.