At last, the rhinogradentians (part I)


I am always surprised when I meet zoologists who aren't familiar with Harald Stumpke's* famous 1957 book Bau und Leben der Rhinogradentia, a volume translated into English by Leigh Chadwick in 1967 as The Snouters: Form and Life of the Rhinogrades (and referred to from hereon as 'Stumpke 1967'). For the few who don't know, this legendary text discusses in marvellous detail the biology, lifestyle and evolution of the snouters (aka rhinogrades or rhinogradentians), a bizarre and unique group of small mammals originally thought endemic to the south Pacific Hi-yi-yi archipelago, an island group discovered by Einar Pettersson-Skamtkvist (umlaut over the a) in 1941 as he escaped from Japanese imprisonment...

* Stumpke has an umlaut over the u: the scienceblogs publishing platform doesn't recognise accents however, hence its absence from my text here.

Little known is that Skamtkvist didn't only discover the rhinogradentians: the islands were also inhabited by the Hooakha-Hutchi people, the bizarre megaphone birds and an endemic shrew, Limnogaloides. A diverse endemic insect fauna was bizarre in including Palaeozoic relicts, and the flora also included archaic forms such as large clubmosses. Of great interest is that rhinogradentians were mentioned in late 19th century European literature, and indeed there is some indication that the Hi-yi-yi islands had actually been discovered by westerners long prior to 1941.

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As evidenced by the bibliography of Stumpke 1967, a substantial number of publications devoted to rhinogradentian morphology, behaviour and evolution appeared during the 1940s and 50s and such was the interest in this group that the Darwin Institute was set up on Hy-dud-dye-fee (the largest island of the archipelago), and an international conference on rhinogradentians held there in 1953 [adjacent image shows conference delegates photographed at the meeting, from here]. In what must be ranked as one of the greatest man-made environmental catastrophes of all time, secretly conducted atomic tests occurring in the same region initiated an earthquake that caused the sudden subsidence and destruction of the entire archipelago. So not only were all the rhinogradentians known at the time made extinct, but all scientists formally specialising on the group were killed. As we'll see later, rhinogradentians have proved not to be endemic to the Hi-yi-yi archipelago as was assumed, and the discovery of new rhinogradentian species has continued to the present, making the group a constant presence in the zoological literature.

What has always bugged me about rhinogradentians is that information on many of the taxa that Stumpke described is impossible to come by, unless that is you're lucky enough to own a copy of Stumpke 1967 (14 family-level taxa and 189 species were named, and the possibility that additional, undiscovered species might have inhabited the archipelago was regarded as likely). Sure, anyone that's really interested in the group will have gone to the trouble of obtaining this work, but because the book is hard to get hold of in many parts of the world, the full diversity of rhinogradentians is not as well appreciated as it might be. A few internet sites discuss rhinogradentian diversity and figure a few of the rarely-discussed species (most notably, this excellent French site), but they fail to cover the more remarkable lineages within the group. In order to amend things, and to bring an understanding of rhinogradentian diversity to a greater audience, my aim here is to briefly review the group's taxonomic diversity. Let me emphasise that I am barely providing a fraction of the information published within Stumpke 1967 however, and if you want in-depth information on the members of the group you must get hold of the book yourself.

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Archirrhinos haeckelii, Haeckel's primitive snouter [shown in adjacent image], was identified by Stumpke as the most basal rhinogradentian. A superficially shrew-like quadruped, it possessed a large nasarium that served as a support when the animal lunged forward to grab prey. Archirrhinos -like ancestors are thought to have given rise to the nasolimacids, the snail-like snouters. While primitively similar to Archirrhinos, nasolimacids evolved a specialised nasarium where the muscles and sinuses were extensively subdivided, thereby allowing the structure to function much like the foot of a snail. These remarkable mammals lived standing on their foot-like nasarium, their bodies sub-vertical and their limbs reduced or modified. They included armour-plated forms as well as the sugarmice Rhinolimaceus, a taxon so named as a gland at its tail base secreted a sweet-tasting fluid.


Probably closely related to the nasolimacids were the rhinocolumnids or pillar-nosed snouters. Again, what was probably the most basal member of the group - the snifflers Emunctator [see adjacent image] - were not all that different from Archirrhinos, though they differed notably from that taxon in using mucosal strands to trap and ingest prey from shallow water. Emunctator possessed a long, mobile tail equipped with a poisonous spur at its tip, and the same character was present in most other pillar-nosed snouters. Among these are the sedentary honeytails Dulcicauda, a group that - like the sugarmice - evolved caudal glands that secreted fragrant secretions that were attractive to insects [Dulcicauda shown at bottom of post]. The pillar-nosed snouters of the short-tailed genus Columnifax developed a remarkable symbiosis with various of the predatory snout leapers, of which we'll see more of later. Columnifax produced milk that the snout leaper drank, while the snout leaper would collect hermit crabs that were eaten by the Columnifax.

What particularly captured the attention of many of those who studied rhinogradentians is that, though descending from shrew-like terrestrial insectivores, they underwent one of the most remarkable adaptive radiations seen among mammals. In addition to the terrestrial forms we've seen so far, there were also fossorial, aquatic and arboreal forms. A morphologically unusual and phylogenetically isolated group, the hypogeonasidans, included both fossorial and aquatic forms. Among the fossorial species were the bizarre ribbon snouters Rhinotaenia: small, blind mole-like rhinogradentians with a bilobed, asymmetrical, tube-like siphonal nasarium. Predominantly animals of tidal sediments, some of them lived almost like parasites within the valves of large bivalves.

Ribbon snouters are generally regarded as closely related to the aquatic rhinostentorids, or trumpet snouters. These also possessed an elongate siphonal nasarium, but their absence of features associated with fossoriality suggests that they never went through a fossorial stage and may instead have descended directed from basal hypogeonasidans that lived at the water's edge. Indeed several derived characters, and a unique sort of mucin secretion, were common to the snifflers and the ribbon snouters, suggesting that the hypogeonasidans evolved from snifflers (Bromeante de Burlas 1952). Trumpet snouters are among the groups that are never mentioned whenever rhinogradentians are discussed. In these forms the nasarium was a funnel-like filtering apparatus, formed into a distal rosette fringed with water-repellent hairs. Stiff bristles lined the naked body. Some species hung suspended from the water's surface while others were pelagic.


Closely related to the hypogeonasidans were the even more remarkable georrhinidans or burrowing snouters, the only group in which the snout was markedly larger than the rest of the body. Basal members of this group are best exemplified by the fossorial mole snouters Rhinotalpa. Equipped with strongly reduced limbs as well as wreaths of stiff bristles around the snout and head, Rhinotalpa used inflation and deflation of its nasarium as well as erection and relaxation of the bristle wreaths to move within its burrows. These features were not present in all members of the genus however, and some (e.g., R. angustinasus) exhibited both tiny size and a highly simplified anatomy: besides a short, simple gut, reduced brain, and absent eyes and nares, they apparently relied on cutaneous respiration [adjacent life-sized Rhinotalpa model from Takeshi Tokiwa's site].


Georrhinida includes what must be among the most amazing of all tetrapods, the holorrhinids (allsnouters), as they were so structurally modified that even their tetrapod identity has been doubted (actually, this is not the first time that members of a rhinogradentian clade have been wrongly identified as invertebrates). The most specialised allsnouter was the Turbellarian-like dwarfsnouter Remanonasus menorrhinus. Just 2 mm long, this tiny worm-like mammal has been regarded by some as a free-living turbellarian flatworm, and in fact Stulten (1955) argued that turbellarians were highly derived rhinogradentians! [adjacent image shows a true turbellarian].

The forms that we've looked at so far all belong to the so-called monorrhinan or uni-snouter and asclerorrhinan or soft-nosed snouter divisions. Among the soft-nosed snouters, the most familiar and best known are the sclerorrhinans, or snout leapers. Equally well known are the members of the last division: the polyrrhinans, or multi-snouters. In the classic phyllogram produced by Bromeante de Burlas (1950), all the major divisions were posited as having originated from a common ancestor in a 'hub and spokes' type arrangement. This might have merit, especially given models that propose an explosive island-endemic radiation of rhinogradentians from a founding ancestor. However, the presence of fossil and extant rhinogradentians in the Old World has shown that all of the major divergences within Rhinogradentia had occurred during the Mesozoic, making the group an ancient one, with a relict distribution in modern times. This argues against the idea of an explosive island-endemic radiation.


Snout leapers and their relatives included numerous terrestrial, arboreal and even volant forms. The most basal forms, the arboreal snout leapers or perihopsids, were likened by Stumpke to arboreally modified kin of Archirrhinos. Their overall proportions were not extraordinary, but their large nasarium was jointed like a limb and possessed a distal plate-like organ. The tail was similarly equipped, providing the animal with similar spring-action pseudo-limbs at both end of the body. Accordingly, perihopsids were reportedly extraordinarily agile, able to leap both forwards and backwards with speed. Presumably derived from a perihopsid-like snout leaper, the hopsorrhinids or true snout leapers were characterised by an extraordinarily long, gracile, jointed nasarium that the animals used to make long backward leaps. The body was particularly short, hindlimbs were entirely absent, and the tail was long, slender and prehensile. Multiple species inhabited the beaches of Hi-yi-yi.

More on rhinogradentians in the next post... [UPDATE: now available here].

Refs - -

Bromeante de Burlas, J. 1950. A derivacao e a arvore genealogica dos Rhinogradentes. Boll. Braz. Rhin. 2, 1203.

- . 1952. The Hypogeonasidae. Bull. Darwin Inst. Hi. 5, Suppl.

Stulten, D. 1955. The Evolution of Turbellarians, a Review of New Aspects. Piltdown University Press.

Stumpke, H. 1967. The Snouters: Form and Life of the Rhinogrades. The Natural History Press, Garden City, New York.


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This brings back memories of reading Stumpke as a grad student. Good times.

I might be wrong, but in a few places you refer to Stumpke 1957 rather than '67.

By John Lynch (not verified) on 31 Mar 2007 #permalink

I'm pretty sure that if you showed me just the pictures of those creates I would have though they were some fantasy concocted by the Greeks or something.

Nature never ceases to amaze.

At last!!!!!
The pictures are superb. Are they original photos? and in that case, what other documentation has survived the nucleoseismic destruction of the Darwin Institute?
This is a true treat. (And thank you for the link to the French site.)

By Allen Hazen (not verified) on 31 Mar 2007 #permalink

Reading that was both disturbing and fascinating! I like the jokey references--"Piltdown University Press" in particular. The snot rehinogradian was perhaps the most disturbing fictional creature I've ever seen (please, please assure me that these are fictional!). I think perhaps you've inspired me to do something similar to this on my own blog. Kudos, sir!

the scienceblogs publishing platform doesn't recognise accents however

That depends on the character encoding used. Scienceblogs seem to be inconsistent. Some use UTF-8, sometimes after asking for technical support, at least in the comments but not always in the Name list script.

If UTF-8 is enabled, diacritics can be produced by HTML code if not encoded by the keyboard. For example, and as a test for this page, "ä" in Skämtkvist is produced by "& # 228 ;" (remove citation marks and spaces; test: ä) or "& auml ;" (remove citation marks and spaces; test: ä).

Spoiler (probably not :-):
"Skämtkvist" means roughly 'Joke-branch' or 'Fake-branch' in swedish. Undoubtedly referring to the animal group at hand.

Can't wait for the next post!

By Torbjörn Larsson (not verified) on 01 Apr 2007 #permalink

An excellent piece of research.

Why weren't these amazing creatures covered on The Life of Mammals? I have already written a letter of complaint to Sir David Attenborough.

...And on the same say that Surgeon claimed to have taken the photo of a giant specimien in loch ness...

(since been proved actualy to have been a vagrant garefowl...)

Just a tip Darren, you can write umlaute (or is the plural of this word in english "umlauts"?) by combining the basal vowel without the points and add an "e", this is sometimes even made in german. So you can write instead of "Stumpke" also "Stuempke".

I have also a great book about the biology of mammals. The whole books is written in a very scientific way and deals with many things such as embryology and many other special topics, but the guy who wrote it, must have a sense of humour, because there is also a short chapter about rhinogradentia, and there is nothing said about their fictional nature...

The rhinogradentians were also important in the Hooakha-Hutchi culture. For example, young girls would catch some Hopsorrhinus, tie them together nose to tail and use them as a living garland. The poison glands at the tips of the tails of Emunctator and other pillar-nosed snouters were used to help catch the magaphone birds. The birds were stuffed with the smaller rhinogradentians and roasted, providing a combination of flavours that had to be tasted to be believed.

Thanks for supplying so much information about these fascinating and useful creatures that are now, alas, lost to us.

By Richard Simons (not verified) on 01 Apr 2007 #permalink

It took me a full minute to figure out this was a joke. Most elaborate, educated April Fools joke I know.

"Skämtkvist" means roughly 'Joke-branch' or 'Fake-branch' in swedish.

Is there an etymological connection to "scam"?

By David Marjanović (not verified) on 01 Apr 2007 #permalink

Thanks, Darren, for finally posting about the snouters.

Sordes: I believe I saw the book to which you refer, many years ago, and I wondered if the author knew the Rhinogradentia was a joke.

I first read Stumpke in grad school. I had no idea someone was making museum-quality models of snouters. What are your photo sources on those?

In a neurobiology class, years ago, a trio of classmates and myself wrote a report and presentation about the probable neuromuscular architecture of the flight structures of one flying species of Rhinogradentians. One member of our group has now, to the best of my knowledge, completed a PhD in robotics (simulation of biological systems). He presented the electoneural diagram of the flight oscillation circuits to the class.

We got an A+, and I will always remember these mammals fondly.

Is there an etymological connection to "scam"?


Well, perhaps. "Skämt" comes from the verb "skämta", and this (and some very similar words) apparently originates in german root "skammatjan". It seems to originally roughly mean 'shorten time'.

And it comes through old swedish "skamber", related to icelandic "skammr" and old german "scam(m)" or "scemmi". ( )

But on the english side it is worse.

"The Oxford English Dictionary also says the origin is obscure, but it claims that the word originated in the U.S." ( )

"scam etymology
[Origin unknown.]"
( )

By Torbjörn Larsson (not verified) on 03 Apr 2007 #permalink

AT LAST! Good date too...

Where did you find the models??

Sordes: in Flannery and Schouten's Astonishing Animals, one of the fantastic creatures is a hoax. Readers of this blog will doubtless be able to pick it out but it is not easy!

yes, indeed -- where do the photos/models come from? (and where is my favourite rhinograde, the nasobame? shall look at the second installment presently to check if it's mentioned there.)

Great article :-)

I'm teaching comp. vertebrate anatomy this semester and intend to use rhinogrades as examples whenever I get bored with more conventional species.

If anyone is interested, 2nd hand copies of Stumpke's book are available online and are relatively inexpensive.

All the best!

I did not read all comments... may be a person pointed yet that the most surprising fact is, when the book was released on 1961 by Masson at Paris, several workers said the "true" author was the well-known and "straight worker" Pr Pierre-Paul Grassé... Till to-day, we ignore if he is (or not) the author of this fantastic book ! As you can read in the french website, a photo of one specimen was recently taken in the archipielago... !
(We are waiting for a phyletic study on the Bigfoot family, the living dinosaurs of several seas, and the Yeti too...)
More :
I just want to point the interesting study I got from a brasilian worker, Antonio Santos-Silva : Baker and Timm, 1976 Modern types concepts in Entomology (pdf file).

By Fortuné Chalumeau (not verified) on 26 Mar 2010 #permalink

we ignore if he is

We don't know if he is. French ignorer usually just means "to not know".

By David MarjanoviÄ (not verified) on 26 Mar 2010 #permalink