Should Neuquensaurus be attributed to Powell 1992?

[Mickey Mortimer]

So as part of my new series testing the validity of Titanosaurus (  The Theropod Database Blog: The Titanosaurus (in?)validity project Part 1 - Saltasaurus ), I noticed Neuquensaurus' standard authorship seems to technically be invalid.

Specifically, it's usually cited as Powell, 1992 (see attached translation), but  ICZN Article 13.3 states "To be available, every new genus-group name published after 1930 (except those proposed for collective groups or ichnotaxa) must, in addition to satisfying the provisions of Article 13.1, be accompanied by the fixation of a type species in the original publication", and Powell only ever says "Neuquensaurus australis (see Powell, 1986)", "Neuquensaurus australis (Huene, 1929)", "Neuquensaurus australis (Huene, 1929: plate 9)", "Neuquensaurus (= “Titanosaurus”) australis", AND importantly "Neuquensaurus robustus as described by Huene (1929)" and "Neuquensaurus (= "Titanosaurus" robustus, Huene 1929; plate 19: 1)". Powell makes australis the type species in his 1986 thesis, but as a thesis that's not recognized by the ICZN.

Thoughts?

Mickey Mortimer

[Tyler Greenfield]

You are right Mickey, if that translation is correct (i.e., a type species designation from the original wasn't omitted) then the authorship of Neuquensaurus cannot be attributed to Powell (1992). You will need to check other usages of the name from 1986-1999 to see if it was made available in a different publication. There would need to be a type species either explicitly designated or fixed by monotypy, and also a diagnosis or a bibliographic reference to one, though no indication of novelty (e.g., gen. nov.) is necessary. An indication of novelty is required starting in 2000 and I doubt you'll find any usages of Neuquensaurus after then which meet that requirement.

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[Adam Yates]

This is a case where even though the letter of the ICZN rules hasn't been followed there is no ambiguity at all as to what Nequensaurus was erected for, and which species should function as its type. To correct it now with a new attribution would only serve to rob Powell of authorship of his own genus name. Could some sort of case by made for the ICZN to use its plenary powers to preserve Powell 1992 as the correct attribution for Nequensaurus?

[R. Pêgas]

According to the ICZN, even after 1930, explicit designation of type species is not necessary when the new genus is monotypic. In that case there's automatic fixation my monotypy. So, is this not the case here?

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[Tyler Greenfield]

Powell (1992) included two species in Neuquensaurus, N. australis (Lydekker, 1893) and N. robustus (Huene, 1929), so it was not monotypic.

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[R. Pêgas]

Ah... I see, no, it's not. My bad.

[Iain Reid]

This topic has been briefly touched upon previously on the DML and here's what I got out of it: Powell (2003) is essentially a published version of his 1986 thesis, and does designate a type species, so it is at least the latest date it is available from, and still gives attribution to Powell (as it should). It is even possible that the name is available from Powell 1986 if that thesis qualifies as being published (which is in itself a different debate). Both Powell 1986 and Powell 1992 have been attributed as the source of the name previously (including in Powell's own 2003 publication of his thesis translated) so it really depends how strictly we want to be applying the rules that are meant to assist us. A strict application would have the name available from 2003 or 1986 depending how we judge his theses availability, but not 1992.

Whether we attribute Neuquensaurus to Powell 1986, 1992, or 2003, the name would still be credited to the proper author, and very little would change unless somehow a taxon like Rocasaurus Salgado & Azpilicueta 2000 was considered a senior synonym.

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[Tyler Greenfield]

Does Powell (2003) have an indication of novelty for Neuquensaurus? If it doesn't, then it didn't make the name available since it was published after 1999 (Article 16.1). Whether or not Powell (1986) constitutes a published work could be difficult to determine, depending on if it was ever edited for print-on-demand distribution (Article 9.12).

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[Mickey Mortimer]

The original Spanish version ( https://www.mediafire.com/file/orlx02vplw034to/Saltasaurus+loricatus+Powell+1992.pdf/file ) says "Neuquensaurus australis (véase Powell 1986)", "Neuquensaurus australis (Huene.,1929)", "Neuquensaurus australis (Huene, 1929: lám. 9)", "a la descrita por Huene (1929) para Neuquensaurus robustus", "Neuquensaurus (= "Titanosaurus") australis", "Neuquensaurus australis (Huene 1929a)", "Neuquensaurus (= "Titanosaurus") robustus Huene 1929; lám. 19: 1)", and "Neuquensaurus australls Powell 1986", so the translation seems accurate there. 

It also makes it explicit that Powell was crediting his 1986 thesis for the name- "La cara inferior del cuerpo tiene una depresión longitudinal mucho más angosta que en Neuquensaurus Powell 1986, surcada por una cresta media". So if we were to use the 1992 date, it would technically be Neuquensaurus Powell, 1986 vide Powell, 1992 or something.

Ian Reid- I don't think there's a way to claim the 1986 thesis was published then, although the 2003 volume definitely is (I'm holding a copy now), and credits Powell, 1992 for the genus. Which you noted was a problem in your DML post since it's from after 1999, so Article 16.1 kicks in ("Every new name published after 1999, including new replacement names (nomina nova), must be explicitly indicated as intentionally new").

Note Marjanovic got some things wrong in his reply to you there- that the edited 'version' of the thesis was from 2003 not 1992, and it was not monotypic.

Mickey Mortimer

[Tim Williams]

Adam Yates <yat...@gmail.com> wrote:

> This is a case where even though the letter of the ICZN rules hasn't been followed there is no ambiguity at all as to what Nequensaurus was erected for, and which species
> should function as its type. To correct it now with a new attribution would only serve to rob Powell of authorship of his own genus name.

I agree.  Prevailing usage has _Titanosaurus australis_ Lydekker, 1893 as the type species for _Neuquensaurus_ Powell, 1992.  Or maybe the date should be 2003.  Either way Powell gets attribution, so who cares?  This is one of those 'let sleeping dogs lie' things.

> Could some sort of case by made for the ICZN to use its plenary powers to preserve Powell 1992 as the correct attribution for Nequensaurus?

I doubt the ICZN needs to be bothered with this.  There is no dispute over authorship, and Powell followed the spirit of the Code.  It would be an exercise in punctilious pedantry to raise this as an issue, and take it forward as a petition.  This is the kind of thing that the Commission would probably prefer workers sort out for themselves.  

[Adam Yates]

Fair enough Tim, I agree. I only raised the idea because I was under the impression that if none of Powell's earlier uses of Nequensaurus  count as a valid establishement of a genus, then we would either have to do something silly like have someone other than Powell correctly establish the genus (or worse,  give it a new name).

[Adam Yates]

Sadly Powell (2003) does not indicate novelty for Neuquensaurus, it attributes it to Powell 1993.

[Tim Williams]

Adam Yates <yat...@gmail.com> wrote:

> Fair enough Tim, I agree. I only raised the idea because I was under the impression that if none of Powell's earlier uses of Nequensaurus  count as a valid establishement of
> a genus, then we would either have to do something silly like have someone other than Powell correctly establish the genus (or worse,  give it a new name).

Yes I take your point.  I didn't mean to give the impression that I was criticizing the basis of your idea - but I think Powell 1992 can be preserved as the correct attribution for _Neuquensaurus_ without recourse to the ICZN.

[Mickey Mortimer]

I do find it interesting to compare this to the Malkani titanosaur (and other) situations, which had an equivalent issue of him citing works not accepted by the ICZN (conference abstracts in that case, versus a thesis in Powell's) as the original authorship, so people insisted his names were invalid. Then after he did put new genus and new species in his papers, some on the DML still said 'do we have any proof the journal isn't lying about having a paper version'? But with Neuquensaurus, people are like 'eh, give it a pass', "no need to dredge that up', etc.. I would never say Malkani's work approached Powell's in its quality or accuracy, but surely the ICZN ideal is not to be a meritocracy?

Mickey Mortimer

[Milo Gaillard]

I don’t exactly know what to say about this situation, Mickey. To me, it just seems like one of those “ICZN-isms” that practically everyone forgot about and would probably rather not drudge through the effort. I know that seems kind of lazy, but it’s also just human nature.

Once again, I really do appreciate that you’re taking the time and effort to see if Titanosaurus really is invalid and dubious. It helps others see if said decision holds any water. I know you’re probably not going to publish anything about it, but I’d be cool with the OG titanosaur potential making a return.

-Milo

Sent from my iPhone

On Oct 15, 2025, at 07:05, Mickey Mortimer <therizino...@gmail.com> wrote:

I do find it interesting to compare this to the Malkani titanosaur (and other) situations, which had an equivalent issue of him citing works not accepted by the ICZN (conference abstracts in that case, versus a thesis in Powell's) as the original authorship, so people insisted his names were invalid. Then after he did put new genus and new species in his papers, some on the DML still said 'do we have any proof the journal isn't lying about having a paper version'? But with Neuquensaurus, people are like 'eh, give it a pass', "no need to dredge that up', etc.. I would never say Malkani's work approached Powell's in its quality or accuracy, but surely the ICZN ideal is not to be a meritocracy?

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[R. Pêgas]

I agree with Mickey. 

This reminds of the situation regarding Quetzalcoatlus northropi. It was originally a nomen nudum, and for a long time people treated it as available without any further discussion just for the ease of it. For moral reasons, I don't think people were wrong to keep using the name and keep attributing it to Lawson 1975. But, for the sake of following the rules, Andres petitioned the ICZN to rule it as a nomen conservadum, and the ICZN approved the petition in 2019. I do think this was the right thing to do, and perhaps the same could be done for Neuquensaurus.

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[Skye McDavid]

I should note that the ICZN has used its plenary power to rule that names that would otherwise be unavailable due to a technicality should be treated as available. Quetzalcoatlus being a fairly recent example of this. 

https://www.iczn.org/cases/all-cases/case/3728#opinion-180

I haven't checked the original references but my understanding of the situation based on this DMG thread is that Neuquensaurus is unavailable, and the appropriate course of action would be to bring a case to the ICZN asking them to confer availability and attribute authorship to Powell, 1992. 

I'm too busy to take the lead on bringing this case, but if someone has the time and wants to do this, I'd be more than happy to assist. Message me off-list. 

Skye McDavid
(she/her)

https://www.skyemcdavid.com/
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[Stephen Poropat]

A few things: 

1) A cursory search reveals that Powell used Neuquensaurus in at least one publication before 1992 (Powell, J. E. (1987). Morfologia del esqueleto axial de los dinosaurios titanosauridos (Saurischia, Sauropoda) del Estado de Minas Gerais, Brasil. In Anais do X Congresso Brasileiro de Paleontologia, pp. 155–171). No indication was made therein that it was new, but Powell did specify that he was talking about Neuquensaurus australis (Powell, 1986) at one point.

2) On page 199 of Powell (1992) he starts a section with "Neuquensaurus (=Titanosaurus sensu Huene 1929a)", and mentions both robustus and australis as species of the genus. Not much room for ambiguity there. And being before 1999/2000, novelty need not be stated, right?

3) Bonaparte (1996 [Cretaceous tetrapods of Argentina]: 106) states that "POWELL (1986) stated that the material studied by LYDEKKER and by HUENE and interpreted by them as Titanosaurus is actually a different genus, to which he named Neuquensaurus." Powell 1986 vide Bonaparte 1996? (seriously, no...)

I share Adam's stance on a petition to the ICZN; there really seems to be no practical need. As Tim suggests, this dormant canine (well, saltasaurine) should be left in repose. It could not be clearer from all of his published works what Powell considered Neuquensaurus to be, and even if his establishment of the name does not follow the ICZN to the letter, it has nonetheless been widely accepted and applied. Salgado, Otero, D'Emic, Cerda, Zurriaguz and others certainly had no trouble understanding Powell's intentions. 

If someone ever tried to sink Neuquensaurus into Rocasaurus, I imagine most sauropod workers would quietly disregard it, and continue to preferentially use Neuquensaurus. In any case, it is more likely that australis and robustus would be sunk into Saltasaurus, which is exactly what McIntosh (1990) did in the Sauropoda chapter of the first edition of The Dinosauria.

Incidentally, this line appears in McIntosh (1990: 394): "It is expected that the systematics of these animals [Titanosauridae] will improve with the publication of work by J. E. Powell (thesis, Univ. of Tucumán, 1986)." This statement is what catalysed Tom Rich to encourage Jaime Powell to properly publish his PhD (in English) in the first place. After a long wait, Tom eventually had a third party translate the thesis, and sent that translation to Jaime, stating that he would publish it. The standard of this translation was what evidently prompted Jaime to finish his own...

Justin Tweet put together a handy summary of Neuquensaurus five years ago (https://equatorialminnesota.blogspot.com/2020/01/your-friends-titanosaurs-20-neuquensaurus-normanniasaurus-notocolossus.html). The only paper published since on this animal, of which I am aware, is Zurriaguz et al. (2025), on the atlas-axis complex (https://doi.org/10.1080/08912963.2025.2486387).

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Dr Stephen F. Poropat

Deputy Director

Western Australian Organic and Isotope Geochemistry Centre

School of Earth and Planetary Sciences

Curtin University

Bentley, Western Australia

Australia 6102

https://stephenporopat.weebly.com/

[Mickey Mortimer]

That's interesting, Stephen. Powell (1987; attached translation) could be a better publication to use for Neuquensaurus. It only uses australis, so we don't have to worry about 13.3, and is before 1999 so we don't have to worry about 16.1. Powell notes two characters distinguishing it from 'series A' (MCT 1487-R; = Uberabatitan?) and one from 'series B' (MCT 1488-R and 1719-R; = Trigonosaurus types), so it technically qualifies for 13.1.1 as well ("be accompanied by a description or definition that states in words characters that are purported to differentiate the taxon").

Mickey Mortimer