The Great Barrier Reef Library

A comprehensive guide to The Great Barrier Reef

Testudines – Turtles

Green Turtle

By on February 16, 2018


Testudines, or Turtles, are an ancient family, dating back to the late Triassic period around 215 million years ago.1,2,3 There are 260 extant (living) species spread across 13 families, but only 7 of those species live in the oceans. The Great Barrier Reef is home to 6 of the 7 species of marine Turtles.

Testudines are quite unique in the Phylum of Chordata as they are the only group to have a shell. Whilst many believe that this shell is an exoskeleton, it is actually a modified rib cage. This also means that the joints of their fins are located within the rib cage, which is another unique feature.3,4,5

Turtles are generally solitary animals and can travel over 3,oookm from their feeding grounds back to the area where they were born to mate and lay their eggs. They navigate these great distances using magnetic field of the Earth. Although turtles are well equipped for life in the oceans and can hold their breath for up to seven hours, they still need to return to the surface to breathe and lay eggs.  The Common Musk Turtle (freshwater) can hibernate underwater for many months at a time holding its breath.  It does cheat a bit as it has a specialised tongue that can absorb oxygen from the water. 3,4,5,6 

Below you can find a list of the two extant families of turtles found on The great Barrier Reef.

Family – A lower level of taxonomic classification, grouping together species that show many similarities