Enormous turtle carapace size comparison I made in the bygone era before Puentemys and Carbonemys were described. I’ll get around to remaking this at some point. These specimens — measured in Straight Carapace Length (SCL) — are, left to right:
Archelon ischyros. The gray specimen has a 1.93 meter SCL (total length 3.4 m). The black specimen is ~2.5 meters in length and inferred from reports of a specimen with a total length of 4.5 meters.
Dermochelys coriacea. The gray specimen is an average-ish specimen with a SCL of 1.5 meters. The black specimen represents either a very large specimen with a 2.1 meter carapace or the extinct leatherback Psephophorus. I need a better reference for the carapace, the point at the end seems far too large.
Drazinderetes tethyensis, an Eocene softshell turtle with a 1.25 meter bony carapace (black) which may have been 2 meters long in total (gray). There are claims the extant species Pelochelys cantorii can reach similar sizes.
And finally, a mostly complete Stupendemys with a 2.18 meter long shell (gray) and an enormous specimen with a carapace 2.18 meters wide and 3.3 meters long (black). I really really want to see that specimen.