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Tetrapod Zoology

Tetrapod Zoology


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The carcass of a large, modern-day marine reptile!

The views expressed are those of the author and are not necessarily those of Scientific American.


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Having just covered Mesozoic marine reptiles, and seeing as I can’t find the time to finish anything more substantial, it seems like a good time to use these wonderful images, passed to me by a correspondent. They clearly show the carcass of a freshly deceased, modern-day marine reptile of Mesozoic style. For those in the know, the carcass has a real dolichorhynchopine polycotylid look about it.

Amazing stuff. Good to see that some marine reptiles have evolved a rather novel way to deal with the problems of discharging waste and procreating (do you know what I’m getting at? Say so in the comments). And – - scaly skin? Thanks to Bruce Schumacher.

In other news, lots of seabirds to come real soon. Just have to finish this Aquatic Ape Hypothesis article (and a bunch of other stuff) first.

Darren Naish About the Author: Darren Naish is a science writer, technical editor and palaeozoologist (affiliated with the University of Southampton, UK). He mostly works on Cretaceous dinosaurs and pterosaurs but has an avid interest in all things tetrapod. His publications can be downloaded at darrennaish.wordpress.com. He has been blogging at Tetrapod Zoology since 2006. Check out the Tet Zoo podcast at tetzoo.com! Follow on Twitter @TetZoo.

The views expressed are those of the author and are not necessarily those of Scientific American.





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  1. 1. Panimerus 7:00 am 03/8/2012

    There are many other marine organisms that have blind guts; excreting waste and such either through the skin or through the mouth. This surely must be convergent evolution at work.

    Link to this
  2. 2. NoniMausa 7:05 am 03/8/2012

    I would have said Inia geoffrensis, right after saying, more emphatically and with no chance of contradiction, “Oh, you poor thing!”

    And yes, the creature is a definite descendant of ancient marine animals — as are we all…

    Noni

    Link to this
  3. 3. Sordes 7:27 am 03/8/2012

    The scales are really nice…
    I have also some doubts the fragile teeth would be strong enough to hold the full weight of the body.

    Link to this
  4. 4. Cameron McCormick 7:36 am 03/8/2012

    No creationist repostings yet according to Tineye.

    Link to this
  5. 5. Dartian 7:38 am 03/8/2012

    Just have to finish this Aquatic Ape Hypothesis article

    Surely you do realise, don’t you, that such an article might invite commentary from the Wackaloon Brigade?

    Link to this
  6. 6. naishd 7:39 am 03/8/2012

    Dartian – I’m counting on it :)

    Darren

    Link to this
  7. 7. llewelly 9:35 am 03/8/2012

    hm, interesting, er, thing.

    Although I can’t shake the feeling that I’ve seen the photos before.

    Link to this
  8. 8. llewelly 9:41 am 03/8/2012

    by the way, a truly efficient predator would simply convert mass directly to energy and have no need of dispensing with waste.

    Link to this
  9. 9. Yodelling Cyclist 9:48 am 03/8/2012

    A nuclear powered plesiosaur? Hmmm, I sense a so-bad-it’s-good movie plot there…

    Link to this
  10. 10. naishd 9:54 am 03/8/2012

    As amusing as it all is (seriously, thanks everyone – smiley icon goes here), does anyone know anything about the history or background of this, err, individual? Not that I’ve done >any< research or investigation whatsoever, you understand.

    Darren

    Link to this
  11. 11. Heteromeles 10:00 am 03/8/2012

    Well, the absence of an anus clearly says that the animal is a coelenterate of a new phylum, and a truly spectacular example of convergent evolution. It’s amazing that its calcified tentacles so closely resemble teeth, and the jaw looks calcified as well. This suggests it’s closer to Cnidarians than to Ctenophorans. Perhaps it has nematocysts on those “dento-tentacles” giving it a venomous bite.

    I’m wondering whether it was a colonial organism or not. Is that tongue-analog a semi-separate organism, or is it just a developing bud that will separate off in due course, like a medusa? Inquiring minds want to know.

    Possibly it even has cilia, and those scales are structures evolved to direct the water flow like miniature jets, allowing it to swim in any direction without moving its flippers. It would be the biological equivalent of the “fan cloth” proposed by some futurists (http://www.orionsarm.com/eg-article/4a5f16c93e2ad)

    Fascinating. Too bad we don’t get to dissect it or even to get a genetic sample. We could learn so much from it. Most of the new animal phyla people have found are obscure little critters. Finding a big specimen like this tells us how little we really know about life in Earth’s oceans.

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  12. 12. Valerio Peverelli 10:37 am 03/8/2012

    I am surprised that none of the commentators have noticed the clearly visible wounds inflicted by a Ropen to this exemplary.

    New Guinea or Old Guinea?

    Ropen love both guineas.

    Valerio

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  13. 13. Yodelling Cyclist 11:36 am 03/8/2012

    Shame on you Valerio, clearly gorgonopsid wounds.

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  14. 14. Chris Mullens 11:53 am 03/8/2012

    Just dropped it into Google Images to search for similar images, and this one takes you right to the online portfolio of Julian Johnson-Mortimer (who digitally models assorted creatures) at http://www.johnson-mortimer.co.uk/galleries.html

    Fun stuff to look through, for sure, this one is in the third row down, another couple of images of it afterward.

    Link to this
  15. 15. naishd 11:57 am 03/8/2012

    On facebook, Lorenzo Rossi referred to it as Julianosaurus mortimeri, which kinda confused me. I suppose he meant Johnsonosaurus mortimeri. Some people say that a sagittal crest should be obvious/more obvious. Maybe, but there’s always ontogeny.

    Darren

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  16. 16. naishd 11:58 am 03/8/2012

    Ok, forget what I said. Missed the fact that Mortimer’s full name is Julian Johnson-Mortimer, duh.

    Darren

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  17. 17. Yodelling Cyclist 1:45 pm 03/8/2012

    Aah, just re re-read comments #5&#6. Excellent, I shall get beer and popcorn, then watch the comments thread.

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  18. 18. naishd 2:05 pm 03/8/2012

    I should add that the article was for BBC Focus magazine, not Tet Zoo. But I’ll see what I can do…

    Darren

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  19. 19. llewelly 10:27 pm 03/8/2012

    If aquatic apes are not real, how did monkeys get to South America?

    Link to this
  20. 20. Heteromeles 12:06 am 03/9/2012

    @Lewelly: On the floating forests that established the Amazon…

    Link to this
  21. 21. BK505 12:46 am 03/9/2012

    Does anyone but me notice the similarity of the flipper being held in the top photo to the shadowy underwater photo of the flipper allegedly to belonging to Nessie?

    Link to this
  22. 22. Jerzy New 4:11 am 03/9/2012

    April comes in early March? Yet another scientific proof of global warming.

    Link to this
  23. 23. David Marjanović 9:35 am 03/9/2012

    A nuclear powered plesiosaur? Hmmm, I sense a so-bad-it’s-good movie plot there…

    Yes yes yes yes yesssssssssss!!!!!

    And – – scaly skin?

    First you tell us it’s a reptile four times, and then you act surprised? Ceterum censeo Reptilia esse nomen delendum.

    Actually, not that I’d expect anything like this arrangement and shape of scales, but is any sauropterygian skin known in enough detail to rule mosasaur-style scales out?

    April comes in early March? Yet another scientific proof of global warming.

    Thread won. :-)

    Link to this
  24. 24. llewelly 10:15 am 03/9/2012

    Oh, that reminds me of a question I forgot to ask last time the floating islands hypothesis came up around here.
    Are there lineages of plants and insects which appear to have made the crossing at about the same time the ancestors of new world primates did? Heteromeles seems to think so, and as far as I can tell he’s not alone – so what are some examples?

    Link to this
  25. 25. ttheobald 10:30 am 03/9/2012

    I’d be really interested in knowing how these images were produced. That’s pretty good work.

    T

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  26. 26. Heteromeles 10:46 am 03/9/2012

    @llewelly: what counts as “at the same time?” Million years, plus or minus?

    Link to this
  27. 27. llewelly 11:07 am 03/9/2012

    Heteromeles:
    “@llewelly: what counts as “at the same time?” Million years, plus or minus?”

    Good question – I had thought the crossing of the ancestors of new world primates was not known to that precision – it seems me a range, usually 50 million to 75 million years ago, is used.

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  28. 28. Heteromeles 2:28 pm 03/9/2012

    Okay, so “at the same time” on a Tertiary scale means “plus or minus 12.5 million years, approximately.” That’s a lot of room for stuff to happen, IMHO.

    Link to this
  29. 29. llewelly 6:34 pm 03/9/2012

    Heteromeles : “Okay, so “at the same time” on a Tertiary scale means “plus or minus 12.5 million years, approximately.””

    If you can give me a narrower range for the migration of the ancestors of new world monkeys to S. America, please do.

    If not, I’ll do some looking around when I get home.

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  30. 30. BrianL 4:01 am 03/10/2012

    I think you can narrow that time gap down quite a bit. The idea of 75 million year old crown group primates (let alone anthropoids!) is preposterous, IMO. A middle Eocene- early Oligocene timeframe seems much more realistic.

    Reminds me of all those awful molecular hypotheses that want to explain avian biogeography with vicariance rather than dispersal and date the divergence of birds like acanthisittids and strigopids back to 80 million years because the idea of birds reaching isolated landmasses by flight is apparently unrealistic, despite enormous evidence to the contrary.

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  31. 31. John Scanlon FCD 5:04 am 03/10/2012

    I was going to say the resolution is insufficient to rule out a squamate-like transverse vent, but in the bigger version on the artist’s website you can actually make out a longitudinal, croc-like one.
    Possibly not a coelenterate then.

    Link to this
  32. 32. Hai~Ren 8:48 am 03/10/2012

    For a moment, I thought someone had some silly fun with a CM Studio Pliosaur model (http://cmstudio.com/pliosaur.html) (actually more polycotylid than pliosaurid).

    Link to this
  33. 33. Heteromeles 8:54 pm 03/10/2012

    Hi John,

    You’ve got better eyes than I do. For anyone else who wants to see whether the beasty is R-rated rather than G, the larger picture is here.

    Another silly conjecture, shot down by a thorough artist. Drat.

    Link to this
  34. 34. Heteromeles 11:02 pm 03/10/2012

    According to Poux et al (2006), caviomorph crossed from Africa to South America around 45-36 mya, and platyrrhine primates made the crossing 37-16 mya (with error bars on both sides of both estimates). These estimates are based on molecular clocks, and the fossil history of the modern platyrrhines starts quite a bit later.

    So it’s possible that a rodent and a primate shared the raft over, but it’s also possible they island hopped at quite different times.

    Poux, C., Chevret, P., Huchon, D., De Jong, W. W., Douzery, E. J. P. (2006). “Arrival and Diversification of Caviomorph Rodents and Platyrrhine Primates in South America”. Systems Biology 55 (2): 228–244. (www.tau.ac.il/%7Ehuchond/SB2006.pdf)

    Link to this
  35. 35. llewelly 11:47 pm 03/10/2012

    Thank you, Heteromeles.

    Link to this
  36. 36. Jerzy New 4:24 am 03/12/2012

    You guys say that rodents and monkeys got to South America by riding on a plesiosaur? Wow!

    Link to this
  37. 37. Dartian 7:18 am 03/12/2012

    llewelly:
    Are there lineages of plants and insects which appear to have made the crossing at about the same time the ancestors of new world primates did? Heteromeles seems to think so, and as far as I can tell he’s not alone – so what are some examples?

    Amphisbaenians. Molecular data suggest that they crossed the Atlantic from Africa to South America and to the West Indies in the Eocene, ca. 40 MYA. It’s even possible that two different amhisbaenian lineages made the crossing at roughly the same time (Vidal et al., 2008).

    Heteromeles:
    Systems Biology

    Systematic Biology.

    Reference:
    Vidal, N., Azvolinsky, A., Cruaud, C. & Hedges, S.B. 2008. Origin of tropical American burrowing reptiles by transatlantic rafting. Biology Letters 4, 115-118.

    Link to this
  38. 38. Dartian 7:37 am 03/12/2012

    I might add that the list of extant, terrestrial, flightless tetrapod taxa that dispersed successfully from Africa to the Americas in the Paleogene seems to be very short indeed. At least AFAIK, it only includes the platyrrhines, caviomorphs, and 1-2 lineages of amphisbaenians. (Later, in the Neogene, some gecko and skink taxa made the crossing too.)

    Link to this
  39. 39. Jerzy New 8:33 am 03/12/2012

    And Crocodylus crocodiles, as discussed before.

    Are there any extinct terrestrial, flightless tetrapod lineages which we presume crossed oceans?

    Link to this
  40. 40. Dartian 9:00 am 03/12/2012

    Jerzy:
    And Crocodylus crocodiles, as discussed before.

    Crocodiles hardly qualify as ‘terrestrial’, though (at least not the extant crocodyliforms).

    Are there any extinct terrestrial, flightless tetrapod lineages which we presume crossed oceans?

    If we restrict that question to mammals and to crossing the Atlantic, then there are none that I can think of. Except perhaps xenarthrans – if (and that’s a pretty big ‘if’) Eurotamandua really is related to the Neotropical anteaters.

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  41. 41. naishd 9:12 am 03/12/2012

    Trans-oceanic dispersal has to be invoked to explain the distribution of various snake and lizard lineages (both sphaerodactylid and phyllodactylid gekkotans, for example, seem to have crossed the Atlantic from Afro-Arabia to the Neotropics), plus (while not trans-ocean), overwater dispersal has been invoked many times to explain distribution of, for example, leptodactyliform frogs around the Caribbean and Central and north-eastern South America, tortoises on oceanic island groups, carnivorans and primates (and even bush-pigs and recently extinct hippos) on Madagascar… I suppose I should write about these cases in depth at some time.

    Darren

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  42. 42. naishd 9:19 am 03/12/2012

    Ok, I wasn’t paying attention, didn’t realise that Jerzy specifically asked about “extinct” groups, sorry.

    I would say that rarely is enough known about the biogeography of fossil lineages for trans-oceanic dispersal to be reliably inferred. Even for groups with crazy, ‘out-of-place’ occurrences (e.g., alleged horned dinosaurs on Australia), people have tended to invoke the use of former terrestrial connections.

    Darren

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  43. 43. John Scanlon FCD 11:02 am 03/12/2012

    “Are there any extinct terrestrial, flightless tetrapod lineages which we presume crossed oceans?”

    Mekosuchin mekosuchine crocodylids, as ancestors of M. inexpectatus and Volia and possibly the New Zealand croc, if it was also one of those guys. Depending on how Volia actually fits in (is Mekosuchus monophyletic?), that could just be a single trans-Tasman event. Not the biggest ocean, but too far for terrestrial mammals.

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  44. 44. David Marjanović 11:59 am 03/12/2012

    According to Poux et al (2006), caviomorph crossed from Africa to South America around 45-36 mya, and platyrrhine primates made the crossing 37-16 mya (with error bars on both sides of both estimates). These estimates are based on molecular clocks, and the fossil history of the modern platyrrhines starts quite a bit later.

    What, 16 Ma ago? I forgot its name, but the oldest known platyrrhine (a rather terrestrial animal, and, yes, from South America) is from the Oligocene.

    that could just be a single trans-Tasman event

    Though not just a single transoceanic dispersal; it has never been possible to walk between NZ and Fiji, or anywhere and Fiji.

    The question is exactly how terrestrial the mekosuchines were – assuming all mekosuchines were equally terrestrial, which probably wasn’t the case.

    Link to this
  45. 45. Dartian 1:22 pm 03/12/2012

    David:
    I forgot its name

    Branisella boliviana.

    Link to this
  46. 46. Jerzy New 3:11 pm 03/12/2012

    What about those horned tortoises on Pacific islands? Were they terrestrial?

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  47. 47. Christopher Taylor 7:53 pm 03/12/2012

    What about those horned tortoises on Pacific islands? Were they terrestrial?

    I believe they were. Mind you, aren’t even terrestrial tortoises supposed to be remarkably buoyant?

    Link to this
  48. 48. naishd 8:03 pm 03/12/2012

    Meiolaniids – the ‘horned tortoises’ – almost definitely originated in the Mesozoic. In fact recent phylogenies exclude them from the testudine crown, so they presumably originated in the Jurassic. Much of their distribution may therefore be explained by vicariance, not dispersal. However, in connection with what Chris said (comment 47), yes, big testudines are known to be extremely good at overwater dispersal – in 2004 an Aldabran giant tortoise was washed up on the east coast of Africa, having travelled 740 km. Some photos show (live) giant tortoises that were at sea for so long that their lower extremities became covered in barnacles.

    Darren

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  49. 49. Dartian 7:24 am 03/13/2012

    Darren:
    Some photos show (live) giant tortoises that were at sea for so long that their lower extremities became covered in barnacles.

    Tortoises? Correct me if I’m wrong, but there’s just that one barnacle-covered giant tortoise individual on record, right? (Judging by the size of those barnacles, by the way, the tortoise had spent 6-7 weeks in the sea.) Even so, this is a most remarkable incident. The full reference, incidentally, is:

    Gerlach, J., Muir, C. & Richmond, M.D. 2006. The first substantiated case of trans-oceanic tortoise dispersal. Journal of Natural History 40, 2403-2408.

    Link to this
  50. 50. David Marjanović 5:34 pm 03/13/2012

    Barnacles on a living tortoise? Wow.

    Branisella boliviana.

    Ah, yes, thanks.

    Link to this
  51. 51. Crocodopolis.net 2:33 pm 03/26/2012

    This is clearly a fake and perpetrated by an amateur. At least one aspect of the morphology clearly gives it away. Can you spot it?

    Link to this

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