In Depth
Like with its probable relative Hupehsuchus, Nanchangosaurus looked like an ichthyosaur crossed with an archosaur. For this reason Nanchangosaurus is regarded as being analogous to an ichthyosaur though at best only distantly related to them, even though it is sometimes listed as one. Unfortunately we can only guess to this exact relationship since the kind of reptile that Nanchangosaurus truly is, is so far poorly represented in the fossil record. Additionally the immediate ancestors of the ichthyosaurs are also currently unknown, although again Nanchangosaurus does resemble primitive forms of these.
As a living reptile, Nanchangosaurus probably used its long jaws to gain additional reach in striking at prey such as fish and cephalopods. Primary swimming locomotion was probably achieved by side to side undulations of the tail, while the flipper shaped limbs steered like rudders, perhaps even helping to navigate submerged obstacles and weeds. Nanchangosaurus also had armoured ridges along its back, though these were not as well developed as those of Hupehsuchus. This might suggest that the armour was more of a throwback from a terrestrial ancestor that steadily degraded until it was eventually lost in more advanced forms, since the armour would not have been as much use in the water as it was on land. Such armour loss is seen in some later specialised marine crocodiles such as Metriorhynchus.
Further Reading
– The Enigmatic Marine Reptile Nanchangosaurus from the Lower Triassic of Hubei, China and the Phylogenetic Affinities of Hupehsuchia. – PLoS ONE 9 (7): e102361. – X. H. Chen, R. Motani, L. Cheng, D. Y. Jiang & O. Rieppel – 2014.
