Lambeosaurus Protrachodon

Protrachodon, or how I spent hours chasing a ghost because I couldn't let it go

What the heck is a Protrachodon (and should it even be italicized)?

 (If you are thinking about being a paleontologist, this blog captures the steps I took to track down information)

You'd think it'd be easy in this digital day and age to find information on any dinosaur, especially one with a name tied to the iconic Trachodon, *the* duck-billed dinosaur when I grew up. Nothing is easy as it turns out.  As a paleontologist, I often scour old tomes, often in languages I don't understand. If you read my forays with Yangchuanosaurus and Szechuanosaurus, I was looking at Chinese papers mostly from the 1980s and 1990s.  Despite their recent age, I struggled at times to find the appropriate reference and translate it.  This time around, I had to go into the late 1800s and early 1900s literature, again in languages I couldn't read, to attempt to untie the odd knot that is... "Protrachodon,", meaning "before Trachodon."


I stumbled across "Protrachodon" while compiling a list of dinosaurs that turn 100 in 2023.  An article on Wikipedia entitled "1923 in Paleontology" lists dinosaurs named in 1923, citing its source as, the late, great George Olshevsky's website.  Alas, the link no longer works, so I couldn't check the source material.  I always prefer to work from original documentation, and no one was better than George at providing chapter and verse of paleo history.


I scrolled through the 1923 Wikipedia list and noticed a dinosaur I hadn't heard of before, "Protrachodon." By being in quotes instead of italics, the article considered it a nomen nudum, literally "naked name," which means "Protrachodon" wasn't a 'legit' dinosaur as it hadn't been published properly.  The article indicated it had been named by none other than Baron Nopcsa, who supposedly coined the term in his 1923 book 'Die Familien der Reptilien.'  A book I had just so happened to have recently perused.  However, I didn't recall reading the genus in that manuscript.  So I had to dig further. 
Wikipedia Pains


The brief descriptive text in the Wikipedia article on dinosaurs from 1923 stated "Protrachodon" is a junior synonym of Orthomerus.  Clicking on the hyperlinked "Protrachodon" teleported me to Orthomerus.  No reference to "Protrachodon" exists on the Orthomerus page.  I typed Protrachodon in the "Search Wikipedia" bar and was promptly redirected again to the Orthomerus page with nary a reason as to why.  Redirects are fine as long as either the page I'm redirected to gives me info as to why I was sent there or the sending page mentions why I am being sent elsewhere.  Call me curious, but I simply wanted to know who decided it was a nomen nudum and why, but the info wasn't provided.  At this point, most humans would shrug and move, on but I couldn't let this one go.  I had to know how the name entered the literature, why it was being considered Orthomerus, and why it wasn't "Protrachodon" on the Orthomerus page.


Wikipedia Knowledge You Might Find Useful


Fun fact, you can see who has done what on a Wikipedia page.  You likely have never clicked on "View history" which is right next to the "Search Wikipedia" rectangle on the top right of the screen yet effectively invisible despite being in easy sight, presuming you are logged into Wikipedia that is!
Wikipedia page
Clicking that button allows you to see all of the changes done to a submission.  I was able to view the first Orthomerus version submitted on May 18th, 2006, by someone named Firsfron and peruse all subsequent article modifications, large and small.  I used the Wikiblame tool to see if "Protrachodon" had ever appeared in any versions of the Orthomerus description.


As it turns out, across 106 versions of the Orthomerus page since its 2006 origin, "Protrachodon" has never appeared on the page.  Searching all of the pages via their search tool returned the following message: "Your search term was not found at all."  This was akin to a gauntlet being dropped, one I couldn't resist picking up.  I had to crack this Protrachodon->Orthomerus redirect loop.


It took some doing, but I finally got to the Protrachodon page without being redirected. There are likely easier ways to do so, but I ended up copying the Protrachodon link and then added "&redirect=no" to the address.  Who knew my middle school self-taught C64 Basic would still provide solutions 38 years later?  did a fist-pump when I promptly landed on the following non-redirected page:
Protrachodon non redirected page
Not exactly full of Protrachodon info!  And no indication as to where the name first appeared, nor why it was being automatically redirected to Orthomerus.  A click of the "View history" button showed me that Mgiganteus1on Dec 7th, 2006, created the page, and no other versions of the page have existed.  "View history" simply shows: (Redirected page to Orthomerus). The present address (URL) is a permanent link to this version.


Mgiganteus1 didn't include a rationale as to why auto-redirect was the preferred solution.  The Orthomerus page doesn't acknowledge "Protrachodon "whatsoever.  Wikipedia is a wonderful resource for when a quick info hit is needed, but for academic research it can fall short.  Individuals with access can make decisions without justification, change other's entries, and even have the power to revert changes made by someone who has done deep digging. I enjoy Wikipedia immensely but please remember to use it as a starting point for research, not as a "be all end all" source for answers.  (Rant over :-).)


Knowing the limits of Wikipedia and preferring the primary literature, I thought I'd quickly "solve for X" by dusting off some old tomes, Ctrl-f a few 1800/1900s PDFs, and move on.  Hilarity ensues...


Checking the Past


Before physically hitting the old books, I checked the 1997 Encyclopedia of Dinosaurs, a book in which I co-authored an article.  Sure enough, Protrachodon appears as nomen nudum Nopcsa, 1923.  Notice it is italicized; this implies to me the Encyclopedia article authors thought it was a valid genus that somewhere along the way had fallen out of legitimacy.  But who named it?  And when did the name appear?


Remembering the 1990s I then thought of my beloved Dinosaur Mailing List (DML), aka the dino listserv!  For those of you who weren't around at the dawn of the internet, this was *the place* to be for paleontologists.  The newest finds, hottest rumors, and sometimes vicious repartee transpired on a strangely Twitter-like listserv.  It still exists by the way. (Props to Jura at for mirroring the archive and with instructions and how to sign up to the new one)


I found on the archive that George Olshevsky wrote the following in 1999 in response to a question from Mickey Mortimer about this taxon:
<< Protrachodon Nopsca 1923>>
This is a synonym of Orthomerus. Nopcsa made up this name to give validity to 
his earlier family-level name Protrachodontidae, which had no type genus. 
Subsequently Abel (1919) and Huene (1929) reused Nopcsa's name in various 
contexts, but spelled it Protrachodontinae and Protrachodontinidae, 
respectively. None of these names has any scientific validity; they are 
historical curiosities.


I should have probably stopped here.  It was 2 AM and I had work in but a few hours, but I was so curious about Olshevsky's sentence: "Nopcsa made up this name to give validity to his earlier family-level name Protrachodontidae, which had no type genus." When did he make up the name? Where does it first appear?  Olshevsky didn't say, so off to the Nopcsa literature it was to be...

 PDFs of Centuries-old Texts

A quick double-click on my (first) pdf of Nopcsa 1923, 'Der Familien Der Reptilien', followed by a slow OCR* in Hungarian, and then in German, (I assumed it was written in Hungarian...) allowed me to begin the next phase of the quest.  As an aside, thank you Adobe for letting us scan in native languages! 


I could now use Ctrl-f (who doesn't *love* Ctrl-f?) which is a huge time saver when searching tomes.  I rarely start by searching for the entire word I seek, instead I use part of a word, ideally one without the ability to be easily hyphenated, as OCRing ancient texts can produce partial word results that the naked eye can't see.  In this case, "Protrachodon" was sometimes hyphenated in the text, and other times broken up into "Pro" and "Trachodon" as those words are in the built-in dictionary.    


A search for "trach" was rewarded with the family Trachodontidae and the subfamilies ("U. F." in the book, also you can tell from the -inae endings) Protrachodontinae and Trachodontinae.  Additionally, trachodonartigen, a reference to the Trachodontidae, Trachodontiden, Protrachodontinen, and Batrachopus (but I digress) appeared.  Keep in mind this is the book that both the Wikipedia page and Olshevsky said would contain the genus "Protrachodon" yet there was no such genus in the book!  Time to call in the cavalry.


2 AM emails were sent out and, as I suspected, they were quickly answered.  Tracy Ford and Dr. Ray Wilhite confirmed they were unable to locate "Protrachodon" anywhere in the tome.  Tracy used an analog copy and Ray a different PDF than I was using.  To be 100% certain I asked Dipanjan Munshi  and he, too, confirmed there was no appearance in the book sources said it would be in.  More PDF searches lay ahead.

I checked that old chestnut of Kuhn 1936 where I found Protrachodontinae, consisting of Orthomerus and Syngonosaurus, but no "Protrachodon."  Huene 1929 and Abel 1919 both used, as George indicated, the term Protrachodonxxx but neither reference the genus "Protrachodon."  Surely Nopcsa truly didn't create a subfamily without basing it off of a genus?  That isn't permissible under the rules of zoological nomenclature.  As an aside, cladistics allows one to do just this, maybe Nopcsa was ahead of the curve?  

Werner (1919) mentioned that the classification of Trachodontidae into Trachodontinae and Saurolophinae is unsatisfactory. That it is more correct to place Orthomerus and Kritosaurus into the Protrachodontinae and Saurolophus, Hypacrosaurus, Corythosaurus, Trachodon, Hadrosaurus, and Claosaurus into the Trachodontinae.  He cited Nopcsa 1918 for this reason.  Naturally, off to Nopcsa 1918!

The salient part of Nopcsa 1918:


Google's translation: "In any case, recognize yourself, classification
of the Trachodontidae in Trachodontinae and Saurolophinae; it seems rather correct to put Orthomerus and Kritosaurus in a subfamily "Protrachodontidae"
and compare the Trachodontinae with the forms Saurolophus, Hypacrosaurus, Corythosaurus, Trachodon, Hadrosaurus, and Claosaurus.

The Trachodontidae differ slightly from the Protrachodontidae
and are conspicuous by the strongly elongated premaxilla. The
In the first parts of these notes, provisionally adopted the classification of the
Ornithopods should be modified according to these observations."


Was this the earliest appearance of the Protrachodontidae?  Where was the actual genus "Protrachodon"?  Nopcsa knew the rules; you can't have a family or subfamily without a genus to be the bearer of the name.  I needed to go deeper in time to see if I can find an earlier appearance.

Nopcsa 1915 lists what I believe is the first use of Protrachodontidae:
Protrachodon first appearance
Protrachodontidae defined
Olshevsky was right.  No genus was given, just a family-level name.  
Nopcsa 1918 lamented Brown's hadrosaur classification could use improvement, and none of Nopcsa's, nor contemporaries, ever list "Protrachodon."  However, they do list Orthomerus without fail.  


Nopcsa 1925 uses an italicized Protrachodontida which is an odd ending and even stranger to be in italics to me. 
When I dropped said text into a Hungarian translator, it translates (emphasis mine), "Orthomerus: The discovery of vertebrae of this genus Protrachodontida has two aspects important: boviti's (sic, the translator choked on this) knowledge of this species makes it possible to compare the specialized Ornithopod (not sure what the extra "dt" means on the original word) with the primitive Rhabdodon." 


I wondered, does adding -tida in Hungarian mean not "Protrachodontida" but rather the genus Protrachodon?  I checked Nopcsa 1915 and the big 1923 book but both papers only use traditional -idae (family) -inae (subfamily), and -iden (in one place, I don't know what that means).  Am I seeing Hungarian vs German vs Latin spelling differences on the endings?  Being a paleontologist can require some deeper knowledge of linguistics than I possess.  This area certainly merits me calling in more cavalry at some future date.  However...


Night two, deep into the small hours again, it hit me.  What if there was another Nopcsa 1923?  Not the 'Der Reptilien' that everyone thinks when "Nopcsa" and "1923" are mashed together, but a more obscure publication?  Within seconds I had my answer.  As it turns out there is an obscure Nopcsa 1923 paper that describes a new tortoise, Kallokibotion, that just so happens to review Hungarian dinosaurs!  Lo and behold, I found it!!! 


I showed Tracy but he suggested this is a reference to the family still, that it is a typo on the part of Nopcsa.


Here is my read on the Google translation of the pertinent paragraph, [] contain my thoughts:
 "Since the Trachodontidae [family of duckbills] occur throughout the whole of the North American Upper Cretaceous, and since they [members of the family of duckbills] must have been derived from an Orthomerus-like type [ie. something that looks like the genus Orthomerus], the occurrence of a Protrachodon [ie. an actual genus and not the family is how I read it] at the end of the Cretaceous Period in Europe is again an atavistic trait. [meaning the presence of Protrachodon is a throwback to a more primitive/ancestral taxon that lingered, thus "before Trachodon"].  


Tracy's response to my read, "I still think he was referring it to the family since he never referred any skeletal material to the genus and if you read the previous sentences, he is using the Protrachodontidae and not Protrachodon."
The fact Nopcsa writes "a Protrachodon" instead of "Protrachodon" does suggest he might be referring to a family after all.  Or was he slyly creating the genus on the spot, knowing he hadn't done so already?  


Where it stands now
I can see why someone would think Nopcsa 1923's tortoise paper would be where the naked name "Protrachodon" could be cited as a genus.  To my eyes the genus Protrachodon is clearly in print in the 1923 paper, albeit lacking a species or holotype material reference.  This would make Protrachodonnomen nudum Nopcsa 1923, which is how we started this entire search.  Nopcsa named a number of taxa and knew well the rules of holotypes and species.  Perhaps he forgot he hadn't done it yet in this reference? Or maybe it is in a paper I haven't seen yet? Or maybe Olshevsky was correct and it was a way of quietly introducing the genus, causing others to think it must be out there somewhere already, as a way to defend the family Protrachodontidae?  We'll likely never know.

What I do know is I spent well over 8 hours in a rabbit warren (a warren is a connected series of rabbit holes) thanks to the Wikipedia entry on Orthomerus not mentioning "Protrachodon" nor any justification by Mgiganteus1's as to the auto-forwarding to Orthomerus from "Protrachodon."  I re-searched, ie. searched again, to come to the conclusion that there never was a true Protrachodon, that it is as Olshevsky said, a historical curiosity.


Welcome to paleontology!  After so much time spent I ended up where I began. I learned much along the way:
OCR in different languages
the import of different copies of PDFs when OCRing old documents
I need to befriend a linguist
Friends are important for research
I will stick with sauropods :-)
Time to put "Protrachodon" to bed and move onto the next paleo curiosity!


*FYI, when converting such documents from German via OCR I learned a few things. 
1-my version of Adobe Acrobat refused to let me "wild card search" (aka *trachodon) to find Protrachodon. 
2-I had to OCR different scans of these old texts to properly search them, each scan provided me with some new kind of scanning insight. 
3- Old High German seems to be different than modern German. 
4- the "ae" smooshed together and the "oomlats" U with some dots over it both should have been outlawed back then, my OCR software repeatedly choked on these symbols.
5- A hyphen is an enemy of ctrl-f!  Searching for Protrachodon caused me to miss an appearance because it was written Pro-trachodon, traversing two lines of text.  Thus my use of "Tracho" when searching.  Now you know!  :-)


Many thanks to Tracy Ford, who kindly went back and forth at 2 AM on multiple nights and for the scans of obscure Nopcsa papers.  And Ray Wilhite for providing different scans to make my OCR work easier.  And to Dipanjan Munshi, who not only documented the other German author's phylogenies and independently validated my efforts but seemingly found the key 1923 tortoise paper within seconds, versus my hours of thrashing about!  
Mickey Mortimer kindly pointed out:
"...the ICZN first edition didn't even come out until 1961, so "the rules" were a lot more nebulous in Nopcsa's time. Even the 1947 International Rules of Zoological Nomenclature (DOI: 10.1111/j.1474-919X.1947.tb03908.x) only states how to make a family name from the type genus (Article 4), not our more explicit current Article (a family name must " a noun in the nominative plural formed from the stem of an available generic name" and "the generic name must be a name then used as valid in the new family-group taxon"). So a Protrachodontidae without an actual genus Protrachodon would not have been wrong, just as in your 1915 excerpt he uses the family Ornithopodidae that is not based on a genus Ornithopus."


*This* is yet another reason the paleo community is amazing!  Thank you Mickey for sharing such details (and Thomas Holtz for sharing this blog to your Twitter followers!).  It makes complete sense in hindsight, the rules had to start at a point in time, and in this case it was roughly 20 years later.  I'll leave my "Nopcsa knew better" in the text and add here that he didn't know better, there wasn't "better" to know.  I'm always learning and this is a fantastic reminder that, though I view time as a horizon when I study my beloved sauropods, I need to always keep time in mind when reading research!


Back to blog


“Trachodontiden” is German for “trachodontids”.

Andreas Johansson

Hi there. Ironically it was I who asked that question about “Protrachodon” way back in 1999, and it’s great to see this more complete treatment of its history.

One point I’d like to make is that the ICZN first edition didn’t even come out until 1961, so “the rules” were a lot more nebulous in Nopcsa’s time. Even the 1947 International Rules of Zoological Nomenclature (DOI: 10.1111/j.1474-919X.1947.tb03908.x) only states how to make a family name from the type genus (Article 4), not our more explicit current Article (a family name must “…be a noun in the nominative plural formed from the stem of an available generic name” and “the generic name must be a name then used as valid in the new family-group taxon”). So a Protrachodontidae without an actual genus Protrachodon would not have been wrong, just as in your 1915 excerpt he uses the family Ornithopodidae that is not based on a genus Ornithopus.

My second thought is that in 1923, Nopcsa was using “a Protrachodon” as in “a member of this descriptive grade”, much as in 1907 he referenced "a “Pro-Avis”" when Pro-avis was not a genus and he could have written pro-avian instead.

Mickey Mortimer

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