In Depth
At around three meters long, Secernosaurus was very small for a hadrosaur, though its claim to fame is not size, but the fact that it was the first hadrosaur known to come from South America. In addition Secernosaurus seems to represent a saurolophine hadrosaurid similar to Kritosaurus, and saurolophines are best documented in North American and Asian fossil deposits. This caused some confusion to palaeontologists because South America was (and still is by some) believed to have been completely isolated during the late Cretaceous period.
An idea to explain the presence of hadrosaurids in South America during the end of the Cretaceous is that there might possibly have been a brief connection, or possibly some other event that allowed a brief exchange of fauna between North and South America. This is of course assuming that hadrosauroid dinosaurs did not cross in from Africa earlier on in the Cretaceous in a manner that may also explain the presence of spinosaurid dinosaurs in both Africa and South America. Unfortunately most of all we have at this time is theories based around the occurrences of fossils that do not yet show a clear transition or pattern of movement to explain the spread of hadrosaurids in South America at the end of the Cretaceous. But, now that palaeontologists know about something else that they should be looking for, it might only be a matter of time before a clearer picture can be established.
Further Reading
– Phylogeny and palaeobiogeography of hadrosaurian dinosaurs, Michael K. Brett-Surman - 1979.
