Arachnosaur — Richard Jefferies

Desert Swarm
After his superior officers are killed in action, Corporal Josiah Key assumes command of the 3rd Battalion, Marine Raiders. In the tiny village of Shabhut, Yemen, while trying to put the blast on ISIS forces, an even deadlier enemy emerges: ancient, unreasoning creatures who tear into both U.S. troops and terrorists without mercy, leaving brutally dismembered corpses in their wake.

They are known as the Idmonarchne Brasieri, giant prehistoric spiders roused from millennia-long slumber by power-mad terrorists. These aptly-named 'Arachnosaurs' are hungry. They're angry. And they have declared war against all of humanity ... whose days might just be numbered unless Key and his unit can stop them.