Has this troodontid nest been described in detail?

[HD-man]

If so, what paper(s)? Link(s)? Many thanks in advance.

[Sim]

H @HD-man, I wonder if the discussion here might be of interest: http://dinotoyblog.com/forum/index.php?topic=5751.msg246266#msg246266

[HD-man]

H @HD-man, I wonder if the discussion here might be of interest: http://dinotoyblog.com/forum/index.php?topic=5751.msg246266#msg246266

@Sim Thanks! The eggs are described in that thesis, but now I have another question: Has the hatchling skeleton been described in detail? I ask b/c of this Norell quote from The World of Dinosaurs: An Illustrated Tour: "A nest of a troodontid from the Mongolian locality of Ukhaa Tolgod. It was found with hatchlings sitting on top of the nest. This may indicate that the parents continued to return to the nest after the chicks had hatched." It would make sense given what we know about Troodon (See the Horner quote), but I'd like more info if possible.

Quoting Horner ( https://www.researchgate.net/publication/268506001_Evidence_of_dinosaur_social_behavior ):

Data from Egg Mountain and Egg Island now provide extensive evidence to hypothesize the nesting behaviors of Troodon and the paleoecology of its nesting ground. The animals nested in colonies, used the nesting ground on at least three different occasions, constructed nests with rimmed borders, arranged their eggs in neat, circular clutches, brooded their eggs by direct body contact, and, apparently brought the carcasses of Orodromeus to the nesting area for their hatchlings to feed on. The hatchlings left their respective nests, but may have stayed in the nesting area for a short period of time before following the adults out of the nesting ground.

[Sim]

H @HD-man I don't know if the hatchling has been described in detail.  Is the nest Norell refers to a Byronosaurus nest?  In any case it's interesting to see the similarity in nesting behaviour between an Asian and a North American troodontid.  I agree with splitting Troodon into the Judith River Formation tooth, Stenonychosaurus and Latenivenatrix.  So I follow the suggestion by Van der Reest and Currie that the Egg Mountain troodontid is Stenonychosaurus.

[HD-man]

Is the nest Norell refers to a Byronosaurus nest?

It's the same nest, yes.

In any case it's interesting to see the similarity in nesting behaviour between an Asian and a North American troodontid.  I agree with splitting Troodon into the Judith River Formation tooth, Stenonychosaurus and Latenivenatrix.  So I follow the suggestion by Van der Reest and Currie that the Egg Mountain troodontid is Stenonychosaurus.

I agree w/splitting them up, but not necessarily w/bringing back Stenonychosaurus ("Given that [Stenonychosaurus inequalis] had already been synonymized into the senior T. formosus36 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": https://www.nature.com/articles/s41598-018-30085-6 ).

[Sim]

Keeping Stenonychosaurus a synonym of Troodon while recognising the existence of Latenivenatrix doesn't make sense.  I agree with what is said about it here:

The teeth of _T. formosus_, _S. inequalis_, and _L. mcmasterae_ cannot be distinguished from each other - this was the conclusion of a slew of recent studies. Although _S. inequalis_ has been referred to _T. formosus_ in the past (back in 1987, by Currie), this was reversed by van der Reest and Currie (2017). There is currently no evidence that the Two Medicine and Judith River material belong to a single troodontid species to the exclusion of other species (such as _L. mcmasterae_). ÂÂ

_T. formosus_ can possibly be maintained as a valid species *if* diagnostic material from the Judith River Formation is assigned to it *and* a neotype is designated. But until then, the best option is to restrict the name _T. formosus_ to the holotype. That means that _S. inequalis_ is the correct name for the diagnosable troodontid known from Lower Dinosaur Park Formation. The Two Medicine troodontid might or might not be referable to _S. inequalis_ - that remains to be determined. But referring it to to _T. formosus_ will only make troodontid taxonomy more complicated than it already is.Â

From here: http://dml.cmnh.org/2018Aug/msg00049.html

[austrosaurus]

If Troodon is non-diagnostic (as all evidence points to it being), then the name Stenonychosaurus has to come back into use regardless of personal feelings around which name you like more, as non-diagnostic species cannot have other material referred to them.