Dakosaurus andiniensis
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 Skull and reconstruction of Dakosaurus from National Geographic
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Extinct (fossil)
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| Dakosaurus andiniensis (Gasparini et al., 2006) |
Nicknamed Godzilla because of its short skull, Dakosaurus andiniensis was a prehistoric crocodyliform from the End Jurassic to Earliest Cretaceous of South America. The earliest fossils were discovered in 1987 in the Neuquén Basin, a very rich fossil bed in Argentina. Careful study more recently discovered cranial material has indicated that D. andiniensis is unique among the metriorhynchids (the most specialised family of crocodyliforms to marine life).
Metriorhynchids were quite common in the Jurassic and Cretaceous periods; they were small to large in size, pelagic hunters that ate mostly fish and belemnites. Most metriorhynchids, such as Geosaurus, had long, narrow snouts and jaws, which is indicative of predating upon fish and/or cephalopods. Dakosaurus andiniensis on the other hand had large, wide (> 40cm) and relatively short skull; with large, recurved and serrated teeth (more typical of dinosaurs and fossil terrestrial crocodyliforms than marine crocodyliforms). This indicates that D. andiniensis was a high-order predator. It probably predated upon other sea reptiles, including the fish-like ichthyosaurs and long necked plesiosaurs, other crocodiles and sharks. During the Jurassic period sharks were not very big, so D. andiniensis only had the gigantic species of pliosaurs as possible predators. From the 80cm long skull an estimate of just under six metres for its total length is recorded, however as crocodilians grow their entire life, there could be even larger specimens.
Dakosaurus is not an exclusive South American genus, as fossils have been found across Western Europe, but the Neuquén specimens represents a clearly distinct species.
[edit] Geological Ages
Dakosaurus andiniensis is known from the Late Tithonian of the Late Jurassic and the Earliest Berriasian of the Early Cretaceous.
[edit] References
- Gasparini, Z., Pol, D. & Spalletti, L.A. (2006). An unusual marine crocodyliform from the Jurassic-Cretaceous boundary of Patagonia. Science 311: 70-73
