Say Goodbye to Kronosaurus!

[DinoToyForum]

Sorry I'm confused, so Kronosaurus is found to have been a different animal actually? Which one?

The holotype of Kronosaurus is non-diagnostic so it has become a nomen dubium (Pliosauridae indet). So, all other specimens historically referred to Kronosaurus had to be reassigned to valid/new genera.

[GojiraGuy1954]

Sorry I'm confused, so Kronosaurus is found to have been a different animal actually? Which one?

The holotype of Kronosaurus is non-diagnostic so it has become a nomen dubium (Pliosauridae indet). So, all other specimens historically referred to Kronosaurus had to be reassigned to valid/new genera.

Or they could have assigned a Neotype, which they didn't do because they wanted to name a genus rather than actually fix the problem

[DinoToyForum]

Sorry I'm confused, so Kronosaurus is found to have been a different animal actually? Which one?

The holotype of Kronosaurus is non-diagnostic so it has become a nomen dubium (Pliosauridae indet). So, all other specimens historically referred to Kronosaurus had to be reassigned to valid/new genera.

Or they could have assigned a Neotype, which they didn't do because they wanted to name a genus rather than actually fix the problem

It isn't standard practice to erect a neotype in a situation like this since the holotype specimen of Kronosaurus still exists, even if the taxon isn't valid. The ICZN is clear on this. So, the authors didn't do anything wrong. I did exactly the same when I erected Meyerasaurus for 'Thaumatosaurus' - I really wanted to keep the name Thaumatosaurus for the iconic complete specimen, but the holotype was just a scrappy vertebra, so the complete skeleton got a new name as per ICZN rules. If anyone is to blame in the Kronosaurus case it's the original palaeontologist who named Kronosaurus based on scrappy non-diagnostic material, and the other palaeontologists who referred the more complete material to it! But it was a different time.

[stargatedalek]

No one uses Nomen protectum anymore...

Kronosaurus (and frankly Troodon) should easily qualify.

[DinoToyForum]

No one uses Nomen protectum anymore...

Kronosaurus (and frankly Troodon) should easily qualify.

The criteria for 'Reversal of Precedence' (and the allocation of a nomen protectum) are given in ICZN Article 23.9. My understanding from reading that is that Kronosaurus doesn't qualify.

A petition to assign a neotype was definitely the way to go, under ICZN Article 75.5, but there was no obligation for the authors to do so, and the ICZN may have rejected such a petition anyway. Petitions to the ICZN, and the allocation of neotypes, are generally a last resort.

The ICZN is online here, by the way: https://code.iczn.org
https://code.iczn.org/?frame=1

[Fembrogon]

Would a name like "Eukronosaurus" (true kronos reptile) be a reasonable cheat for a new name, hypothetically?

[DinoToyForum]

Would a name like "Eukronosaurus" (true kronos reptile) be a reasonable cheat for a new name, hypothetically?

Yes, it would have been.

[dyno77]

i do believe iv seen this type specimen in a museum ,its 1 of the most impressive partial front jaws of any prehistoric beast iv seen,its so robust ...but i remember years back reading some blog post about kronosaurus name probably being changed eventually.
Anyway the new name is very weak and other prehistoric animals have been named based on less...
still nothing is as weird as downgrading gigantopithecus to some ridiculous size such as 5ft10,when its skull and teeth clearly are of a larger frame,and even though im no anatomy expert its clear thats way to low and estimate....

[SpartanSquat]

So this happened to Monoclonius that was transferred to Centrosaurus?
NGL I dont like the name, its pretty bad, Kronosaurus is based name, like Fembrogon said, that name would work better. Many people will name it Kronosaurus, that happened before to other dinosaurs or prehistoric creatures like Indricotherium with Paraceratherium, Brontosaurus with Apatosaurus (decades ago) or Troodon with Stenonychosaurus (or viceversa)

[GojiraGuy1954]

So this happened to Monoclonius that was transferred to Centrosaurus?
NGL I dont like the name, its pretty bad, Kronosaurus is based name, like Fembrogon said, that name would work better. Many people will name it Kronosaurus, that happened before to other dinosaurs or prehistoric creatures like Indricotherium with Paraceratherium, Brontosaurus with Apatosaurus (decades ago) or Troodon with Stenonychosaurus (or viceversa)

Brontosaurus is valid though

[SpartanSquat]

I know but I said long time ago, it was invalid years ago

[stargatedalek]

So this happened to Monoclonius that was transferred to Centrosaurus?
NGL I dont like the name, its pretty bad, Kronosaurus is based name, like Fembrogon said, that name would work better. Many people will name it Kronosaurus, that happened before to other dinosaurs or prehistoric creatures like Indricotherium with Paraceratherium, Brontosaurus with Apatosaurus (decades ago) or Troodon with Stenonychosaurus (or viceversa)

Brontosaurus is valid though

But... it's not...

"Brontosaurus" was a fake dinosaur. A chimera created from remains of multiple sauropods. The name became embedded in the pop-culture zeitgeist but Brontosaurus was not real, it was fraudulent even.

A few years ago some people named a new dinosaur "Brontosaurus". Brontosaurus didn't become valid again, a completely new animal was given the re-used name.

[SpartanSquat]

A few years ago some people named a new dinosaur "Brontosaurus". Brontosaurus didn't become valid again, a completely new animal was given the re-used name.

Its possible to reuse an old name for a new animal?

[Leyster]

So this happened to Monoclonius that was transferred to Centrosaurus?
NGL I dont like the name, its pretty bad, Kronosaurus is based name, like Fembrogon said, that name would work better. Many people will name it Kronosaurus, that happened before to other dinosaurs or prehistoric creatures like Indricotherium with Paraceratherium, Brontosaurus with Apatosaurus (decades ago) or Troodon with Stenonychosaurus (or viceversa)

Brontosaurus is valid though

But... it's not...

"Brontosaurus" was a fake dinosaur. A chimera created from remains of multiple sauropods. The name became embedded in the pop-culture zeitgeist but Brontosaurus was not real, it was fraudulent even.

A few years ago some people named a new dinosaur "Brontosaurus". Brontosaurus didn't become valid again, a completely new animal was given the re-used name.

Nope. Brontosaurus excelsus (described in 1879) was known by some years when Marsh referred to it the famous skull (discovered in 1883). And nobody ever questioned the validity of Brontosaurus excelsus as a species, it was the genus Brontosaurus which was sink into Apatosaurus and then resurrected. But the excelsus species, name the genus as you wish, never was considered "a chimera created from remains of multiple sauropods".

[VD231991]

Sorry I'm confused, so Kronosaurus is found to have been a different animal actually? Which one?

The holotype of Kronosaurus is non-diagnostic so it has become a nomen dubium (Pliosauridae indet). So, all other specimens historically referred to Kronosaurus had to be reassigned to valid/new genera.

Or they could have assigned a Neotype, which they didn't do because they wanted to name a genus rather than actually fix the problem

It isn't standard practice to erect a neotype in a situation like this since the holotype specimen of Kronosaurus still exists, even if the taxon isn't valid. The ICZN is clear on this. So, the authors didn't do anything wrong. I did exactly the same when I erected Meyerasaurus for 'Thaumatosaurus' - I really wanted to keep the name Thaumatosaurus for the iconic complete specimen, but the holotype was just a scrappy vertebra, so the complete skeleton got a new name as per ICZN rules. If anyone is to blame in the Kronosaurus case it's the original palaeontologist who named Kronosaurus based on scrappy non-diagnostic material, and the other palaeontologists who referred the more complete material to it! But it was a different time.

In case anyone's aware, the holotype and referred specimen of Eiectus longmani come from the Aptian-age Doncaster Member of the Wallumbilla Formation, which is older than the type horizon of the K. queenslandicus holotype and complete specimens referred to K. queenslandicus like QM F2446, QM F18827, and QM F10113. I discussed this matter with Daniel Madzia and he agrees with me and McHenry (2009) that QM F18827 would be the most appropriate choice of a neotype for K. queenslandicus as it was found in the same geologic unit as QM F1609. Molnar (1982, 1991) as well as Thulborn and Turner (1993) suggested that the Eiectus longmani holotype might not be the same species as QM F1609 and QM F2446 and instead represent a distinct species of Kronosaurus, but the paper coining Eiectus vindicates those suggestions because it mentions that referral of all pliosaurid material from the Aptian-Albian of Australia to Kronosaurus was solely based on size and is not tenable because the Paja Formation in Colombia is home to more than one pliosaurid taxon.

McHenry, C.R. 2009. 'Devourer of Gods'. The palaeoecology of the Cretaceous pliosaur Kronosaurus queenslandicus. PhD thesis. University of Newcastle, viii + 616 pp.

Molnar, R.E., 1982. Australian Mesozoic reptiles. pp. 170-220. In: Rich, P.V., Thompson, E.M. (Eds.). Vertebrate palaeontology of Australasia. Monash University, Clayton.

Molnar, R.E., 1991. Fossil reptiles in Australia. pp. 605-702. In: Vickers-Rich, P., Monaghan, J.M., Baird, R.F. et al., (Eds.). Vertebrate palaeontology of Australasia. Pioneer Design Studio, Monash University, Melbourne.

Thulborn, T., Turner, S., 1993. An elasmosaur bitten by a pliosaur. Modern Geology 18: 489–501.

[DinoToyForum]

Sorry I'm confused, so Kronosaurus is found to have been a different animal actually? Which one?

The holotype of Kronosaurus is non-diagnostic so it has become a nomen dubium (Pliosauridae indet). So, all other specimens historically referred to Kronosaurus had to be reassigned to valid/new genera.

Or they could have assigned a Neotype, which they didn't do because they wanted to name a genus rather than actually fix the problem

It isn't standard practice to erect a neotype in a situation like this since the holotype specimen of Kronosaurus still exists, even if the taxon isn't valid. The ICZN is clear on this. So, the authors didn't do anything wrong. I did exactly the same when I erected Meyerasaurus for 'Thaumatosaurus' - I really wanted to keep the name Thaumatosaurus for the iconic complete specimen, but the holotype was just a scrappy vertebra, so the complete skeleton got a new name as per ICZN rules. If anyone is to blame in the Kronosaurus case it's the original palaeontologist who named Kronosaurus based on scrappy non-diagnostic material, and the other palaeontologists who referred the more complete material to it! But it was a different time.

I discussed this matter with Daniel Madzia and he agrees with me and McHenry (2009) that QM F18827 would be the most appropriate choice of a neotype for K. queenslandicus as it was found in the same geologic unit as QM F1609.

The point remains that a neotype can only be allocated under very specific circumstances, i.e. when "no name-bearing type specimen is believed to be extant". In the case of Kronosaurus, a name-bearing type specimen still exists – it is and always will be the holotype. The fact that it is not diagnostic is irrelevant and doesn't justify the erection of a different specimen as a neotype.

So, if QM F18827 is diagnostic and different from Eiectus longmani, it would become the holotype of another new genus. It might well be the same animal/species as 'Kronosaurus' in actuality, but that's irrelevant.


I don't agree with the above or think it makes sense, I'm just pointing out that them's the rules. A petition to the ICZN might change matters, but it would be non-standard procedure.

[VD231991]

In a recently published checklist of Mesozoic tetrapods from Australia, Poropat et al. (2023) follows Gregory Paul's field guide to Mesozoic marine reptiles in treating Eiectus longmani as separate from Kronosaurus queenslandicus, agreeing with Colin McHenry's 2009 dissertation on Kronosaurus that the marginally diagnostic nature of the K. queenslandicus holotype QM F1609 makes QM F18827 the most suitable choice of a neotype for Kronosaurus queenlandicus because both specimens come from the Toolebuc Formation. Although the authors of this paper presumably think that Leslie Noè and Marcela Gómez-Pérez should have basically petitioned the ICZN to designate QM F18827 as the K. queenslandicus neotype due to the near-lack of diagnostic features in QM F1609 rather than rush to provisionally refer all diagnostic Kronosaurus specimens from the Toolebuc Formation to Eiectus longmani in their paper on Kronosaurus due to Kronosaurus being entrenched in the literature, they nevertheless accept the erection of Eiectus longmani for MCZ 1285 not just because it comes from an older geologic unit than the Toolebuc Formation that has yielded the holotype of Kronosaurus queenslandicus and QM F18827 but also because the reconstruction of MCZ 1285 in plaster means that disassembly of the skeletal mount incorporating MCZ 1285 may reveal previously concealed morphological features distinguishing Eiectus longmani from Kronosaurus queenslandicus. 

Poropat, S.F., Bell, P.R., Hart, L.J., Salisbury, S.W., and Kear, B.P., 2023. An annotated checklist of Australian Mesozoic tetrapods. Alcheringa 47(2): 129–205.

[Sim]

It's good to see progress on this, it's nice to know Kronosaurus is valid after all, even if only known from more fragmentary remains.

[DinoToyForum]

It's open access here: https://www.tandfonline.com/doi/full/10.1080/03115518.2023.2228367

When you said "follows Gregory Paul's field guide" I was worried, but relieved to see this paper does not cite Greg Paul. Any taxonomic 'revisions' in Paul's popular book are arbitrary, not explained or justified, and should never be cited as a legitimate source.

[VD231991]

It's open access here: https://www.tandfonline.com/doi/full/10.1080/03115518.2023.2228367

When you said "follows Gregory Paul's field guide" I was worried, but relieved to see this paper does not cite Greg Paul. Any taxonomic 'revisions' in Paul's popular book are arbitrary, not explained or justified, and should never be cited as a legitimate source.

I respectfully disagree with a handful of taxonomic opinions made by Gregory Paul in his field guide to Mesozoic marine reptiles, but I wanted to  make the point that I'm glad Paul restricts Kronosaurus while treating Eiectus as a distinct form due to its older age because he knows that Kronosaurus is well-entrenched in the literature.