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Must be some fundamental limit on the size of organs and tissues, to still function. Or, there are smaller reptiles and we just haven't 'seen' them yet! Who's l

Must be some fundamental limit on the size of organs and tissues, to still function. Or, there are smaller reptiles and we just haven't 'seen' them yet! Who's looking behind every blade of grass for an iguana after all. Insects win the 'smallest' title - the Fairy Wasp is 0.13mm

mojomark 6y ago
This comes up from time to time, but it's pertinent to the discussion (more so on larger scales, but the reverse holds true], so in case you haven't had the delight of reading [1]. 1. PDF download link: https://www.phys.ufl.edu/courses/phy3221/spring10/HaldaneRightSize.pdf https://www.phys.ufl.edu/courses/phy3221/spring10/HaldaneRig...
ralfd 6y ago
Maybe the limit is not function, but being competitive. Insects don’t have lungs and an open instead of closed circulatory system, with a tubular “heart” sloshing around hemolymph instead of blood. At this small size this should have advantages?
- pitspotter 6y ago
  Yes, and I was thinking about its eyes. The human eyeball has diameter roughly equal to the entire length of this lizard, making its volume 10,000X larger than the lizard's eyeball. OTOH, with a pupil that small, visual depth of field must be large. So perhaps the nano-chameleon doesn't need to do much in the way of focussing. Small wonder they took so long to discover :-p
  - pdpi 6y ago
    > OTOH, with a pupil that small, visual depth of field must be large. But the pupil is also small enough that diffraction is a major issue so their visual acuity is probably quite poor
    - pitspotter 6y ago
      Good point. So it can also 'get away with' having tiny retinas, since there's less information available to resolve.
itissid 6y ago
I was wondering the same thing. But as pointed out here[1]. There are some interesting points: Cell size is actually affected to genome size and cell size has a more complex relation to Physical Shapes and sizes: " As a result, species that are the same physical size but have different genome and cell sizes likely also differ in ways that significantly affect morphogenesis, growth, and adult morphology. Analysis of organismal size and size change thus becomes a consideration not simply of physical size, but also of a more elusive concept-biological size." Even within a species the variation is tremendous: "In some groups, miniaturization may have been achieved by cell size decrease (65). In others, extensive genome and cell size variation complicates tremendously even basic comparisons of body size among taxa." I remember seeing attenborough on TV how a species of frogs living in the cold areas just allow themselves to be frozen for long periods of time and then thaw back to life! [1] https://www.researchgate.net/profile/James_Hanken/publication/290469788_Miniaturization_of_Body_Size_Organismal_Consequences_and_Evolutionary_Significance/links/56f28c0f08ae4cb04b2647a0/Miniaturization-of-Body-Size-Organismal-Consequences-and-Evolutionary-Significance.pdf https://www.researchgate.net/profile/James_Hanken/publicatio...
cromka 6y ago
> Insects win the 'smallest' title - the Fairy Wasp is 0.13mm I find this photo mesmerizing. It's almost as if it was digitally rendered, or sculptured with metal: https://upload.wikimedia.org/wikipedia/commons/c/ca/Mymarilla_wollastoni.jpg https://upload.wikimedia.org/wikipedia/commons/c/ca/Mymarill...
kevin_thibedeau 6y ago
Plenty of reptiles hatch from an egg smaller than this and can fend for themselves. The only thing special is that the growth of these and other miniature chameleons ends at an abnormally small size.
- TylerE 6y ago
  Citation? Reptiles tend to have pretty large babies in comparison to their body size, actually. Babies are smaller, but not nearly THIS small. Most typical lizards are already several inches straight out of the egg.
  - JoeAltmaier 6y ago
    It occurs to me, that the eggs of this reptile are by necessity much smaller than the adult. Thus, the young are likely born somewhat smaller than the given record-breaking size.
    - TylerE 6y ago
      But read the post I'm replying to. Most reptiles are FAR larger the adults of this species even right out of the egg.

mojomark 6y ago

This comes up from time to time, but it's pertinent to the discussion (more so on larger scales, but the reverse holds true], so in case you haven't had the delight of reading [1]. 1. PDF download link: https://www.phys.ufl.edu/courses/phy3221/spring10/HaldaneRightSize.pdf https://www.phys.ufl.edu/courses/phy3221/spring10/HaldaneRig...

ralfd 6y ago

Maybe the limit is not function, but being competitive. Insects don’t have lungs and an open instead of closed circulatory system, with a tubular “heart” sloshing around hemolymph instead of blood. At this small size this should have advantages?

pitspotter 6y ago
Yes, and I was thinking about its eyes. The human eyeball has diameter roughly equal to the entire length of this lizard, making its volume 10,000X larger than the lizard's eyeball. OTOH, with a pupil that small, visual depth of field must be large. So perhaps the nano-chameleon doesn't need to do much in the way of focussing. Small wonder they took so long to discover :-p
- pdpi 6y ago
  > OTOH, with a pupil that small, visual depth of field must be large. But the pupil is also small enough that diffraction is a major issue so their visual acuity is probably quite poor
  - pitspotter 6y ago
    Good point. So it can also 'get away with' having tiny retinas, since there's less information available to resolve.

itissid 6y ago

I was wondering the same thing. But as pointed out here[1]. There are some interesting points: Cell size is actually affected to genome size and cell size has a more complex relation to Physical Shapes and sizes: " As a result, species that are the same physical size but have different genome and cell sizes likely also differ in ways that significantly affect morphogenesis, growth, and adult morphology. Analysis of organismal size and size change thus becomes a consideration not simply of physical size, but also of a more elusive concept-biological size." Even within a species the variation is tremendous: "In some groups, miniaturization may have been achieved by cell size decrease (65). In others, extensive genome and cell size variation complicates tremendously even basic comparisons of body size among taxa." I remember seeing attenborough on TV how a species of frogs living in the cold areas just allow themselves to be frozen for long periods of time and then thaw back to life! [1] https://www.researchgate.net/profile/James_Hanken/publication/290469788_Miniaturization_of_Body_Size_Organismal_Consequences_and_Evolutionary_Significance/links/56f28c0f08ae4cb04b2647a0/Miniaturization-of-Body-Size-Organismal-Consequences-and-Evolutionary-Significance.pdf https://www.researchgate.net/profile/James_Hanken/publicatio...

cromka 6y ago

> Insects win the 'smallest' title - the Fairy Wasp is 0.13mm I find this photo mesmerizing. It's almost as if it was digitally rendered, or sculptured with metal: https://upload.wikimedia.org/wikipedia/commons/c/ca/Mymarilla_wollastoni.jpg https://upload.wikimedia.org/wikipedia/commons/c/ca/Mymarill...

kevin_thibedeau 6y ago

Plenty of reptiles hatch from an egg smaller than this and can fend for themselves. The only thing special is that the growth of these and other miniature chameleons ends at an abnormally small size.

TylerE 6y ago
Citation? Reptiles tend to have pretty large babies in comparison to their body size, actually. Babies are smaller, but not nearly THIS small. Most typical lizards are already several inches straight out of the egg.
- JoeAltmaier 6y ago
  It occurs to me, that the eggs of this reptile are by necessity much smaller than the adult. Thus, the young are likely born somewhat smaller than the given record-breaking size.
  - TylerE 6y ago
    But read the post I'm replying to. Most reptiles are FAR larger the adults of this species even right out of the egg.