From sea to sand – ancient marine reptiles from the deserts of Saudi Arabia
Benjamin Kear (Australia) The hot, dry deserts of modern Saudi Arabia are not renowned as a source of ancient marine reptile fossils. Indeed, only a few years ago, virtually nothing was known beyond a few unidentified scraps of bone recovered by petroleum geologists searching for oil. However, recent exploration by teams of both Saudi and international palaeontologists have led to some exciting new finds that are helping to piece together the 190 million year long story of marine reptile evolution in the Arabian Peninsula. Fig. 1. A map of the modern Arabian Peninsula (with Saudi Arabian borders) showing the extent of the Arabian Shield (lilac) and successive Mesozoic-Cainozoic sedimentary rock exposures: Late Permian to Triassic (violet); Jurassic (blue); Cretaceous (green); Cainozoic (brown). What are marine reptiles? The term ‘marine reptile’ is actually rather ambiguous and does not refer to a specific group. Rather, it applies to any wholly or partly aquatic reptile that makes, or has made, its home in the ocean. Examples of modern marine reptiles include sea turtles (chelonioids), sea snakes (related to terrestrial venomous snakes or elapids), the marine iguana (Amblyrhynchus cristatus) and the salt-water crocodile (Crocodylus porosus). The latter is typically estuarine, but commonly ventures into coastal marine areas. However, the zenith of marine reptile diversity occurred during the Mesozoic or ‘Age of Dinosaurs’, when in excess of ten major radiations, including representatives of those living today (that is, turtles, snakes, lizards and crocodiles), made the transition to life in the sea. Despite having quite different … Read More