18-Scorpii-4 Fauna: Aquatic Hexapods

Among the Hexapod groups, it appears that one group suffered the greatest losses during the previous mass extinction on this planet. Only a small group of semi-aquatic animals remains, which, according to the fossil record, were the closest to what xeno-paleontologists nicknamed "the Dragons of 18Scorpii."
This group of semi-aquatic animals has been given the code name: TLD (for Testudines-Lutrinae-Dytiscidae).
These animals are recognizable by three criteria: their thicker, rigid dorsal carapace with a layer of calcified keratin (in addition to the chitin layers); their anatomy adapted for swimming but sometimes for terrestrial life, as evidenced by the first two pairs of limbs allowing them to crawl or walk on land; and their hind legs modified for swimming, taking the form of fins.
The first group was nicknamed "Turtle" because of its general appearance, which vaguely resembles sea turtles. Recognizable by their six limbs, which are actually digits, and their long neck ending in a head adapted for hunting fish, they are found mainly in warm, tropical environments, along the coast.
The second group has only been observed once during expeditions. Nicknamed "Otter," this group is distinguished by its more streamlined body, less turtle-like, with a shorter neck, limbs transformed into fins, particularly the hind legs, which are shaped like diving fins.