Friday 25 April 2014

Blind Lizard

Image: Brown, Rafe
Here's an opportunity to impress your friends with your astonishing knowledge of a creature no-one has ever heard of! You could even start a rumour that its salivary glands hold the cure to wrinkled skin disease but the skincare-industrial complex keeps it under wraps. Who's to know?

Blind Lizards are yet another strange family of blind, limbless reptiles who burrow through the earth with their thick, bony skulls and feed on whatever insects and such they find down there. Just like that other peculiarity, the amphisbaenians.

This time there are a mere 20 or so species, but more are found now and then because "underground" is a really good hiding place. All species come from Southeast Asia except for one, ONE which is all the way over in Mexico.

More unusual for a legless lizard is the fact they have legs! Sort of. The males retain a pair of vestigial, hind flaps which they use to hold on to the female while mating. These are the sacrifices us fellas make for our ladyfolk. It's also why the Blind Lizard family is called Dibamidae, which means "two legs". So it is that a legless lizard is named after its legs. Not for the first time, either.

Image: J Holden/FFI
The evolutionary position of Blind Lizards has always been a source of debate. It's difficult when you have so many blind, legless reptiles burrowing underground! Are they blind and legless because they all evolved from something that was blind and legless? Or is it because that's just a really great way of living underground? Even amphibians like the caecilian have cottoned on to it. And no-one says Arctic foxes, snowshoe hares, snowy owls and snow leopards are white because they all evolved from a white, snow animal!

For a while it was thought that at least snakes (sometimes shiny and blind but always legless!), amphisbaenians (wrinkly, blind and legless!) and Blind Lizards were all closely related.

These days it looks like Blind Lizards, along with gekkotans, are a sister to all other Squamates (lizards and snakes).

This means there was a lizard which split into two groups. One of those groups split again into a bunch that began burrowing and became modern Blind Lizards, and another which became all the gekkotans. And as we know, some of those gekkotans became geckos with their fancy, sticky feet, while others went ahead and lost their legs!

The other leggy lizards that became neither Blind Lizards nor gekkotans evolved into all the other lizards we have today. But some of them lost their legs and became snakes, and then it happened again for amphisbaenians! And then it happened over and over and over again to a whole host of other lizards.

Long story short, lizards have always been rather lukewarm about their legs and are keen to drop them at the earliest opportunity.


Crunchy said...

That first picture almost makes a lizard pretzel!

Joseph JG said...

Haha! Someone needs to tell them that mimicking food doesn't work too well!

TexWisGirl said...

they look like washing machine hoses. :)

Joseph JG said...

Yeah! Lovely and shiny but still scaly. I bet they feel really nice!

Porakiya said...

man are lizards fickle about legs. Next thing you know, we'll be having legless iguanas and komodo dragons slithering about

Joseph JG said...

They just don't know a good thing when there's four of them sticking out of their body.

Legless Komodo Dragons, though... now that's something I'd love/hate to see!

BK said...

Off all the legless non-snake lizards, Lialis is the most snakelike. Hunts big prey, lures prey with tail, specially hinged jaws.

Joseph JG said...

Yup! They found a lizard way of doing almost everything a snake does.