Making Junk of Dicynodont Trunks

Bill Munn's sculpture of a trunked Giraffatitan.
Classic imagery. Original photo featured on Cryptomundo, I think?

In the realms of the palaeo-blogosphere, one article I would consider to be essential reading is Tetrapod Zoology's Junk in the trunk: why sauropod dinosaurs did not possess trunks, which speaks for itself (and apologies to Darren for shamelessly riffing on his title).

As I'm sure some of you are familiar with, it’s become a fairly recurring pattern in vertebrate palaeontology for certain clades with peculiar nasal anatomy to be (often ultimately incorrectly) proposed to have had trunks. The idea of trunked sauropods has been decidedly debunked, dismissed and derided, but even such well established examples of purportedly trunked fossil tetrapods like Macrauchenia have recently been proposed to be stripped of their proboscises on account of incompatible musculature and other anatomical grounds.

But did you know that dicynodonts also got in on the trunk craze? Given that you're here and read the title, I'd imagine you'd already guessed that. But did you also know that they got in on the craze almost a whole century ahead of the game? Yes indeed, it may be seldom acknowledged nowadays but there really was one time when a dicynodont was proposed to have had a trunk. It wasn't just any dicynodont either, but arguably one of the more famous names in the dicynodont roster, Kannemeyeria, and in fact the original specimen from which it was named to boot.

Kannemeyeria was coined by British palaeontologist Harry Seeley (of Saurischia and Ornithischia fame) in September of 1908 at the 78th meeting of The British Association, published as a brief description just over half a page long. Seeley unfortunately died just some months later in January of 1909, and to my knowledge Kannemeyeria may be one the last taxa he ever named. However, it was not for the familiar K. simocephalus we know today. Indeed, that species had already been named twenty years earlier in 1888 by German palaeontologist Anton Weithofer, who regarded it as a species of Dicynodon (as of course was tradition for many dicynodont fossils in the 19th and early 20th century).

Seeley named Kannemeyeria from a peculiar partial skull discovered in the Karoo Basin of South Africa by fossil collector (among various other professions) Dr. Daniel Rossouw Kannemeyer in 1895, whose find would ultimately bear his name. The skull was, in Seeley's words, "not perfect" and pretty busted up and incomplete, but Seeley recognised it as a dicynodont for its toothless jaws and paired tusks (which I assume are broken, as I can't make them out much in the few images I could find of the fossil —scratch that, better photos provided by Dr. Christian Kammerer below more clearly show the tusks set in the jaw). However, one feature stood out to Seeley that compelled him to describe it as an entirely new genus and species that he named Kannemeyeria proboscoides. You can probably guess why.

Seeley's type specimen of Kannemeyeria proboscoides, viewing the left side from slightly above (a), underside (b), and the top side (c). The specimen's not very pretty, and neither are the pictures, but it's the best I could find (UPDATE: better quality photos have been provided at the bottom of the post!). From Cruickshank (1970).

Yes, Seeley was quite convinced that this was a hitherto unknown dicynodont with a trunk, and adamantly so at that. He explicitly described the area for the trunk insertion as being elephantine in structure, not like the short and stout proboscis of a tapir. Now usually in cases like these it’s at least understandable how a certain fossil's anatomy can invoke the possibility of a trunk: raised nostrils, large narial openings, abbreviated snouts, and so on. But how does the beaked skull of a dicynodont, which typically have small nostril openings I might add, even come remotely close to looking like it should have a trunk?

The simple answer is that the specimen Kannemeyer found was broken, and that the bean-shaped opening left behind by the broken-off snout was interpreted as the entire nasal aperture. In fact, most of the skull is missing, it's mostly a palate with part of the top of the snout and a left eye, the rest is all missing. In hindsight, the beak simply just being broken off sounds glaringly obvious, but let’s be kind to Seeley. The scope of dicynodont anatomy was still poorly understood at the time, and the tusk-bearing region was still roughly intact, so it's not inconceivable to have interpreted a large forward-opening hole in the skull as a natural feature. After all, by itself it's not that outrageous, especially when it recalls to mind another famously trunked synapsid with a large, vaguely bean-shaped opening on the front of its skull and a prominent pair of tusks. 

Synapsid? Check! Two tusks? Double check!
Vaguely bean-shaped narial opening? Check! Kannemeyeria proboscoides confirmed.
Photo byJimJones1971 (CC BY-SA 3.0).

The story gets even more interesting, though. Seeley went on to speculate on the lifestyle and habits of his Kannemeyeria proboscoides in surprising detail. He concluded that Kannemeyeria was something like an aardvark or giant anteater, using its tusks to rip open and tear down termite nests, a trait he ascribed to other dicynodonts as well. Quite how the trunk was involved with this is a bit of a puzzle to me, admittedly. He compares it to the elongated snouts of aardvarks and anteaters as a "soft flexible" extension of the head, but in these mammals the snout is stiff and tubular with the mouth situated at the very end, totally unlike the short jaws and trunk of elephants. Was it supposed to suck them up the way anteaters do in cartoons? Who knows.

Whatever Seeley exactly had in mind for Kannemeyeria, it didn't stick. Just four years later, David M.S. Watson recognised that Seeley's skull was an imperfect specimen of Weithofer's Dicynodon simocephalus, and while opinions on the internal taxonomy of Kannemeyeria differed in the years since, there was no question that Kannemeyeria had a beak like other dicynodonts. Seeley never illustrated his trunked dicynodont in the flesh (in fact he didn't even illustrate the fossil either), and as far as I can tell, no palaeoartists seem to have ever picked up on his suggestion either, before and after it was debunked. Which is a real shame, since this would be a fantastic subject for those goofy looking pieces of outdated palaeoart we all love to poke fun at. With that said, I’ve taken the liberty of doing it myself.

And so I present to you Seeley's trunked Kannemeyeria proboscoides in all its goofy glory:

My imagining of how Seeley may have imagined Kannemeyeria.

Now obviously this doesn't look much like Kannemeyeria at all, even ignoring the trunk, but I was trying to illustrate it through the lense of Seeley's interpretation in 1908. Admittedly, the type skull of 'D.' simocephalus was already known at the time, which preserved the characteristically crested parietal region we're so familiar with. However, Seeley made no connection between his proboscoides and 'D.' simocephalus, and there's no indication that he thought that his specimen would have been much different from most other dicynodonts in the rear of the skull. As such, I illustrated it with a more typical-looking skull (trunk notwithstanding). I kept the beak on the lower jaw, as Seeley also believed dicynodonts to be insectivores with a long, extendable tongue that slotted into a groove in their lower jaws and beaks, with the trunk of K. proboscoides presumably being a further specialisation of this lifestyle. The trunk itself is based on those of proboscideans, as Seeley described, with particular inspiration from gomphotheres and other early proboscideans given its more horizontally projecting arrangement.

Seeley’s trunked Kannemeyeria seems to have only ever made it into its brief, nominative publication before being dismissed and all but forgotten. At best, it has been relegated to a brief tidbit regarding Seeley’s misplaced taxonomy to explain the story behind the "proboscoides" name. To my knowledge, no one has ever made a similar suggestion since then either, although that's not surprising, putting a trunk on any dicynodont would be a pretty bold and brash claim to make (and would almost certainly belong in the trash). There's no controversy to be had, and it's incredibly unlikely the idea will ever be proposed again, but it's a quirky piece of history in dicynodont research and a fun idea to look back on.

Though, to be honest, if any non-mammalian synapsid was ever going to turn up one day with good evidence for a trunk of some sort, my money would be on it being an anomodont. It just sounds like it would be in their repertoire.

Addendum (16/07/21)

Update! Not long after posting, Dr. Christian Kammerer kindly provided some clear, high quality photos of Seeley's type specimen of Kannemeyera proboscoides! He also politely corrected me where I accidentally switched his name for Dr. Kannemeyer's...my bad.

Also, since the world seems to be devoid of decent pictures of this specimen: pic.twitter.com/2pdQsUJQLO

— Christian Kammerer (@Synapsida) July 16, 2021

Sources

Cruickshank, A. (1970). Taxonomy of the Triassic anomodont genus Kannemeyeria. Palaeontologia africana, 713, 47–55.

Haughton, S. H. (1915). On a Skull of the Genus Kannemeyeria. Annals of the South African Museum, 12, 91–97.

Seeley, H. (1909). On a fossil reptile with a trunk from the Upper Karroo rocks of Cape Colony. Report of the British Association for the Advancement of Science 1908, 78, 713.

Watson, D. M. S. (1912). On some reptilian low jaws. Annals and Magazine of Natural History, 10 (60), 573–587.

Weithofer, A. (1888). Ueber einen neuen Dicynodonten (Dicynodon simocephalus) aus der Karrooformation Südafrikas. Annalen des Naturhistorischen Museums in Wien, 3 (häft 1), 1–6.