STELLER'S SECRET FAUNA – GARGANTUAN SEA-COWS, INACCESSIBLE SEA-RAVENS, AND BEWHISKERED SEA-MONKEYS

Steller's sea-cows (© William Rebsamen)

Dr Georg Wilhelm Steller was a German physician and naturalist participating during the early 1740s in the last of Danish explorer Vitus Bering's Russian expeditions to the Arctic waters (now called the Bering Sea) separating Siberia's Kamchatka Peninsula from Alaska. During this expedition, Steller documented many new species of animal, including four very contentious forms that continue to arouse cryptozoological curiosity even today. I have already documented one of these, Steller's sea-bear, on ShukerNature (click here), so here now are the other three.

SURVIVING SEA-COWS?

Distantly related to elephants, the manatees and dugongs are herbivorous aquatic mammals known as sirenians, with fish-like tails, no hind limbs, and flippers for forelimbs. Nowadays, the largest living sirenian is the Caribbean manatee Trichechus manatus, which is up to 15 ft long, but there was once a much bigger species, called Steller's sea-cow Hydrodamalis gigas (=Rhytina stelleri). Measuring up to 30 ft long and weighing several tons, this gigantic sea mammal was discovered in 1741 in the shallow waters around Copper Island and nearby Bering Island - named after Vitus Bering, whose expedition was virtually wrecked here that year. While marooned on this island, Steller studied the sea-cows (the only scientist ever to do so), which existed in great numbers, but the other sailors slaughtered them for food.

Georg Steller's own drawing of the giant sea-cow species named after him

When he returned to Kamchatka with news of this enormous but inoffensive species, it became such a greatly-desired source of meat for future sea travellers that by 1768 - just 27 years after Steller had first discovered it - every single sea-cow appeared to have been killed. Not one could be found alive, and since then science has classified this species as extinct. Every so often, however, sailors and other maritime voyagers journeying through the icy waters formerly frequented by Steller's sea-cow have spied extremely large, unidentified creatures closely resembling this officially vanished, giant sirenian.

In 1879, while exploring the polar waters traversed more than a century earlier by Steller, Swedish naturalist Baron Erik Nordenskjöld visited Bering Island in his vessel, Vega. He was startled to learn from one islander, Pitr Vasilijef Burdukovskij, that for the first 2-3 years after his father had settled here from mainland Russia in 1777, sea-cows were still being seen - and were still being killed, to use their tough hides for making baydars (native boats).

Local postage stamp depicting a Steller's sea-cow, issued by the Commander Islands

Even more intriguing was the testimony of two other islanders, Feodor Mertchenin and Nicanor Stepnoff, who claimed that as recently as 1854, they had encountered on the eastern side of Bering Island a very large sea mammal wholly unfamiliar to them - which had brown skin, no dorsal fin, small forefeet, and a very thick forebody that tapered further back. It blew out air, but through its large mouth instead of through blow-holes like a whale, and about 15 ft of its body's length rose above the water surface as it moved.

Nordenskjöld was sure that they had seen a Steller's sea-cow, because their description contained details of sea-cow morphology given in Steller's documented account, which they had never seen. However, when Stepnoff was later interviewed by American researcher Leonhard Stejneger, he concluded that the creature encountered by them had actually been a female narwhal Monodon monoceros (that famous species of toothed whale whose males characteristically possess a single long spiralled tusk, once believed to be the unicorn's horn). Stejneger also felt that Nordenskjöld had misunderstood Burdukovskij's statement regarding when his father had settled on Bering Island, and considered that the correct date was 1774, not 1777.

Model of a Steller's sea-cow prepared by Markus Bühler (© Markus Bühler)

In 1911-1913, a fisherman claimed to have seen a dead Steller's sea-cow, brought in by the sea current towards the Cape of Chaplin on Siberia's easternmost tip, close to the Bering Strait. Frustratingly, this potentially sensational discovery was never investigated.

Perhaps the most compelling sighting occurred in July 1962 near Cape Navarin, south of the Gulf of Anadyr, lying northeast of Kamchatka's coast. Six strange animals were spied in shallow water by the crew of the whaling ship Buran about 300 ft away. They were said to be 20-26 ft long, with dark skin, an upper lip split into two sections, a relatively small head clearly delineated from its body, and a sharply-fringed tail. Scientists postulated that these animals must have been female narwhals. However, the description provided by the Buran whalers fits Steller's sea-cow more closely than a female narwhal, and it seems unlikely that experienced whalers would fail to recognise such a familiar creature.

Engraving of a Steller's sea-cow from 1886

In summer 1976, some salmon factory workers at Anapkinskaya Bay, just south of Cape Navarin, reported seeing, and actually touching, the carcase of a stranded sea-cow. One of them, Ivan Nikiforovich Chechulin, was interviewed by Vladimir Malukovich from the Kamchatka Museum of Local Lore, and stated that the mysterious animal had very dark skin, flippers, and a forked tail. Reaching out to touch this creature, they had noticed that it also had a prominent snout. When Malukovich showed Chechulin various pictures of sea creatures to assist him in identifying what he and his colleagues had seen, the creature whose picture he selected as corresponding with their mystery beast was Steller's sea-cow.

In the late 1970s, British explorer Derek Hutchinson launched an expedition to search for sea-cows off the Aleutian Islands, as did Soviet physicist Dr Anatoly Shkunkov in the early 1980s off Kamchatka. Neither met with success. Even so, as speculated by cryptozoologists such as Professor Roy P. Mackal in his book Searching For Hidden Animals (1980), and Michel Raynal (INFO Journal, February 1987), some sea-cows may have avoided annihilation by moving away from their former haunts, into more remote regions - of which the freezing waters and bleak coastlines around Kamchatka, the Aleutians, and elsewhere in this daunting polar wilderness are plentifully supplied yet extremely difficult to explore satisfactorily.

STELLER'S SEA-RAVEN – UNMASKED BUT UNRECOGNISED?

Whereas Steller's sea-cow, even if indeed extinct today, has been extensively documented and is physically represented in museums by skeletal material, we still have next to nothing on file (let alone in the flesh) concerning Steller's most cryptic avian discovery.

While shipwrecked on Bering Island during 1741-42, Steller briefly referred in his journal to a mystifying species that he called a "white sea-raven" - a rare bird "...not seen in the Siberian coast...[and which is] impossible to reach because it only alights singly on the cliffs facing the sea". However, this species has never been formally identified; nor does it appear to have been reported again by anyone else. So what could it be?

Surfbird (© Marlin Harms/Wikipedia)

Seeking an answer to this baffling riddle, I communicated in June 1998 with cryptozoological enthusiast Chris Orrick, who has made a special study of Steller's own publications and other Steller-related works. Chris speculated that Steller's white sea-raven may actually be some species that is known to science today, but was unknown at least to Europeans back in the early 1740s - possibly a species native to the Aleutians but rarely if ever seen around Kamchatka. One candidate offered by Chris was the surfbird Aphriza virgata, a white-plumaged wader from Alaska and America's western Pacific that may not have been familiar to Steller.

Danish cryptozoologist Lars Thomas from Copenhagen's Zoological Museum was also intrigued by the mystery of the white sea-raven's identity, and he has offered me his own opinion regarding it. Steller was German, and Lars pointed out that cormorants are referred to in German as sea-ravens. Indeed, a hitherto unknown species of cormorant, the now-extinct spectacled cormorant Phalacrocorax perspicillatus, discovered by Steller during this same expedition, was referred to by him as a sea-raven.

Spectacled cormorant, painted in 1869 by Joseph Wolf

Consequently, Lars argued that Steller's mention of a white sea-raven may in reality refer to a white cormorant (either an albino or a young specimen, as some juveniles are much paler than their dark-plumed adults).

Alternatively, it may be a bird that superficially resembles a white cormorant, such as the pigeon guillemot Cepphus columba in winter plumage, or possibly even a vagrant gannet or booby.

Pigeon guillemot (© Yathin S. Krishnappa/Wikipedia)

During our communications, Chris revealed that in a letter to the Russian Academy, dated 16 November 1742, Steller announced that he had prepared and sent two scientific papers - one dealing with North American birds and fishes, the other with Bering Island's birds and fishes. In view of Steller's meticulous manner of documentation, it is likely that the latter paper would have contained a detailed description of the white sea-raven. Unfortunately, however, neither of these manuscripts is known today, but they may still exist, albeit possibly unrecognised, amid the Academy's vast archives in St Petersburg.

Unless these or other additional 18th Century documents on this incognito seabird are uncovered, however, its identity will probably never be exposed. Ironically, as Chris noted, we may already know what Steller's sea-raven is, but without realising that we know!

THE MANDARIN-WHISKERED SEA-MONKEYS OF STELLER AND SMEETON

None of the many creatures documented by Steller, however, is as curious, or controversial, as the bizarre animal observed by him for over 2 hours during the afternoon of 10 August 1741, at approximately 52.5°N latitude, 155°W longitude. He described it as follows:

It was about two Russian ells [about 5 ft] in length; the head was like a dog's, with pointed erect ears. From the upper and lower lips on both sides whiskers hung down which made it look almost like a Chinaman. The eyes were large; the body was longish round and thick, tapering gradually towards the tail. The skin seemed thickly covered with hair, of a gray color on the back, but reddish white on the belly; in the water, however, the whole animal appeared entirely reddish and cow-colored. The tail was divided into two fins, of which the upper, as in the case of sharks, was twice as large as the lower. Nothing struck me more surprising than the fact that neither forefeet as in the marine amphibians nor, in their stead, fins were to be seen...For over two hours it swam around our ship, looking, as with admiration, first at the one and then at the other of us. At times it came so near to the ship that it could have been touched with a pole, but as soon as anybody stirred it moved away a little further. It could raise itself one-third of its length out of the water exactly like a man, and sometimes it remained in this position for several minutes. After it had observed us for about half an hour, it shot like an arrow under our vessel and came up again on the other side; shortly after, it dived again and reappeared in the old place; and in this way it dived perhaps thirty times.

After watching this extraordinary creature frolicking comically in the water with a long strand of seaweed for a time, Steller, greatly desiring to procure their strange sea visitor in order to prepare a detailed description, loaded his gun and fired two shots at it. Happily, the animal was not harmed, and swam away, though they saw it (or another of its kind) on several subsequent occasions in different stretches of the sea.

Reconstruction of the possible appearance of Steller's sea-monkey (© Craig Gosling)

No known species corresponds with Steller's description of this peculiar beast, which became known as Steller's sea-monkey or sea-ape. Moreover, until fairly recently, no further sighting of such a creature had ever been reported either, leading scientists to speculate that whatever it had been, its species must surely now be extinct. On a clear afternoon in June 1965, however, eminent British yachtsman-adventurer Brigadier Miles Smeeton was sailing by the central Aleutian Islands aboard his 46-ft ketch Tzu Hang, with his wife, daughter, and a friend aboard, when he and the others sighted a remarkable sea-beast.

As since documented by explorer-journalist Miles Clark (BBC Wildlife, January 1987), lying in the water close off the port bow was what seemed to be a 5-ft-long animal with 4-5-in-long reddish-yellow hair, and a head more dog-like than seal-like, whose dark intelligent eyes were placed close together, rather than set laterally on the head like a seal's. Indeed, Henry Combe, the Smeetons' friend aboard their ketch, stated that it had a face rather like a Tibetan shih-tzu terrier "...with drooping Chinese whiskers". As the vessel drew nearer, this maritime mandarin "...made a slow undulating dive and disappeared beneath the ship". No-one spied any limbs or fins. Their observation of it had lasted 10-15 seconds, and they have remained convinced that it was not a seal. Although sea otters occur in these waters, this creature did not resemble any sea otter previously spied by them either.

An alternative reconstruction of Steller's sea-monkey (© Tim Morris)

Conversely, it closely corresponds with Steller's description over two centuries earlier of his mystifying sea-monkey, thereby giving cryptozoologists hope that its species still exists. As for its identity, however, there is still no satisfactory explanation. Its inquisitive, playful, intelligent, supremely agile behaviour are all characteristics of seals and otters, yet Smeeton and his fellow observers are convinced that their creature was neither of these, and it certainly does not bear any immediate resemblance to such animals - set apart by its apparent absence of forelimbs, its asymmetrical vertical tail, and its mandarin-style whiskers. Equally, it seems highly improbable that any wildlife observer as experienced and as meticulously accurate in chronicling his observations afterwards as Steller would fail to recognise it as a type of seal or otter if this is truly all that it was. In fact, Steller was so perplexed by the creature that he made no attempt whatsoever to classify it.

Via independent lines of research, Chris Orrick and Jay Ellis Ransom, formerly executive director of the Aleutian-Bering Sea Expeditions Research Library in Oregon, have both formulated theories that Steller's sea-monkey may have been a vagrant specimen of the Hawaiian monk seal Monachus schauinslandi - one that had wandered north far from its normal Hawaiian archipelago domain. Chris also suggests that it may have been undergoing its annual moult at the time, explaining its fur's appearance as documented by Steller. Nevertheless, it still requires an appreciable stretch of the imagination to convert the sea-monkeys described here into any form of seal, Hawaiian monk or otherwise.

Hawaiian monk seal resting vertically in the water (public domain)

Perhaps one day a zoologist voyaging in the Bering Sea will espy Steller's most enigmatic discovery, which seems still to survive in these frigid waters, and in so doing may finally resolve a fascinating zoological mystery that has persisted for more than 250 years.

This ShukerNature post is excerpted from my book Mysteries of Planet Earth.

SPOTTING A LEOPARD MARTEN ON EBAY

Spotted marten, full view, right-hand side (© Gabriele Lüke)

The global internet auction site Ebay may not seem a particularly likely source of anomalous animal specimens, but over the years some undeniably intriguing examples have turned up on it – from mouse-sized 'venomous water elephants' from Thailand (hoaxes) and a stuffed skunk ape head (hoax) to alleged bigfoot hair (?) and some sea urchins that were found to belong to a species hitherto-undescribed by science (true!).

The most recent addition to this exclusive if eclectic company was kindly brought to my attention on 16 December 2014 by Facebook friend Martin Cotterill. Listed on Ebay's German site, it consisted of a taxiderm marten specimen, but unlike any marten conceived by Mother Nature, this particular individual sported spots - a distinctly eyecatching pelage liberally dappled with large black blotches and also boasting a genet-like or even leopardesque background colouration. Indeed, as I stated when posting the images of this wonderful animal on my own Facebook timeline, if a marten could hybridise with a genet (which it can't!) the offspring might look something like this!

Spotted marten, front view (© Gabriele Lüke)

Obviously it was a fake, and in its Ebay listing's description its seller openly stated that it had been treated to look like a miniature leopard, so its spots had been deliberately added to it (in a decidedly professional, naturalistic manner too, I might add). Consequently, it was not an attempt to hoax anyone, merely to delight – which this veritable leopard marten definitely did. So much so that it attracted a sizeable number of watchers and bidders, and finally sold (on 21 December) for the very hefty price-tag of 208.88 euros! Click here to see its original listing while it is still online – like that of all sold items on Ebay, the listing will disappear within the next month or so.

Prior to its sale, however, and anxious to learn more about it but aware that my fluency in German has its limitations, I asked German cryptozoologists Markus Bühler and Markus Hemmler if they would make some enquiries on my behalf to the seller regarding this fascinating specimen, with particular emphasis upon the precise technique used to apply its coat's spotting in such an impressively naturalistic, expert way. Both of them very kindly did so (thanks guys!), and discovered that this spotted marten's seller was also its creator – a notable German artist called Gabriele Lüke.

Spotted marten, full view, left-hand side (© Gabriele Lüke)

Gabriele stated to Markus Hemmler that she had no objection to my writing about the marten. However – and, albeit frustratingly but totally understandably too – she did not wish to reveal the nature of her technique for applying the spots to its pelage, because it is one to which she has devoted much time and money.

I had a very specific reason for wanting to learn how the spotting had been achieved so masterfully, a reason relating to a certain animal anomaly that has intrigued me for quite some time (and which I plan to document fully in a future ShukerNature post), but naturally I fully appreciate and accept Gabriele's wish for secrecy concerning her own particular technique. I also thank her most sincerely for so kindly permitting me to document her maculate marvel, and I hope that its successful bidder will treasure this unique, delightful animal.

If only such a photogenic creature truly existed – even the giant panda, Bambi, and the Andrex puppy might well struggle to compete with a leopard marten in the cuteness stakes!

Spotted marten, dorsal view (© Gabriele Lüke)

PERUSING THE PACARANA - A TERRIER-SIZED ‘TERRIBLE MOUSE’

A captive pacarana (public domain)

There are over 2,200 species of modern-day rodent currently known to science, but only a handful are so radically different from all others that they have been assigned an entire taxonomic family all to themselves. However, the extraordinary – and exceptionally large - rodent documented here (and which also happens to be one of my favourite mammals) has indeed received that rare accolade. Moreover, as will now be revealed, the history of its scientific discovery - and rediscovery - is just as remarkable as it is.

The year 1904 was a momentous year for mice, for it marked the rediscovery of a truly astonishing and extremely mysterious, controversial rodent that science had dubbed 'the terrible mouse', due to the fact that it was as large as a fox terrier!

Needless to say, any mouse the size of a small dog is no ordinary mouse, and in truth this species is not a bona fide mouse at all. If anything, it more closely resembles a long-tailed, spineless porcupine in general shape, and sports a handsome grey-black pelage decorated with longitudinal rows of white spots, which compares well with that of the South American common paca or spotted cavy Cuniculus paca, which is a fairly large relative of the guinea pig (but not the world's third largest rodent, as certain websites erroneously claim).

Common pacas (© HumedoTepezc/Wikipedia)

Indeed, in its native Andean homeland, the 'terrible mouse' is known locally as the pacarana ('false paca'). Yet it is neither paca nor porcupine either. Instead, as noted above, it is sufficiently removed from all living rodents to require its very own taxonomic family, Dinomyidae, thereby making it one of the most important mammalian discoveries of the past 150 years - not to mention one of the most elusive. Several prehistoric relatives of the pacarana have subsequently been described from fossil remains, and some of these were quite enormous in size (one, Josephoartigasia monesi, which lived 4-2 million years ago during the Pliocene and early Pleistocene epochs, was the size of a bison and is the largest rodent presently known to have existed). However, no other living dinomyids have been discovered, thus making the pacarana the very last representative of its entire lineage.

Josephoartigasia monesi reconstruction inspired by the pacarana (© Nobu Tamura/Wikipedia)

Measuring up to 100 cm long and weighing as much as 15 kg, the pacarana is the world's third largest living rodent (exceeded only by the capybaras and beavers – but not by the paca, see above), and was discovered in 1873 by Prof. Constantin Jelski, curator of Poland's Cracow Museum. Financed by Polish nobleman Count Constantin Branicki, Jelski was engaged in zoological explorations in Peru when, one morning at daybreak, he observed an extremely large but wholly unfamiliar rodent. It had very long whiskers and a fairly lengthy tail, and was wandering through an orchard in the garden of Amablo Mari's hacienda near Vitoc, in the eastern Peruvian Andes. He swiftly dispatched the poor creature, and sent its skin and most of its skeleton back to Warsaw, where it gained the attention of Prof. Wilhelm Peters, Berlin Zoo's director, who meticulously studied its anatomy. Recognising that this huge rodent represented a dramatically new species, by the end of 1873 he had published a scientific description of it, in which he named it Dinomys branickii - 'Branicki's terrible mouse'. The pacarana had made its scientific debut.

19^th-Century engraving of the pacarana specimen encountered by Jelski

Peters's studies disclosed that its anatomy was a bewildering amalgamation of features drawn from several quite different rodent families. In terms of its pelage and limb structure, it compared well with the paca, but unlike the five-toed (pentadactyl) configuration of the latter's paws the pacarana's each possessed just four toes. Many of its cranial and skeletal features (not to mention its long, hairy tail) also set it well apart from the paca, especially the flattened shape of the front section of its sternum (breast bone), and the development of its clavicles (collar bones).

19^th-Century engraving of the common paca for comparison purposes with the previous engraving of a pacarana

Certain less conspicuous features of its anatomy were reminiscent of the capybara, but various others (including the shape of its molar teeth) corresponded most closely with those of the chinchillas. There were also some additional characteristics that seemed to ally it with the West Indies’ coypu-like hutias. Little wonder then that Peters elected to create a completely separate taxonomic family for it!

The pacarana was clearly a major find - yet no sooner had it been discovered than it vanished. For three decades nothing more was heard of this 'false paca', and zoologists worldwide feared that it was extinct.

Dr Emil Goeldi (public domain)

Then in May 1904, Dr Emilio Goeldi (1959-1917), director of Brazil's Para (now Belem) Museum, received a cage containing two living pacaranas (an adult female and a subadult male). These precious animals had been sent from the upper Rio Purus, Brazil, and proved to be extremely docile, inoffensive creatures, totally belying their 'terrible mouse' image. They were swiftly transferred to Brazil's Zoological Gardens, but tragically the adult female died shortly afterwards, following the birth of the first of two offspring that she was carrying.

Rare, early 20^th Century photograph of a captive pacarana

In 1919, a more unusual-than-normal pacarana was described by Alipio de Miranda Ribeiro. Instead of being greyish-black in colour, it was brown, so Ribeiro designated it as the type specimen of a new species, christened D. pacarana. Three years earlier, the first pacarana recorded from Colombia had been collected (near La Candela, Huila); in 1921, this became the type of a third species, D. gigas. During the early 1920s, a series of pacaranas was procured by Edmund Heller from localities in Peru and also Brazil, so that by the 1930s a number of museum specimens existed, which were then examined carefully by Dr Colin Sanborn in the most detailed pacarana study undertaken at that time. Publishing his findings in 1931, he revealed that D. pacarana and D. gigas were nothing more than varieties of D. branickii, which meant that only a single species existed after all.

Brown-furred (or faded black-furred?) taxiderm pacarana specimen at the Berlin Natural History Museum (© Markus Bühler)

A rarely-glimpsed, nocturnal inhabitant of mountain forests, the pacarana feeds on leaves, fruit, and grass, usually associates in groups of four and five, and is hunted as a source of food by its Indian neighbours, but little else is known about its lifestyle in the wild state. It is currently classed as a vulnerable species by the IUCN, yet as a result of its secretive habits and relatively inconspicuous habitat it may be more abundant than hitherto suspected (nowadays it is known to be fairly common, for instance, in Bolivia’s Cotapata National Park).

Taxiderm pacarana at Tring Natural History Museum, Hertfordshire, England (© Dr Karl Shuker)

Due to this species’ notoriously elusive nature, however, down through the years zoos have prized pacaranas almost as much as giant pandas - which is why early 1947 was a singularly memorable time for Philadelphia Zoo. It was then that it received an innocuous-looking crate from legendary animal dealer Warren Buck of Camden, New Jersey, with the laconic remark: “Here’s a new one on me. Maybe you know what it is”. When the crate was opened, to everyone astonishment it contained a living pacarana! And just like Goeldi’s twosome, it proved to be delightfully tame and affectionate, showing no inclination to bite, and liking nothing better than to greet its visitors with a cheerful grunt and to sit upright on its hindlegs crunching a potato or carrot gripped firmly between its forepaws.

Of the handful of captive pacaranas obtained more recently and exhibited at such zoos as Zurich (the first to breed them), Basle, and San Diego (where I was fortunate enough to see my first live pacaranas in 2004), most have been of similarly pacific temperament. Indeed, they actively seek out their human visitors to nuzzle them and rub themselves against their legs almost like cats, or even to be picked up and carried just like playful puppies - truly a species with no desire whatsoever to live up to its formidable Dinomys designation!

Pacarana depicted on a postage stamp issued by Equatorial Guinea

Finally: Demonstrating that not only the pacarana but also the true pacas may well have some extra-large surprises in store for science is an exciting recent discovery made in Brazil by Dutch zoologist Dr Marc van Roosmalen. There are three currently-recognised species of true paca. Namely: the above-mentioned common paca C. paca; the smaller, longer-furred, and less-familiar mountain paca C. taczanowskii; and Hernandez's mountain paca C. hernandezi, described and named as recently as 2010 after mitochondrial DNA analyses confirmed its separate taxonomic status from the mountain paca. These are almost-tailless rodents normally no more than 60 cm long (often less), averaging 7 kg in weight, and adorned with usually four longitudinal rows of white spots on each side of their blackish-brown-furred body

Mountain paca (© WebmasterRioblanco/Wikipedia)

However, just a few years ago, Marc encountered – and collected – in Brazil a much larger form of true paca, known locally as the paca concha. It appears to have a very wide distribution range, and is distinguished from the two recognised species by its greater size (weighing up to 13 kg), its lighter fur colour, and the merging of most of its spots into longitudinal lines.

The holotype of the currently-undescribed giant paca (© Dr Marc van Roosmalen)

In a scientific paper currently awaiting publication, Marc has named this extra-large form as a new species. Several suspected specimens of giant paca are held at Brazil’s Museu Paraense Emilio Goeldi, where Marc’s holotype of this potential new species, killed for food by a local hunter on 28 May 2006 near Tucunaré, has been deposited. So perhaps Count Branicki’s false paca now has a rival among the real pacas in terms both of physical stature and of complete surprise to the zoological community, thanks to its unexpected discovery.

This ShukerNature post is an expanded version of my pacarana account in my Encyclopaedia of New and Rediscovered Animals.

HORNED RODENTS, DEVIL'S CORKSCREWS, AND TERRIBLE SNAILS - REAL-LIFE PALAEONTOLOGICAL DETECTIVE STORIES

As a small child, this is the first picture that I ever saw of Ceratogaulus – in my trusty How and Why Wonder Book of Prehistoric Mammals, 1964 (© John Hull/Transworld – reproduced bere on a strictly non-commercial Fair Use basis for educational/review purposes only)

Horned rodents, devil's corkscrews, and terrible snails may not seem to have a lot in common, but in reality these three ostensibly separate strands are intricately intertwined within a singularly unusual, interesting chapter in the history of zoological discovery, as now revealed.

It all began in 1891, when geologist Dr Erwin H. Barbour from the University of Nebraska was shown some extraordinary formations by local rancher Charles E. Holmes in the Badlands of northwestern Nebraska, USA. Holmes and Dr Barbour colloquially dubbed them 'devil's corkscrews', as they did indeed resemble gigantic subterranean screws, each one penetrating several metres below the earth's surface, and constituting an elongated spiral of hardened earth.

Daimonelix, illustration from 1892 (public domain)

Dr Barbour proposed that these were the fossilised remains of giant freshwater sponges, his theory having been influenced by the belief current at that time that the deposits in which they occurred, and which dated to the Miocene epoch approximately 20 million years ago, were the remains of a huge freshwater lake,

Moreover, recalling the informal 'devil's corkscrew' nickname that he and Holmes had coined for them, in a short paper published by the journal Science in 1892 Barbour gave to these perplexing structures the formal scientific name Daimonelix ('devil's screw'), sometimes spelled Daimonhelix or Daemonelix in later works. Not everyone, however, was convinced by his theory that they were prehistoric sponges.

Daimonelix diagram from Barbour's 1892 paper (public domain)

A number of authorities favoured the possibility that they were artefacts, each one having been created by the intertwining of roots from some form of prehistoric plant that had subsequently rotted away (or even by pairs of prehistoric plants, one coiling tightly around the other), with the spiral-shaped space that they had left behind becoming filled with mud, ultimately yielding one of these remarkable giant underground 'screws'. And once subsequent research had shown that the deposits containing them were not the remains of a lake at all but were associated with semi-arid grassland instead, even Barbour quietly abandoned his freshwater sponge proposal in favour of the plant theory.

However, the name Daimonelix remained valid, because although scientific genera and species names are generally given only to organisms (modern-day or fossil), a notable exception to this nomenclatural rule concerns ichnofossils or trace fossils. These are fossils not of organisms themselves but of the traces left behind by them, such as footprints, burrows, coprolites, feeding marks, plant root cavities, etc, and they too receive scientific genera and (sometimes) species names.

Daimonelix, fossil rodent burrow, Sioux County, Nebraska, Early Miocene, close-up (public domain)

A third theory concerning the nature of the devil's corkscrews was put forward by Dr Theodor Fuchs and Edward Drinker Cope, who independently suggested in 1893 that they were the fossilised burrows of a Miocene rodent. This notion attracted appreciable interest – but if true, what kind of rodent could have been responsible? One candidate favoured in various popular-format publications for quite some time during the 20^th Century was a creature no less extraordinary than the corkscrews themselves.

In 1902, Dr William D. Matthew published a paper in the Bulletin of the American Museum of Natural History in which he formally described a new species of fossil rodent hailing from Colorado and dating back to the Miocene, but which was so different from all previously recorded species that it also required the creation of a new genus. Based upon a skull found in 1898, he named this novel creature Ceratogaulus rhinocerus – a very apt name, because, unique among all rodents at that time, it bore a pair of short but very distinctive vertically-oriented horns, sited laterally upon the dorsal surface of its nasal bones' posterior section.

Ceratogaulus [aka Epigaulus] hatcheri, illustration from 1913 (public domain)

In later years, three additional horned species were discovered and named – Ceratogaulus anecdotus, C. hatcheri, and C. minor. Some of these were initially housed in a separate genus, Epigaulus (created in 1907), and C. minor has been reassigned by some workers to the related genus Mylagaulus, but the current consensus is that all four belong to Ceratogaulus. In addition, a fifth horned species, but which unequivocally belongs to the genus Mylagaulus rather than Ceratogaulus, was scientifically described as recently as 2012. Named Mylagaulus cornusaulax, it lived in western Oklahoma during the Miocene. Four other Mylagaulus species (not counting C. minor if classed as belonging to this genus) are also known, but none of these was horned.

Known technically and collectively as mylagaulids, the horned rodents and several closely-related genera of non-horned species constitute an entirely extinct taxonomic family, existing from the Miocene to the Pliocene and (in the case of the horned species) unique to North America, but belonging to the squirrel lineage of rodents (Sciuromorpha). Moreover, examination of complete and near-complete skeletal remains has revealed that they superficially resembled marmots and other ground squirrels too, both in size (measuring roughly 60 cm long) and in overall appearance – except of course for the five horned species' nasal horns, which make them the smallest horned mammals known to science. The horned species are sometimes colloquially referred to as horned gophers, but this is a misnomer, because gophers are only very distantly related to them. 'Horned marmot' would be a much more appropriate name.

Two Ceratogaulus specimens and a prehistoric hare (public domain)

Suggestions that the devil's corkscrews could be the fossilised remains of burrows excavated by these rodents, utilising their horns, attracted interest, and remained in contention as the solution to this longstanding mystery until as recently as the 1970s (my little How and Why Wonder Book of Prehistoric Mammals was still supporting it back in 1964). However, studies focusing upon the precise conformation of their horns and speculating upon what this conformation indicated in relation to their possible functions revealed that such an idea was inherently and fatally flawed. Both the position and the shape of the horns are inconsistent with their being efficient digging tools.

By being located on the posterior rather than the anterior section of the nasal bones, the horns could not be used for digging through earth without the animal's muzzle constantly getting in the way, severely impeding the efficiency of this activity. Moreover, in later species the horns were positioned even further back than in the earlier ones, so it is evident that these rodents' evolutionary development became increasingly contrary to their horns being used as digging tools. The horns' very broad, thick shape also argued persuasively against their effectiveness as digging tools (it is nowadays believed that they served as defensive weapons instead). And so too did the telling fact that no remains of horned rodents discovered in direct association with devil's corkscrews had ever been documented.

Ceratogaulus hatcheri skeleton (© Ryan Somma/Wikipedia)

But if the horned rodents were not responsible for these structures, then what was? As far back as 1905, Dr Olaf A Peterson from the Carnegie Museum had revealed that some of them contained fossilised bones from Palaeocastor fossor and P. magnus - two prehistoric species of small terrestrial beaver. They had existed in Nebraska and elsewhere in North America's Great Plains region during the late Oligocene and Miocene epochs. However, it was not until 1977 that their responsibility for creating the devil's corkscrews was confirmed, via a scientific paper published in the journal Palaeogeography, Palaeoclimatology, Palaeoecology, and authored by Drs Larry D. Martin and D.K. Bennett.

In it, the authors disclosed that these enigmatic underground spirals were in fact the helical shaft sections of Palaeocastor burrows, each complete burrow consisting of a single entrance mound, a long spiralled shaft, and a lower living chamber. These burrows also possessed interconnecting side-passages, and the authors' paper revealed that very extensive subterranean Palaeocastor colonies had existed (Dr Martin had discovered one that contained over 200 separate burrows), which were comparable in size and network complexity to the underground labyrinthine 'towns' or 'cities' produced by those modern-day North American ground squirrels known as prairie dogs.

Palaeocastor reconstruction (© Nobu Tamura/Wikipedia)

In addition, Martin's research at the University of Kansas had uncovered that the beavers excavated these screw-shaped burrow shafts with their incisor teeth, not with their claws (as various previous proponents of a rodent origin for such structures had wrongly assumed). For instead of finding narrow claw marks on the burrow walls, which is what he had expected, Martin instead discovered numerous broad grooves – which he was able to duplicate exactly by scraping the incisors of fossil Palaeocastor skulls into wet sand. The very regular spirals of their burrows' shafts (i.e. the devil's corkscrews) had been constructed by the beavers via a continuous series of either left-handed or right-handed incisor strokes.

And as final proof that Palaeocastor was indeed the engineer of the devil's corkscrews, the wider chambers immediately below these spiralled shafts were sometimes found to contain perfectly-preserved fossil skeletons of adult beavers and beaver cubs, thereby verifying that they were indeed the burrows' living quarters for these beavers.

Palaeocastor fossil remains inside burrow's living chamber (public domain)

After almost a century, the mystery of North America's devil's corkscrews was a mystery no more; but across the Atlantic in England, an equally spectacular edifice of spiralled structure has continued to baffle the scientific world. Its name? Dinocochlea – 'the terrible snail'.

In 1921, during the construction of a new arterial road near Hastings in the Wealden area of Sussex, an enormous spiral-shaped object was uncovered and excavated from early Cretaceous clay after having been spotted by site engineer H.L. Tucker. Outwardly it resembled the spiralled shell of certain marine gastropod molluscs, in particular those of the genus Turritella, which is represented by numerous living and fossil species.

Fossil Turritella specimens (public domain)

Accordingly, when it was formally described in 1922 by London's Natural History Museum molluscan specialist Dr Bernard B. Woodward within the Geological Magazine, he named it Dinocochlea ingens, and did indeed categorise it as a fossil gastropod, albeit one of immense proportions.

Measuring more than 2 m in length, it was far bigger than any other gastropod species known then, or now. However, this identification incited much controversy.

Dinocochlea in situ (public domain)

For whereas spiralled gastropod shells normally bear ridges and possess coils that taper to a point,  Dinocochlea did not, and there were no shell traces preserved with it either. Its freakishly large size was also difficult to reconcile with a gastropod identity.

Recalling the devil's corkscrews of North America, was it possible, therefore, that Dinocochlea was actually the fossilised burrow of some still-undiscovered species of prehistoric rodent? Alternatively, bearing in mind that it was uncovered near to a quarry famous for the quantity of Iguanodon and other giant reptilian fossils discovered there, could it be a dinosaur coprolite (fossilised faecal deposit)? Once again, however, its gargantuan size (even for a coprolite of dinosaur origin!) and also its spiralled shape's very precise, regular form argued against this, as did the fact that there was no partially-digested organic material associated with it, which is normally the case with preserved coprolites. So what could this very curious, anomalous object be?

Dinocochlea, 1922 newspaper image (public domain)

In June 2011, palaeontologist Dr Paul Taylor from London's Natural History Museum (where Dinocochlea had been deposited following its discovery) officially presented a new and very plausible explanation.

In a paper published by the Proceedings of the Geologists' Association, he proposed that it had indeed originated as a corkscrew-shaped burrow, but a horizontal one rather than the vertically-oriented devil's corkscrews, and had not been created by any rodent but instead by a fossil species of capitellid polychaete worm known as a threadworm. Yet as these were only a few millimetres in diameter, how could so tiny a creature have produced such a monstrously huge trace fossil as Dinocochlea?

Dinocochlea life-sized model and Dr Paul Taylor of London's NHM (public domain)

Having examined cross-section specimens of it, which revealed that they were filled with concentric bands of sediment resembling the growth rings of tree trunks, Dr Taylor suggested that although initially very small, this worm burrow had acted as a nucleus for concretion growth (which is characterised by the presence of such rings or bands internally).

That is, the space originally created by the burrow would induce the movement into it of surrounding mineral cements, which would themselves then leave behind a space that would in turn induce the movement into it of more surrounding cements, and so on, until eventually, if conditions for its preservation were just right, what began as a tiny thin worm burrow would ultimately become enormously enlarged, yielding the very dramatic pseudo-gastropod, mega-burrow trace fossil that we know today as Dinocochlea.

An absolutely delightful cartoon version of Ceratogaulus (© Ursulav/deviantart)

From horned marmots and burrow-digging beavers to devil's corkscrews and terrible snails-that-weren't, it is evident that however distant our planet's past may be, it still possesses the power to perplex, surprise, inform, and fascinate us in a myriad of different ways.

The very attractive front cover of the How and Why Wonder Book of Prehistoric Mammals (© John Hull/Transworld)