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In case you forget, softshell turtles are insanely weird

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


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I wanted to use this photo because it’s weird and interesting, not because I have anything particularly insightful to say about softshell turtles. The animal shown here is a Florida softshell Apalone ferox that I photographed in captivity earlier in 2011. Turtles of many kinds look odd when they adopt resting or basking poses; this softshell looks so odd that you could probably fool some people into thinking that it’s an alien or something. Anyway, A. ferox is a mid-sized softshell (carapace length 15-60 cm, with females being larger) from freshwater habitats of the southeastern USA. Individuals are occasionally found in brackish water and sometimes get swept out to sea. It likes to partially bury itself in soft mud and is said to be especially speedy at tunnelling and digging. It’s also pretty fast on land – there are videos on youtube of individuals moving at speed. Having mentioned videos, I love this one…

Florida softshell takes a dive, makes golf interesting

After I posted this video on facebook (back in May 2011), it occurred to me that the forelimbs of the featured animal are asymmetrical. But, no, it’s just that the animal doesn’t fully extend its right forelimb. It does seem to be missing its right eye, however.

One interesting bit of softshell trivia (of relevance to those especially interested in anatomical changes that occur during ontogeny): old males sometimes develop enlarged crushing platforms on the edges of the upper jaws (why males and not females? As mentioned above, females are larger). They might use these ‘platforms’ to crush molluscs. A. ferox is mostly carnivorous, eating everything from crustaceans and snails to frogs, fish and birds, but it might also eat plant material on occasion. And here’s another interesting photo of a Florida softshell, especially interesting if (like me) you’re into necks. The photo is by Johnskate17 and was taken from wikipedia.

For previous Tet Zoo articles on softshells, see…

And for other articles on other kinds of turtles, see…

More on turtles in 2012, and much else besides. Ichthyosaur Revolution and sexual selection in Mesozoic ornithodirans to come 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. Jurassosaurus 1:08 pm 12/31/2011

    That first photo is so weird. I assume the heat lamp must have had a red tinge to it. It makes it looks like the turtle had a really nasty sunburn.

    Link to this
  2. 2. Cameron McCormick 1:41 pm 12/31/2011

    carapace length 15-60 cm

    It’s at least 67.3 cm SCL. Meylan and Moler (2006) report a specimen with a “carapace length” of 73.6 cm and weight of 43.6 kg, but Ernst and Lovich (2009) regard it as “unsubstantiated”. Even if the species really does push 100 pounds, it is still quite modest compared to some other softshells.

    with females being larger
    MUCH larger – 67.3 cm vs. 32.4 cm max SCL, so probably at least 8x as massive.

    why males and not females?
    Females exhibit the allometry as well.

    Link to this
  3. 3. Cameron McCormick 1:49 pm 12/31/2011

    I can’t find a free version of Dalrymple (1977), so here’s the abstract. Ernst and Lovich (2009) state several times that the expanded crushing surface is present in “old individuals” without specifying a gender.

    Link to this
  4. 4. WarrenJB 8:48 am 01/1/2012

    “…this softshell looks so odd that you could probably fool some people into thinking that it’s an alien or something.”

    I’m calling it now. This’ll be one of the new bleurghosphere memes of 2012. “BIZARRE GENETIC EXPERIMENT DISCOVERED: Is this what killed the Montauk Monster?”

    Link to this
  5. 5. naishd 12:28 pm 01/1/2012

    Red colour: I assumed at the time that the animal really was reddish, but red-tinged lighting looks more likely. I’m trying to find out.

    Alleged dimorphism of ‘crushing platforms’: the idea that these are unique to males seems to come from Ernst & Barbour (1989): yes, they specifically state this on p. 103. Thanks (Cameron) for the correction.

    Have just spent substantial time today looking at matamata, snapping turtle and Chinese pond turtles.

    Ref – -

    Ernst, C. H. & Barbour, R. W. 1989. Turtles of the World. Smithsonian Institution Press, Washington, D. C. & London.

    Link to this
  6. 6. BilBy 2:29 pm 01/1/2012

    These guys can often be seen wandering across roads in Florida, and if they take a wrong turn they shuttle back and forth between the walls of low bridges trying desperately to get to water. When I rescue them, often they are dehydrated, exhausted and can barely snap, but they take off into the creek with and air of relief. Odd factoid based on limited sample size – Florida softshells feel lighter and less dense somehow than African Zambezi softshells – they always seems surprisingly hefty when picked up.

    Link to this
  7. 7. Mike from Ottawa 2:47 pm 01/1/2012

    Take a look at the rocks in the centre and right foreground and you can see they’re red-tinged just like the turtle, so it’s definitely the lighting.

    To me the oddest thing is that the turtle looks kind of like it’s melted onto the rocks.

    Link to this
  8. 8. Hai~Ren 3:48 am 01/2/2012

    Here in Singapore, the Chinese softshell turtle (Pelodiscus sinensis) is used for turtle soup. The Chinese softshell has also been released and introduced into many urban water bodies, due to escapes from farms and releases by well-meaning folks. We’ve got 2 (possibly 3) native species of softshell turtle, Asiatic (Amyda cartilaginea), Malayan (Dogania subplana), and maybe Asian giant (Pelochelys cantorii).

    Speaking of which, does anyone know if that pair of Yangtze giant softshell turtle (Rafetus swinhoei) at the Suzhou Zoo has managed to breed yet? Given that there are only 4 known living individuals (the other 2 being the famous turtle of Hoan Kiem Lake in Hanoi and another one in Dong Mo Lake, also in Vietnam), it’s really literally the last hope for the species.

    Link to this
  9. 9. vdinets 4:26 pm 01/2/2012

    Hai-Ren: As far as I know, all recently laid eggs were infertile. Apparently, the male is too old. The male in Dong Mo is young, but so far the Vietnamese refuse to consider sending it to China. The whole issue is extremely sensitive.

    Link to this
  10. 10. naishd 5:00 pm 01/2/2012

    I do mean to write about the Hoan Kiem turtles at some stage. At least three papers have been published since 2003 criticising the naming of R. leloii; it also seems that there are more R. swinhoei specimens in museum collections than thought until recently – most of them were misidentified as Pelochelys. And there’s the enigmatic P. taihuensis, named in 1984 for fossils and taxiderm specimens. Also seems to be a synonym of R. swinhoei. I wonder if it’s true that Rafetus is closer to Apalone than any other extant softshell – this is what some phylogenetic studies conclude.

    Darren

    Link to this
  11. 11. vdinets 10:02 pm 01/2/2012

    Darren: be sure to email me when you get to writing about it, I have a few interesting tidbits to share :-)

    Link to this
  12. 12. naishd 5:18 am 01/3/2012

    Ok, will do. Interesting.

    Darren

    Link to this
  13. 13. Owlmirror 4:28 pm 01/3/2012

    Tangential thought: There does not appear to be a paper titled “What, if anything, is a turtle?”

    Should there be?

    Link to this
  14. 14. naishd 4:48 am 01/4/2012

    Last night I happened to find my other photos of the very red softshell shown at the top. It is, after all, definitely the lighting that made it look red (easy to demonstrate, since a palm frond close to the turtle is red as well). Mystery solved.

    Darren

    Link to this
  15. 15. naishd 4:34 pm 01/4/2012

    For those interested, the photos concerned are now available on the Tet Zoo facebook page.

    Darren

    Link to this
  16. 16. eldri 4:19 pm 01/7/2012

    When I was a kid, I had one (a hatchling,) as a pet.
    Given a Choice it would bury itself in the Shallows and just snorkel for air—but if I put it in the big tank while I cleaned its home
    It would sometimes sit on the bottom of the tank with mouth agape and neck slightly extended; sometimes ‘inflated’ and deflated a bit
    —I always thought it was using capillaries inside the neck to extract oxygen from the water, to extend the time between swimming up for air.

    Are there reports of this?

    Link to this

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