Through genetics, our research group discovered a new lineage of leatherback turtle (Dermochelys coriacea) in the Mexican Pacific. Using molecular clock analysis, we estimated the divergence time of this new lineage to be 13.5 million years, which is relatively large when compared to the divergence of other sea turtles for example the divergence of the sister species of the genus Lepidochelys 4.75 Mya, or the divergence between the sister species Chelonia mydas (green turtle) and Natator depressus (flatback turtle) 7.95.

Also, at the end of the 19th century, a debate arose within the scientific community regarding the existence of two species of leatherback turtles. The first to suggest this was Garman, who proposed that Pacific leatherbacks were distinct from those in other parts of the world and therefore decided to name them Sphargis schlegelii (at that time, leatherback turtles were classified under the genus Sphargis). However, he did not provide a formal description of this new species. Later, in 1899, a Chilean scientist named Philippi described a new species of leatherback turtle, which he named S. angusta. The description of this species included a narrower shell, less visible and yellowish spots, more pointed rear flippers, and a longer neck and tail. Until the mid-1900s, two species were formally recognized, although due to a lack of evidence, it is currently considered that there is only one species.