Dinosaur & Croc Faunal List of the Hell Creek and Lance Formations

[Troodon]

Edited (04/14/23)

 

With all of the new discoveries over the past few years there is very little out there that is current or accurate.   Here is my view of the Dinosaurian/Crocodilian fauna from the Hell Creek and Lance Formation excluding Avialae.

 

Let me add that the lack of a large dataset or complete specimens leaves many unanswered questions for many of these genera.   New discoveries will be needed to firm up a any listing of the fanual listing

 

 

Tyrannosauridae:

   - Tyrannosaurus rex (Osborn 1905)

   - Nanotyrannus lancensis (Bakker et al. 1988)

   - Aublysodon mirandus (Not Valid)

 

Alverezauridae:

 - Trierarhunchus prairiensis (Fowler et al. 2020)

 

Ornithomimidae:

- Struthiomimus sedens? (Marsh 1982)

- Ornithomimus velox (March 1890)

 

Caenagnathids:

- Anzu wyliei (Lamanna et al. 2014)

- Caenagathid indet.  including Leptorhynchos

(Discussion with P. Larsen multiple additional species probably exist and fragmentary material is known)

 

Dromaeosauridae:

- Acheroraptor temertyorum (Evans et al. 2013)

- Dakotaraptor steini (DePalma et al. 2015)

- Dromaeosaurid indet. (Discussion with P. Larsen and the fact that numerous isolated teeth & foot claws exist which do not fit the other two taxons)

- Microraptoria indet. ? (Based on isolated bones in my collection ID as possible by prominent paleontologist,  also known from North American Campanian deposits)

 

 

Troodontidae:

- Pectinodon bakkeri (Carpenter 1982)

- cf Troodon formosus

- cf Zapsalis abradens (not valid)

 

Other Theropods:

- cf Richardoestesia gilmorei

- cf Richardoestesia isosceles 

- cf Paronychodon lacustri 

 

Ankylosauria:

- Ankylosaurus magniventris (Brown 1908)

- Denversaurus schlessman (Bakker 1988)

- cf Gilyptodontopelta (Nodosaur)(Partial skeleton exists and in the process of being studied by a major museum) (have an isolated osteoderm in my collection, its very distinctive)

 

Pachycephalosauria:

- Pachycephalosaurus wyomingensis (Gilmore 1931)

- Sphaerotholus buchholtzae (Williamson et al. 2002)

- Platytholus clemensi (Horner et al. 2023)

 

Ceratopsidae:

- Leptoceratops gracilis (Brown 1914)

- Leptoceratops sp.  (BHI fragmantry material)

- Tatankaceratops sacrisonorum (Ott & Larsen 2010)

- Torosaurus latus (Marsh 1891)

- Triceratops horridus (Marsh 1889)

- Triceratops prorsus (Marsh 1890)

Others more problematic:

- Triceratops sp 2 (Fowler 2017) (MOR 3027 Yoshi specimen)

- ?Chasmosaurine MOR 1122 7-22-00-1

- ?Ceratopsian indet. (skulls floating around that are claimed to be a new species including:  Nedoceratops hatcher,  Lance Fm and Duranteceratops, Hell Creek Fm)

 

Hadrosauridae:

- Edmontosaurus annectens (Lambe 1917)

- ?Lambeosaurine (Based on a large humerus)

 

Thescelosauridae:

- Thescelosaurus neglectus (Glmore 1913)

- ?Thescelosaurus gabanii (Morris 1976) (Based on fragmentary material)

(A poster was presented at the SVP 2022 meeting of two T. neglectus skulls identified as Male and Female...T gabanii?)

 

Crocodylia:

- Borealosuchus sternbergii (Brochu 1997)

- Brachychampsa montana (Gimore 1911)

- Thoracosaurus neocesariensis (de Kay 1842)

- ? Prodiplocynodon langi (Mook 1941)

[DD1991]

Given that Pectinodon has been revalidated in recent publications, and records of Troodon from the Hell Creek Formation almost certainly might be the same taxon as Pectinodon bakkeri, the taxon "cf Troodon formosus" should be crossed out. As a matter of fact, the description of Albertavenator further demonstrates that the synonymy of Pectinodon with Troodon by Phil Currie in a 1987 publication establishing Troodon as being a senior synonym of Stenonychosaurus was untenable and future study may find the polar troodontid from the Prince Creek Formation of Alaska to be either referrable to Albertavenator or constitute a distinct species.

 

Also, Struthiomimus sedens should be changed to Ornithomimus sedens because Farlow (2001) referred Ornithomimus sedens to Struthiomimus without justification and Longrich (2008) stated that a re-appraisal of the Ornithomimus sedens holotype (USNM 4736) is needed to determine whether O. sedens is a distinct taxon and if BHI 1266 is conspecific with USNM 4736 or a distinct taxon. Indeed, BHI 1266 is yet to be described in detail, and the supplementary info for the paper by Nottrodt (2022) lists the referral of BHI 1266 to sedens as questionable. A re-appraisal of ornithomimid specimen LACM 47520 from the Hell Creek Formation might also shed light on the taxonomic affinities of O. sedens and BHI 1266 because it overlaps with the type specimens of Ornithomimus velox and O. sedens as well as BHI 1266.

 

Farlow, J.O., 2001. Acrocanthosaurus and the maker of Comanchean large-theropod footprints. pp. 408-427. In: Tanke, Carpenter, Skrepnick and Currie (eds). Mesozoic Vertebrate Life: New Research Inspired by the Paleontology of Philip J. Currie. Bloomington, IN: Indiana University Press. 

 

Longrich, N. R., 2008. A new, large ornithomimid from the Cretaceous Dinosaur Park Formation of Alberta, Canada: implications for the study of dissociated dinosaur remains. Palaeontology 51:983–997. 

 

Nottrodt, R.E., 2022. First articulated ornithomimid specimens from the upper Maastrichtian Scollard Formation of Alberta, Canada, Journal of Vertebrate Paleontology  41:5, DOI: 10.1080/02724634.2021.2019754

[Troodon]

16 hours ago, DD1991 said:

Given that Pectinodon has been revalidated in recent publications, and records of Troodon from the Hell Creek Formation almost certainly might be the same taxon as Pectinodon bakkeri,

 

Well I've done a lot of collecting in the Hell Creek and find teeth whose morphology  is identical to those described as Troodon formosus from the Judith River Formation. I also find a morphology identical to those assigned to Pectinodon teeth.  They are very very distinct and most certainly from two different taxons.  Those who claim they are the same should do their homework.

 

I'll quote David J.Varricchio et al 2018 Paper as far as what name it's called:

"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 defned 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."

So my bottom line is to remain with that name until its formally described in the Hell Creek and Lance Formation.  I also believe it's still a valid name in the JR Formation

 

16 hours ago, DD1991 said:

A re-appraisal of ornithomimid specimen LACM 47520 from the Hell Creek Formation might also shed light on the taxonomic affinities of O. sedens and BHI 1266 because it overlaps with the type specimens of Ornithomimus velox and O. sedens as well as BHI 1266.

Agree it needs re-apprasial but will continue to use S. sedens as long as publications like Longrich use it but will add a ? like Nottrodt 2022 did in his paper.

 

Longrich 2008 quote " This new ornithomimid is larger than any ornithomimid previously known from Judithan of Nirth America, and is comparable in size to Gallimimus bullets and Struthiomimus sedens"

 

[Maniraptora]

On 11/13/2022 at 2:04 PM, Troodon said:

Dromaeosauridae:

 

- Acheroraptor temertyorum (Evans et al. 2013)

- Dakotaraptor steini (DePalma et al. 2015)

- Dromaeosaurid indet. (Discussion with P. Larsen and the fact that numerous isolated teeth & foot claws exist which do not fit the other two taxons)

- Microraptoria indet. (Based on isolated claws found, known from North American Campanian deposits)

 Do you know any more about the microraptorian material? I had no idea they were present in these deposits!

[Troodon]

2 minutes ago, Maniraptora said:

 Do you know any more about the microraptorian material? I had no idea they were present in these deposits!

No, I've showed a couple of my claws to paleontologists and they come back and indicate it might be microraptorian but nothing that I'm aware of is published.  Most Ive spoken with believe they are present.  The HC has enough of a problem describing its known Dromaeosaurids so this would be taking it to another level of difficulty.  Check out Hesperonychus from the Dinosaur Park Formation.

 

 

[DD1991]

37 minutes ago, Troodon said:

 

Well I've done a lot of collecting in the Hell Creek and find teeth whose morphology  is identical to those described as Troodon formosus from the Judith River Formation. I also find a morphology identical to those assigned to Pectinodon teeth.  They are very very distinctive and most certainly from two different taxons.  Those who claim they are the same should do their homework.

 

I'll quote David J.Varricchio et al 2018 Paper as far as what name it's called:

"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 defned 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."

So my bottom line is to remain with that name until its formally described in the Hell Creek and Lance Formation.  I also believe it's still a valid name in the JR Formation

Even if you judge some of the troodontid teeth from the Hell Creek Formation more similar to Troodon than to Pectinodon, those teeth may turn to be a new taxon of troodontid that is distinct not just from Pectinodon but also Troodon because two different dromaeosaurids occur in the Hell Creek Formation (Acheroraptor and Dakotaraptor). 

[Maniraptora]

8 minutes ago, Troodon said:

No, I've showed a couple of my claws to paleontologists and they come back and indicate it might be microraptorian but nothing that I'm aware of is published.  Most Ive spoken with believe they are present.  The HC has enough of a problem describing its known Dromaeosaurids so this would be taking it to another level of difficulty.  Check out Hesperonychus from the Dinosaur Park Formation.

Thanks for the info! The ambiguity here is enough to keep me on the edge of my seat for future research. Sounds like some fodder for paleoartistic speculation, though.

[Troodon]

5 minutes ago, DD1991 said:

Even if you judge some of the troodontid teeth from the Hell Creek Formation more similar to Troodon than to Pectinodon, those teeth may turn to be a new taxon of troodontid that is distinct not just from Pectinodon but also Troodon because two different dromaeosaurids occur in the Hell Creek Formation (Acheroraptor and Dakotaraptor). 

 

I'll leave it up to the palaeontologist's to decide what to call it, all I currently know is that they are not the same taxon. 

 

Judith River Fm

 

Hell Creek Fm..looks pretty similar to the JRF tooth

 

And the tiny teeth of Pectinodon

[Troodon]

1 hour ago, Maniraptora said:

Thanks for the info! The ambiguity here is enough to keep me on the edge of my seat for future research. Sounds like some fodder for paleoartistic speculation, though.

 

Forgot not only a claw but this femur MIGHT work.  I'm sure there are more specimens out there that collectors are unaware of.

[Maniraptora]

On 11/15/2022 at 3:27 PM, Troodon said:

 

Forgot not only a claw but a femur MIGHT work.  I'm sure there are more specimens out there that collectors are unaware of.

Extra intriguing! I suppose that provides a vague ballpark on the size of the animal.

[hadrosauridae]

Well, as long as we're throwing out taxons, we should remove the nanotyrannus and give it back the name Gorgosaurus lancensis.  Maybe then the ivory tower types would stop trying to call it a baby rex.

[jpc]

Gorgosaurus lancensis?

[Troodon]

@hadrosauridae Ha ha, I like your thought process and it could be but we have enough controversy with its current name no reason to double down with this one. 

[Troodon]

7 hours ago, jpc said:

Gorgosaurus lancensis?

Check this out

https://treatment.plazi.org/id/03EF88363631FFF5FEC49BCA5549F9F9

 

[Prothereus]

On 11/13/2022 at 8:04 PM, Troodon said:

 

Ankylosauria:

- Ankylosaurus magniventris (Brown 1908)

- Denversaurus schlessman (Bakker 1988)

- cf Gilyptodontopelta (Nodosaur)(Partial skeleton exists will be studied by museum) (have an isolated osteoderm in my collection very distinctive)

 

Pachycephalosauria:

- Pachycephalosaurus wyomingensis (Gilmore 1931)

- Sphaerotholus buchholtzae (Williamson et al. 2002)

 

Ceratopsidae:

- Leptoceratops gracilis (Brown 1914)

- Leptoceratops sp.  (BHI fragmantry material)

Very interesting, thanks for the list. Do you have some more info about the Glyptodontopelta material and the BHI leptoceratopsid? 

[Troodon]

3 minutes ago, Prothereus said:

Very interesting, thanks for the list. Do you have some more info about the Glyptodontopelta material and the BHI leptoceratopsid? 

 

No it's premature to discuss both of these.

I can say that the osteoderm in my collection and those I've seen with the new material is very distinctive and similar to those found on Glyptodontopelta.

I can say this because two ankylosaurid knowledgeable paleontologist looked at my specimen and said it closest to Glyptodontopelta but that preliminary.   The other material is still in the early stages of getting it to a museum. 

 

 

On the BHI Lepto I reported that on my Sept Dig trip and stop to the BHI.

But said the following  "The purpose of going to the BHI was to pick up the Leptoceratops maxilla's I left during my June trip.  Pete has been collecting and pulling together specimens to understand and possibly describe this ceratopsid in the Hell Creek.  The material he's collected so far appears to be from an adult and is much smaller than L. gracilis.   My maxilla's seem to fit the smaller morphotype. In addition, the BHI provided me two sets of replicas of my specimens, pretty cool.

[jpc]

Here is the actual paper on Gorgosaurus lancensis.  

https://repository.si.edu/bitstream/handle/10088/22800/SMC_106_Gilmore_1946_13_1-19.pdf

[jpc]

trooodon or anyone else... do you have a pdf copy of Bakker's oroginal desxcription of Nanotyrannus?

 

Nanotyrannus, a new genus of pygmy tyrannosaur, from the Latest Cretaceous of Montana

Bakker, Robert T ; Williams, Michael

In: Hunteria, 1988, vol. 1, no. 5, p. 1

 

edit:

 

I Found it!

https://doc.rero.ch/record/14603/files/PAL_E2288.pdf

 

Edited November 16, 2022 by jpc

[Prothereus]

4 hours ago, Troodon said:

 

No it's premature to discuss both of these.

I can say that the osteoderm in my collection and those I've seen with the new material is very distinctive and similar to those found on Glyptodontopelta.

I can say this because two ankylosaurid knowledgeable paleontologist looked at my specimen and said it closest to Glyptodontopelta but that preliminary.   The other material is still in the early stages of getting it to a museum. 

 

 

On the BHI Lepto I reported that on my Sept Dig trip and stop to the BHI.

But said the following  "The purpose of going to the BHI was to pick up the Leptoceratops maxilla's I left during my June trip.  Pete has been collecting and pulling together specimens to understand and possibly describe this ceratopsid in the Hell Creek.  The material he's collected so far appears to be from an adult and is much smaller than L. gracilis.   My maxilla's seem to fit the smaller morphotype. In addition, the BHI provided me two sets of replicas of my specimens, pretty cool.

Thanks for the reply. I recall Longrich, together with Larson, presented at the Eavp some years ago a study with evidence of multiple new small dinosaurs from Hell Creek, although the results have never been  published. 

[Troodon]

39 minutes ago, Prothereus said:

Thanks for the reply. I recall Longrich, together with Larson, presented at the Eavp some years ago a study with evidence of multiple new small dinosaurs from Hell Creek, although the results have never been  published. 

 

I'm sure they are present.  Just a few years ago I got to see a very small Caenagnathidae skeleton must have been 25 cm around.  I believe it was sold to a museum in Ontario, but I have not seen anything published on it.   The digger used lots of glue and was going to be a bear to prep.    I have a pair of associate hand claws around 20 mm that might fit that specimen.  Lots of mysteries still to be uncovered in this fauna.

 

[Jurassicbro238]

Is Prodiplocynodon still considered valid? It was described from the Lance Formation and I think its known from only a single skull. This is the description paper for it.

1325804508_ProdiplocynodonDescription.pdf

[Troodon]

46 minutes ago, Jurassicbro238 said:

Is Prodiplocynodon still considered valid? It was described from the Lance Formation and I think its known from only a single skull. This is the description paper for it.

1325804508_ProdiplocynodonDescription.pdf 3.09 MB · 0 downloads

 

No idea, not heard of it before.  @jpc know anything about this guy, thought the crocs were similar to HC.?

[jpc]

I do not know the answer to this question.  One would need to look at Chris Brochu's work on Cret crocodilians... try google scholar.  I would do it myself, but I have a garageful of fossils awaiting my attention.   : ) 

[Troodon]

That's what I'm doing now

[jpc]

let me know if you need the JVP papers.  I do have access to those.