Newtonsaurus, new theropod from Late Triassic of Wales (free pdf)

[Ben Creisler]

Ben Creisler

bcre...@gmail.com

Free pdf:

Newtonsaurus gen. nov. for  “Zanclodon” cambrensis Newton, 1899

Owain Evans, Cindy Howells, Nathan Wintle & Michael J. Benton (2025)
Re-assessment of a large archosaur dentary from the Late Triassic of South Wales, United Kingdom
Proceedings of the Geologists' Association 101142
doi: https://doi.org/10.1016/j.pgeola.2025.101142
https://www.sciencedirect.com/science/article/pii/S0016787825000513


A large jaw of a predatory archosaur from the latest Triassic of South Wales, named Zanclodon cambrensis, has long intrigued vertebrate palaeontologists. Could it be the oldest large theropod dinosaur? Here we reanalyse the specimen based on a new 3D digital reconstruction. We confirm first that it is indeed latest Triassic in age, most likely extracted from sandstones of the Cotham Member of the Lilstock Formation (Penarth Group, Rhaetian). Anatomically it shows features of theropod dinosaurs rather than other large non-dinosaurian predatory archosaurs of the Triassic. It shares general characteristics with European coelophysoids of similar age such as Liliensternus and Dracoraptor but is considerably larger. It is not a megalosauroid, as suggested previously, but it is unclear whether it might be an averostran or tetanuran. Its close similarity to Dilophosaurus suggests that this left-hand mandible specimen represents a more derived basal neotheropod and we assign it to a new genus, as Newtonsaurus cambrensis.

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News:

New dinosaur from Wales identified in museum drawer

https://www.bristol.ac.uk/news/2025/september/newtonsaurus-identification.html

[Maxwell Miles Candlen]

Love seeing historical material redescribed; I actually just coded this taxon in the Podokesaurus redescription analysis last week from Newton’s original figures, and it comes out in a position consistent with this paper’s conclusions.

A lot of interesting early theropod stuff coming out of Europe in the next year or so, very exciting stuff.

Maxwell Miles Candlen

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[Dawid Mazurek]

Smok cambrensis comb. nov.? 😜

[Mickey Mortimer]

The authors say "It was however named informally as a new genus ‘Newtonosaurus’ by Molnar et al. (1990)", but that is not true at all. Molnar et al. only ever call it ?Megalosaurus cambrensis and it was Welles and Pickering (1999) who proposed "Newtonsaurus" (no second 'o') for the taxon. They later get it partly right by saying "The name Newtonsaurus has been discussed in various online fora, having been established in private documents by Stephen Pickering in 1999, and has been mentioned rarely in compilations of nomenclature (e.g., Molina-Pérez and Larramendi, 2019, p. 25), but so far has been a nomen nudum, never having been proposed in a scientific paper."

Welles and Pickering, 1999. An Extract From: Archosauromorpha: Cladistics and Osteologies. 70 pp.

Mickey Mortimer 

On Thursday, September 11, 2025 at 10:11:28 AM UTC-7 Dawid Mazurek wrote:

Smok cambrensis comb. nov.? 😜

[Mickey Mortimer]

On page 5, Evans et al. write "both the caudal and distal carinae" ... umm... the caudal IS the distal, then in the figure caption below "preservation of serrations along the posterior carina". lol Consistency, who needs it? "Caudal denticle impressions are preserved on teeth 4, 5, 7, and 10 on the distal side of the mould", um can a mould have a distal side? 

"Teratosaurus suevicus, Palaeosaurus cylindrodon, Cladyodon lloydi, Avalonia sanfordi and Picrodon herveyi. All were based on isolated teeth..." Not true, Teratosaurus is based on a maxilla redescribed by your fourth author.

"Schoch (2011) re-evaluated the status of Zanclodon, assigning all the diagnostic material to the species Zanclodon laevis." All the one holotype maxilla, yes.

"Some of the taxa, such as Coelophysis, Liliensternus liliensterni, and Dracoraptor, are coelophysoids, whereas Dilophosaurus wetherilli and Sarcosaurus woodi are close to Averostra, but in the stem" and "The Welsh specimen might be said to have greatest affinity with the averostran outgroup taxon Dilophosaurus wetherilli", but then "we cannot assign the Stormy Down mandible to any existing taxon, and although we identify it as a coelophysoid, this is tentative." But you just said it was closest to a non-coelophysoid...

"... the likelihood is that the specimen belongs to an as yet unnamed species. The specific epithet cambrensis is valid...", so the species is not as yet unnamed, is it?

Oh and here they make the original mistake I mentioned again- "We therefore formally establish a new genus name, based on one earlier suggested informally (Molnar et al., 1990)." Has Evans even read The Dinosauria?

I would fault "David Martill and an anonymous reviewer", but you never know if authors heed reviewers' advice.

Mickey Mortimer

[Thomas Richard Holtz]

Yes, that puzzled me, too.

Thomas R. Holtz, Jr.
Email: tho...@umd.edu         Phone: 301-405-4084
Principal Lecturer, Vertebrate Paleontology

Office: CHEM 1225B, 8051 Regents Dr., College Park MD 20742

Dept. of Geology, University of Maryland
http://www.geol.umd.edu/~tholtz/

Phone: 301-405-6965
Fax: 301-314-9661              

Faculty Director, Science & Global Change Program, College Park Scholars

Office: Centreville 1216, 4243 Valley Dr., College Park MD 20742
http://www.geol.umd.edu/sgc
Fax: 301-314-9843

Mailing Address: 

                        Thomas R. Holtz, Jr.
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[Adam Yates]

I also note that the one proposed autapomorphy (elongated foramina within the labial sulcus), is also present in Dracovenator.

[Mickey Mortimer]

Heh. Im not surprised.  There are several taxa of dilophosaur grade with preserved dentaries that don't get mentioned in the Comparisons section- Notatessaraeraptor, Zupaysaurus, Sinosaurus (though it is mentioned twice in the description), Halticosaurus and yes, Dracovenator. Just Dilophosaurus, Liliensternus and Coelophysis bauri.

Mickey Mortimer 

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[Brad McFeeters]

Can anyone confirm the absence of "Newtonosaurus" from the 1990 first edition of The Dinosauria? I only have the 1992 paperback edition at home, which does contain minor revisions.

[mkir...@gmail.com]

"Newtonosaurus" is not listed in the Index of the 1st edition of The Dinosauria.  Newtonsaurus is not there either.  See the attached.