Last update: September 19th, 2019 at 5:00 am
A Shark at the Kasuga-2 hydrothermal system, surprised us. The Shark have diversified into over 500 species. This broader definition, the earliest known sharks date back to more than 420 million years ago
Also these sharks generally do not live in freshwater although there are a few known exceptions, such as the bull shark and the river shark, which can survive and be found in both seawater and freshwater.Therefore this shark is a group of elasmobranch fish characterized by a cartilaginous skeleton, five to seven gill slits on the sides of the head, and pectoral fins that are not fused to the head.