Goblin Sharks are Giants

Goblin Sharks (Mitsukurina owstoni) may be among the largest of cartilaginous fishes. While generally credited with a maximum total length of 3.8 meters (12’6″), one specimen appears to have exceeded that by far.

In July 2000, an enormous shark was accidentally captured in the northern Gulf of Mexico after being entangled in a line attached to a crab trap (Parsons et al. 2002). Only the jaws of the shark were kept by the fishers (Parsons et al. 2002) and it is unknown why they weren’t examined by the authors. Considering the fishers took the time to dissect the shark (Parsons et al. 2002) I’m puzzled that no measurements were provided. The above photo, while clearly demonstrating Goblin Shark morphology and giving the impression of great size, unfortunately lacks any landmarks which can establish scale. Fortunately, a second photograph focusing on the head was taken and it proved surprisingly informative about the Gulf shark’s size.

The rope proved to be the key. With a known diameter of 2.06 cm (0.8″) Parsons et al. were able to measure a snout to eye distance of 62.9 cm (2’1″). Scaling up from the previously largest known specimen yielded a total length of 5.4 m (17’9″) for the Gulf shark (Parsons et al. 2002). The authors suspected the figure may have been an underestimate as snouts become proportionally shorter with increased total length and so used an exponential regression to calculate a total length of 6.17 m (20’3″). I strongly suspect the latter figure is closest to reality. I calculated the above photograph shows about 3.5 meters (11’6″) of shark despite most of the tail being out of frame. The aforementioned 3.84 m specimen appears to have a proportionally much longer snout, lending credence to the notion that 5.4 m is an underestimate. Of course it would be nice if those jaws showed up – or better yet, a similarly-sized specimen – but the case for gargantuan Goblin Sharks seems compelling.

Is the Gulf shark some one-off freak? I suspect not. The Gulf shark was the first specimen ever recorded from the Atlantic coast of North America (Parsons et al. 2002) and is still apparently the only known (Castro 2011). Adult Goblin sharks have only been “occasionally reported” presumably due to their deep water habitat (Castro 2011) and this list suggests they are very occasional indeed. With such a small sample size, a lack of Gulf shark-sized individuals could just be a statistical quirk. Perhaps there is bias towards the capture of smaller individuals as a ~6 m individual (perhaps approaching a tonne in weight) could be prohibitively large for most vessels to catch, let alone haul on board and preserve. Here’s to hoping that a monstrous specimen scares the hell out of an ROV crew someday!

Goblin Sharks may be giants, but they are far from alone in the lightless depths and far from being the largest. More soon.

References:

Castro, J. (2011) The Sharks of North America. Oxford University Press.

Parsons, G. R., et al. (2002) First record of the goblin shark Mitsukurina owstoni, Jordan (Family Mitsukurinidae) in the Gulf of Mexico. Southeastern Naturalist 1(2), 189-192.

Stupendemys

Stupendemys is just, well, stupendous. Even after encountering a ceiling-suspended specimen at the American Museum of Natural History, the ground-level replica at the Harvard Museum of Natural History came as a shock. Of course, part of this shock was due to having no idea there was even a replica at the museum, wandering off to see ‘Plasterosaurus’, and then coming face to scutes with a hunk of shell about the size of a dining room table.

The AMNH and HMNH carapaces appear to be replicas of MCZ(P) 4376, which has a strait carapace length of 2.18 meters (~7’2″) (Wood 1976). Despite almost being large enough to inhabit, this shell appears to be on the small side for Stupendemys geographicus. Wood estimated another specimen to have an SCL of 2.30 m (7’7″), Bocquentin and Melo (2006) mentioned a 3.18 m (10’5) SCL specimen, and Scheyer & Sanchez-Villagra (2007) sampled two, one which was ~2-3 m (~6’7″ to 9’10”) in SCL and another which was 3.30 m (10’10”) with a carapace width of 2.18 meters. It’s almost beyond belief that the turtle body plan would still be functional into the multi-ton range – I’m especially curious how egg laying was accomplished – but I suppose stranger things have happened.

Stupendemys is remarkable for reasons other than being about the size of a compact car. At the anterior end of the carapace is a thickened and upturned ‘collar’, apparently unique among turtles (Wood 1976). Wood examined two S. geographicus specimens, and as one (pictured above) had a more developed collar, he speculated that it may be a secondary sexual characteristic. The other Stupendemys, S. souzai, has a collar which is developed to a similar degree but is vertical rather than curled back (Bocquentin & Melo 2006). Bocquentin & Melo speculated that S. souzai would not have been able to inhabit areas with swift currents and would have been restricted to swamps and small streams; the authors also curiously imply that S. geographicus was marine due to its association with the turtle Bairdemys. Whether or not S. geographicus is marine still appears to be an open issue (Sánchez-Villagra & Scheyer 2010); I feel obliged to point out that ostensibly “freshwater” turtles wandering around in marine settings are not uncommon… but that’s a story for another day.

Underneath the collar is a deep median notch which, owing to comparisons with the distantly related Platysternon, Wood took as evidence that Stupendemys had a similarly large, non-retractile and heavily plated head. Platysternon doesn’t have exclusive ownership of similarly deep notches (also present in some snapping turtles, musk turtles, seaturtles, et cetera) and among the much closer relatives of Stupendemys (also members of Podocnemididae) Erymnochelys and Peltocephalus have big heads and prominent but comparatively shallow notches. I see no reason to think that Stupendemys had a radically different approach to neck retraction than other side-necked turtles as suggested by Wood, although of course further study of the neck vertebrae and (when found) the skull will be needed before making any conclusions.

Despite having no known skull (the above is enlarged Caninemys material), this didn’t stop authors from speculating on the diet of Stupendemys. Wood postulated it was largely or entirely herbivorous due to its size, as he was under the curious impression that the largest living turtles (terrestrial and marine) were herbivorous – was the famous jellyfish-heavy diet of Leatherbacks not known back then? Bocquentin & Melo curiously stated that Stupendemys had the appearance of a “predaceous bottom-dweller” but didn’t explain how they arrived at that conclusion. My own nearly-baseless speculation is that Stupendemys was a generalized omnivore – considering how much growth they had to accomplish, it seems unlikely for them to refuse anything. Then again, Leatherbacks attain huge sizes on jellyfish, so Stupendemys could very well have been up to something completely ridiculous.

References:

Bocquentin, J. & Melo, J. (2006) Stupendemys souzai sp. nov. (Pleurodira, Podocnemididae) from the Miocene-Pliocene of the Solimões Formation, Brazil. Revista Brasileira de Paleontologia 9(2), 187-192. Available.

Sánchez-Villagra, M. R. & Scheyer, T. M. (2010) Fossil Turtles from the Northern Neotropics: The Uromaco Sequence Fauna and Finds from Other Localities in Venezuela and Colombia IN: Sánchez-Villagra, M. R. et al. (eds.) Uromaco and Venezuelan Paleontology. Indiana University Press.

Scheyer, T. M. & Sánchez-Villagra, M. R. (2007) Carapace bone histology in the giant pleurodiran turtle Stupendemys geographicus: Phylogeny and function. Acta Palaeontologica Polonica 52(1), 137–154. Available.

Wood, R. C. (1976) Stupendemys geographicus, the world’s largest turtle. Breviora 436, 1-31. Available.

Ockham Debunked: Brunet’s Dæmoneojersianus and Cryptic Halichoerus-Cadborosaurus-Hypsignathus Hypersynonymy: A New Age of Reason

[E]ntia non sunt multiplicanda praeter necessitatem

– Ed L. Bousfield & Paul H. LeBlond, Pipefish or Pipe Dream?

Spatio-temporal quantum phenotype “type” manifestations of Dæmoneojersianus nomen-complex. Rightenover: Dæmoneojersianus brunetii sp. nov.; Down-Bottom: Cadborosaurus willsi (LeBlond & Bousfield 1995) Nomen Nudum; Leftmost: Hypsignathus monstrosus Species Inquirenda; Also Depicted: Halichoerus grypus Nomen Oblitum.

Through the sands of Time immemorial, Mankind have run afoul of Hippocephali even a child could distinguish from the familiar Equus. The close-minded Modern Linnaeusists brush “Halichoerus grypus” under the rug under the label “seal” and clumsily force “Hypsignathus monstrosus” into the pigeonhole “bats”. But how can species with the heads of horses be spread across entire distinct Orders of Mammalia? They cannot be. The Cult of Taxo-“nomists” haughtily look down upon LeBlond and Bousfield’s  “Cadborosaurus willsi” – that brave and noble classification which tragically fell upon deaf ears – and none but myself have the courage to describe Dæmoneojersianus brunetii (sp. nov. – this paper). It is clear these Phylo-infected “taxonomists” care more for making genetic “information” dance like a puppet on its strings at their whims upon gels than a True classification. Only I have the bravery and aptitude to classify Animalia, as I will heretofore demonstrate.

Analysis:

Holotype and Lectotype of Dæmoneojersianus brunetii. Diagnosis: Classic Hippocephalic condition; Limb pair I/II clearly distinguished; cranial appendages; neck flexibility characteristic of amphicoelous cervicals; trifurcate (fluke-like) caudal appendage.

Actual knowledge about a taxon is not contained within DNA. This knowledge derives from direct observation of morphology

– Malte C. Ebach, Marcelo R. de Carvalho, & Silvio S. Nihei, Saving our science from ourselves: the plight of biological classification.

Syntype of Dæmoneojersianus brunetii sp. nov. Diagnosis: Hippocephalic condition; cranial appendages; pseudo-ziphiid condition; Limb pair I/II fusion; manus reduced to digits II, III, & IV; flukes absent.

What these Skeptics and Debunkers trot out as “fossil” “evidence” is but a fool’s dream. How can bone turn to stone? No more so than a barnacle could transform into a bird! The objects known as fossils were carved by the Victorian Sentinelese to fool Sir Richard Owen into believing a “pre”-history; the Sentinelese now reign in the Earth’s Core, waiting for Humanity to grow weak and flabby from belief in “Evolution”, and then they will strike. For more on our would-be overlords and other wonders please consult Bühler’s Subterranea Victores et alia Mirabilia, of which I have the only copy extant.

[I]n animals that metamorphose, the basic types of larvae originated as adults of different lineages, i.e., larvae were transferred when, through hybridization, their genomes were acquired by distantly related animals.

– Donald I. Williamson, Caterpillars evolved from onychophorans by hybridogenesis

Syntypes of Dæmoneojersianus brunetii. Diagnosis: “Cadborosaurus” form ontology as follows: 5 humps, 5 loops, 4 loops, 1 hump, serpentine/crocodilian. Fluke structures and heads shared in both life-stages.

A procession of the damned.
By the damned, I mean the excluded.
We shall have a procession of data that Science has excluded.

– Charles Fort, The Book of The Damned

Paratype of Dæmoneojersianus “The Danish Sea-Monkey” type I/II transitional form. Diagnosis: Cranial appendage; Limb pair III fused into long “tail”; Hippocephaly mildly developed due to juvenile condition. 

How often have I said to you that when you have eliminated the impossible, whatever remains, however improbable, must be the truth?

Sherlock Holmes, The Sign of the Four

All I want is to know things. The black gulph of the infinite is before me

– H. Phillips Lovecraft, Letter to Frank Belknap Long (27 February 1931)

Discussion:

As incontrovertibly demonstrated in the Analysis above Dæmoneojersianus brunetii is composed of four distinct adult forms: 2 incorrectly described as a seal and a bat, another as a cryptid, and another unknown. For those of you for whom this analysis was somehow  not clear enough, I present this diagrammatic summary:

What is the Ultimate Species, that which for the whole process of Creation set in motion by our Space-Progenitors was for? Is it man with his enlarged forebrain, well-developed buttocks, and ability to travel to the moon? No, for Man is weak and easily overpowered by the lowliest female orangutan. Is it the bacteria – the Chaos infusorium of Linneaus – with their infinite adaptability and fast generations? No, for even Man will surely ever hold them at bay with His chemical concoctions. No, the ultimate species is so Ultimate for the recognition it does not get, except from those smartest of humans. It allows itself to be seen under certain guises, yet adopts others so probable only a fool could believe them. When it is too often seen, it transforms into another beast with no seeming connection. They can never be caught, or if they are seemingly so, leave but a shell for plodding Man to find and ponder over. It is only the wisest of us that can see them, see the patterns.  I am smarter than everyone, and no doubt myopic fools will assail my monolith of logic with their “Razor of Ockham” and their “Causality” – and it shall be their DOOM!

References:

Bousfield, E. L., & LeBlond, P. H. (2011) Pipefi sh or Pipe Dream? Journal of Scientifi c Exploration, Vol. 25, No. 4, p. 779–780, 2011 0892-3310/11

Ebach, M. C., et al. (2011) Saving our science from ourselves: the plight of biological classification Rev. Bras. entomol. vol.55 no.2 São Paulo June 2011 Epub June 17, 2011 Epub June 17, 2011 http://dx.doi.org/10.1590/S0085-56262011005000005

Williamson, D. I. (2009) Caterpillars evolved from onychophorans by hybridogenesis

Proc Natl Acad Sci U S A. 2009 November 24; 106(47): 19901–19905. Published online 2009 August 28. doi:  10.1073/pnas.0908357106

PMCID: PMC2785264