Everybody knows Triceratops, the horned dinosaur from Late Cretaceous North America, who lived 68-66 MYA.

In 2007, Eotriceratops xerinsularis was named and described (Wikipedia). It lived in (what is now) Canada about 68 MYA. It is a little bigger than Triceratops but in many aspect very similar, e.g. they both have long horns and solid frill, and postcranial skeleton. Gregory S. Paul, in his Princton Field Guide to Dinosaurs 2016, suggested putting Eotriceratops xerinsularis in the same genus as Triceratops, renaming it to Triceratops xerinsularis. I find this suggestion appealing, but I know Paul's taxonomy is unorthodox and not mainstream (e.g. I do not agree with the thesis that Torosaurus is merely a full adult Triceratops).

So the question is: can Eotriceratops xerinsularis be put in the same genus as Triceratops and is this suggestion is plausiable enough?


Taxonomists have wide leeway over assigning higher taxa. The publication process in which Eotriceratops was described as a new genus made it a new genus. However, given a different set of reviewers, they may have rejected the new generic description, and suggested that the author put it into Triceratops. The process is somewhat arbitrary, and there are some random elements to higher taxon assignment. But it is the system we use. If somebody were to write a paper to synonomize Eotriceratops with Triceratops, and that paper were accepted, then Eotriceratops would cease to be a valid name. Its all about publication precedence. Gregory Paul may have good reason for his suggestion, but it must be published before a change is made.

  • $\begingroup$ Not sure if relevant to this exact species but a VERY good talk about how & why we have so many different potentially worng) dinosaur species: ted.com/talks/jack_horner_shape_shifting_dinosaurs $\endgroup$ – Nicolai Jul 5 '18 at 9:23
  • $\begingroup$ Can you add references? $\endgroup$ – AliceD Dec 27 '18 at 19:35

Eotriceratops was a larger species of triceratops so they both were similar in name but different in size Well eotriceratops was a larger ceratopsid but both of them had different predators for example the triceratops horridus was hunted by the T-Rex but for the eotriceratops I don't what predators it had

  • $\begingroup$ Welcome. We expect answers to be clear and complete, without personal opinions. Importantly we ask answers to be supported by citations, preferably journal papers. $\endgroup$ – AliceD Dec 27 '18 at 19:36

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