A case for Troodon

[Greyideas]

In 2017 a study came out claiming that Troodon is a dubious genus (not invalid like some people claim!), he goes on to state that any new fossil discoveries assigned to Troodon would need to be from the Judith river formation. He later implys that the only fossil of Judith river formation troodon is the holotype specimen (which is a tooth). The last part is actually false! I want to create a discussion around this as they have been many teeth, eggs and even vertebrae from the Judith river formation that seem to suggest that the 2017 is flawed.

 

[Troodon]

For the reason stated in Varricchio et al. paper 2018 Troodon formosus is still a valid taxon, however paleontologists may elect to use S. inequalus in campanian deposits of Canada

 

Published: 20 August 2018

An Intermediate Incubation Period and Primitive Brooding in a Theropod Dinosaur

David J. Varricchio, Martin Kundrát & Jason Hogan 

Scientific Reports volume 8, Article number: 12454 (2018) 

 

"The species Troodon formosus Leidy 185635 was originally established on a tooth from the Campanian Judith River Formation of Montana. In 1987, Currie revised the taxon and synonymized several subsequently named species into T. formosus. In 2017 van der Reest and Currie recognized that T. formosus as defined by Currie included two taxa, one of which they named Latenivenatrix mcmasterae and the other they referred to Stenonychosaurus inequalis. Given that the latter had already been synonymized into the senior T. formosus and remained unused for 30 years, Troodon formosus remains the proper name for this taxon, exclusive of L. mcmasterae, and we continue to use it here."

[Greyideas]

Just now, Troodon said:

For the reason stated in Varricchio et al. paper 2018 Troodon formosus is still a valid taxon, however paleontologists may elect to use S. inequalus in campanian deposits of Canada

 

Published: 20 August 2018

An Intermediate Incubation Period and Primitive Brooding in a Theropod Dinosaur

David J. Varricchio, Martin Kundrát & Jason Hogan 

Scientific Reports volume 8, Article number: 12454 (2018) 

 

"The species Troodon formosus Leidy 185635 was originally established on a tooth from the Campanian Judith River Formation of Montana. In 1987, Currie revised the taxon and synonymized several subsequently named species into T. formosus. In 2017 van der Reest and Currie recognized that T. formosus as defined by Currie included two taxa, one of which they named Latenivenatrix mcmasterae and the other they referred to Stenonychosaurus inequalis. Given that the latter had already been synonymized into the senior T. formosus and remained unused for 30 years, Troodon formosus remains the proper name for this taxon, exclusive of L. mcmasterae, and we continue to use it here."

I know the paper you are talking about. I have read the 2018 paper a few times actually, its one of my favorites. I was talking about Judith River specimens and how Currie neglected to mention them. Making Both the naming and fossil evidence a big problem for the 2017 paper!

[CBchiefski]

I consider Troodon to be valid. Now, it is true many of the points made by Van der Reest and Currie 2017 are also valid, and indeed there is almost no chance a genus could be erected based on a single tooth nowadays. Without question, using a tooth as the holotype is, frankly bad science. That said, we must live with the mistakes made and work to correct them. Troodon from its teeth can be linked to skeletal elements and so the name, in my mind, stands since it was first. Sadly even in recent times, a single element or a handful will be used to justify a new genus, see Thanos simonattoi, however I expect those in time to be rejected. In the literature, Choi and Lee 2019 ( see below) agreed that Troodon should remain valid but as far as I am aware, those two are the only others who have taken a stance. When I say others, I mean paleontologists who are not directly tied to Currie or Varrichio. I am tied to Varrichio and so bias of course, but as someone who has seen several Trodoon specimens, I am of the option the name is valid. As always, more specimens will greatly help in solving the debate. We need a good Troodon specimen from the Judith River, which can be named a neotype so the single tooth problem is fixed. Hopefully, that helps @Greyideas and I happy to have a discusion on Troodon.

Choi and Lee 2019: https://www.sciencedirect.com/science/article/pii/S019566711930031X

[Greyideas]

4 hours ago, CBchiefski said:

I consider Troodon to be valid. Now, it is true many of the points made by Van der Reest and Currie 2017 are also valid, and indeed there is almost no chance a genus could be erected based on a single tooth nowadays. Without question, using a tooth as the holotype is, frankly bad science. That said, we must live with the mistakes made and work to correct them. Troodon from its teeth can be linked to skeletal elements and so the name, in my mind, stands since it was first. Sadly even in recent times, a single element or a handful will be used to justify a new genus, see Thanos simonattoi, however I expect those in time to be rejected. In the literature, Choi and Lee 2019 ( see below) agreed that Troodon should remain valid but as far as I am aware, those two are the only others who have taken a stance. When I say others, I mean paleontologists who are not directly tied to Currie or Varrichio. I am tied to Varrichio and so bias of course, but as someone who has seen several Trodoon specimens, I am of the option the name is valid. As always, more specimens will greatly help in solving the debate. We need a good Troodon specimen from the Judith River, which can be named a neotype so the single tooth problem is fixed. Hopefully, that helps @Greyideas and I happy to have a discusion on Troodon.

Choi and Lee 2019: https://www.sciencedirect.com/science/article/pii/S019566711930031X

Agree, to top that, there are more speciemns of troodon from the Judith river formation, vertebrae and eggs as well as more teeth