In Depth
Hainosaurus is usually considered to be one of the largest known mosasaurs; however its actual size is a subject of on-going study. Early length estimates placed Hainosaurus at seventeen meters, while later study towards the end of the twentieth century revised this down to fifteen. A Hainosaurus specimen from Sweden that was described by Johan Lindgran has seen the total length of Hainosaurus fall to just over 12 meters. As is always the case an exceptionally well preserved specimen of a fully grown adult would be required to settle the size of Hainosaurus without question.
Even at a more modest twelve meters, Hainosaurus was still one of the bigger predators in the late Cretaceous seas, with only very rare larger predators like Mosasaurus being able to challenge its dominance. Hainosaurus was probably a generalist predator of other large marine organisms such as turtles, smaller mosasaurs, later plesiosaurs, as well as possibly large fish and sharks. While still growing up however it may have included other types of smaller animals such as ammonites and even birds, as indicated by fossil evidence for other mosasaurs.
As a tylosaurine mosasaur Hainosaurus is thought to have been most closely related to other mosasaurs such as Tylosaurus and Taniwhasaurus.
Further Reading
– The first record of Hainosaurus (Reptilia: Mosasauridae) from Sweden. – Journal of Paleontology: Vol. 79, No. 6, pp. 1157–1165. – Johan Lindgren – 2005. – Phylogenetic and Palaeobiogeographical Analysis of Tylosaurinae (Squamata: Mosasauroidea). – University of Alberta, Ph.D dissertation. – Paulina Jimenez-huidobro – 2016. – Reassessment and reassignment of the early Maastrichtian mosasaur Hainosaurus bernardi Dollo, 1885, to Tylosaurus Marsh, 1872. – Journal of Vertebrate Paleontology – Paulina Jimenez-huidobro & Michael W. Caldwell – 2016.
