For about 160 million years, dinosaurs were considered rulers of the world. They emerged during the Triassic Period (231 million years ago) and became extinct at the end of the Cretaceous Period about 66 million years ago. While the dinosaurs were the kings of the land, the seas were dominated by marine reptiles such as the paleosaurs and mosasaurs.
The Negev, during most of this period, was covered by the Tethys Sea with only the highest peak of Mt. Ramon forming an island. Therefore, dinosaurs did not roam the land and did not leave their mark in the rocks. Fortunately, 66-90 million years ago, very special conditions at the Tethys Sea created an extraordinary wealth of nutrients that led to massive algal bloom, attracting many coastal animals, such as fish, sharks and, of course, terrifying marine reptiles.
Evidence of marine reptiles in our region is not rare. The most common reptiles, and the youngest, are the mosasaurus (scientific name: Mosasuridae), some of which are considered the largest sea creatures that ever existed. The largest of them, the mosasaur, reached up to 18 meters and weighed up to 20 tons. As with the snakes, the jaw of the mosasaurs opened to the sides to allow him to swallow large prey. They had long chest fins and small hind fins and a long lizard-like tail. The mosasaurs lived in shallow waters and devoured every creature available: fish, sharks, mollusks, sea turtles, water birds and more. The remains of the mosasaurus are very common in phosphate layers (Mishash formation) in the Negev Highlands and in Mount Zin in particular. About a decade ago, the Rotem Amfert plant found a mature mosasaur skull about 1.5 meters long. Its body is estimated to have been about 17 meters long. The find is on display at the Ben-Gurion University of the Negev.
Recently, the partial skeleton of an 85 million-year-old marine reptile, an Alasmosaurid, was found in our region. The remains were found five km south of Moshav Paran in the Arava, by researchers from the Dead Sea and Arava Science Center. For the first time in Israel, many parts of a single object were found – tooth and jaw fragments, fractured limb, fins, neck and back vertebrae. The alasmosaurid, which belongs to the Plesiosauria group, was eight meters long, had a long neck, a wide, relatively flat body, a short tail and an elongated mouth full of sharp teeth. It fed on fish, ammonites and belemnites. Some believe this creature still exist in Loch Ness, Scotland, but there is no evidence.
Within Makhtesh Ramon, earlier reptilian fossils that lived along the shores of the Tethys Sea were found. Traces of frogs and salamanders in rocks from the Lower Cretaceous period (140-120 million years ago) were found in the western part of the makhtesh and are evidence of the hot and humid climate that prevailed in our region during this period. In Guy Zohalim (Reptile Valley), remains of turtle-like creatures (placodonts) that lived in coastal environments and lagoons were found, along with other ancient reptiles that lived mainly in the shallow sea and reached a length of about one meter.
Written by Dr. Sarit Ashckenazi-Polivoda and Dr. Yaron Finzi – the Dead Sea and Arava Science Center
Alasmosaur – Sea reptile in the Tethys Sea during the Upper Cretaceous:
Mosasaur: A giant sea reptile from the Upper Cretaceous Period: