Named By: Michael K. Brett-Surman - 1979.
Synonyms: Kritosaurus australis.
Classification: Chordata, Reptilia, Dinosauria, Ornithischia, Ornithopoda, Iguanodontia, Hadrosauroidea, Hadrosauridae, Saurolophinae.
Species: S. koerneri (type).
Size: Holotype roughly estimated to be around 3 meters long. Further remains once attributed to Kritosaurus australis suggest a much larger size beween 7.5-9 meters long
Known locations: Argentina.
Time period: Late Campanian to Early Maastrichtian of the Cretaceous.
Fossil representation: Few individuals, but usually incomplete.
around three meters long, Secernosaurus was very
small for a
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
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
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.
A species of Kritosaurus once discovered in South America and named as K. australis is now commonly classified as being further examples of Secernosaurus. This additional material suggests that Secernosaurus may have been substantially larger than the three meters indicated for the holotype. While Secernosaurus was the first genus of hadrosaurid dinosaur to be named from South America, another genus called Willinakaqe was established in 2010. Additionally this genus is considered to be similar to Secernosaurus, though is around three times the size going by currently available fossils evidence.
- Phylogeny and palaeobiogeography of hadrosaurian dinosaurs, Michael K. Brett-Surman - 1979.
- A re–evaluation of Secernosaurus koerneri and Kritosaurus australis (Dinosauria, Hadrosauridae) from the Late Cretaceous of Argentina, Alberto Prieto–Marquez and Guillermo C Salinas - 2010.