Harenopterus

Harenopterus sandburgi, or more commonly known as the Giant Sandburg Sea Scorpion, was a large eurypterid (sea scorpion) that lived in the Sandburg Sea during the Lothranic period. This giant beast feasted on large fish that lived in the Sandburg Sea. Due its size, Harenopterus would have to consume a large amount of food daily, but its diet is not completely known thanks to the rarity of its fossil remains.

A singular complete fossil of this creature has been discovered directly outside of the city of Sandburg, in the Deadman's Rapids Formation. It is the most recent eurypterid known, and thought to be the last surviving member of the group.

Description
Harenopterus grew up to 7 meters long, making it one of the largest arthropods known to science. It did not possess swimming fins like earlier eurypterids; its sixth pair of appendages were atrophied into limbs used for digging. It bore ocelli atop its head, which served as a pair of simple eyes it used to watch above as the rest of the creature was buried in the sand of the seafloor.

Habitat and Ecology
Harenopterus was a benthic predator, living most of its life on the seafloor. Being unable to swim, it resorted to burying itself in the sandy seafloor to hide from both prey and predator alike.

Harenopterus is assumed to have eaten meat, as bones of unidentified creatures were found in the single fossil specimen's stomach. The main source of the meat it would have consumed is presumed to be the Horned Tiger Salmon, Palaeosalmo maximus, a large fish that is also known from the same location and time. Harenopterus would have used its large pincers to grab hold of any creature in its way, crush it until it stopped moving, then finally consuming the its prey. Because of Harenopterus ' large size, it is thought to have adopted the strategy of ambush hunting.

Extinction
Harenopterus would go extinct in the midst of the Lothranic period. It is thought that competition with, if not direct predation from, marine reptiles like the peioraids and other plesiosaurs drove them to extinction. A cooling trend over the course of the Lothranic is also suspected to have disrupted the food web and reduced the creature's habitat, as the Sandburg Sea dried significantly by the beginning of the Dracian.