New World's Smallest Vertebrate

[livius drusus]

His name is stout infantfish (http://news.bbc.co.uk/2/hi/science/nature/3920183.stm). He's no more than 2 months old, enjoys short swims along the Great Barrier Reef and measures up to a hefty 7 millimeters. On a species level, he's a great catch:

Its tiny frame is matched by its short lifespan, which is thought to be a mere two months. This quick turnover might actually work in the fish's favour, allowing it to keep up with a world that is changing fast.

"It's interesting that these animals experience several generations a year," said Dr Watson. "This suggests they could evolve quickly as well.

"They live in a specialised habitat that could be threatened by global warming or human development, but they may have the ability to evolve as fast as their environment changes."

How you doin'?http://newsimg.bbc.co.uk/media/images/40418000/gif/_40418773_stout_infantfish_inf203.gif

[Roland98]

Aww, ain't it cute!

I'm still a bit partial to this guy. (http://www.science.psu.edu/journal/Fall2002/Lizard-FA02.htm)

The world's smallest lizard has been discovered on a tiny Caribbean island off the coast of the Dominican Republic. The newly discovered species not only ranks as the smallest lizard, but it also is the smallest of all 23,000 species of reptiles, birds, and mammals, according to a paper to be published in the December issue of the Caribbean Journal of Science by Blair Hedges, an evolutionary biologist at Penn State, and Richard Thomas, a biologist at the University of Puerto Rico.

So small it can curl up on a dime or stretch out on a quarter, a typical adult of the species, whose scientific name is "Sphaerodactylus ariasae," is only about 16 millimeters long, or about three quarters of an inch, from the tip of the snout to the base of the tail. It shares the title of "smallest" with another lizard species named Sphaerodactylus parthenopion, discovered in 1965 in the British Virgin Islands.

http://www.science.psu.edu/alert/photos/miscphotos/mlizdime.jpg


Anyone wanna guess why lizards, fish etc. can be this tiny, but mammals can't?

[livius drusus]

OMG he's sooooo cute! Can I have one? Pleeeaaaase?

Oh, erm, right. Why can they be so tiny but mammals can't... Um... Cold blood? Small brains? Much like mine right now?

[Roland98]

Cold blood. Mammals generate their own body heat, and as you get smaller and smaller in size, you end up with a large surface area in proportion to your volume. Therefore, you're losing a lot of heat to the environment. Animals that are exothermic don't have to worry about this as much, as their body temperature is regulated by the environment anyway. SA:V ratios really limit a lot in biology; it's an interesting little quirk of physics and was my favorite part about teaching zoology.

So there's your little factoid for the day. ;)

[livius drusus]

That was a delightful fact nugget; thank you, Roland. :yup:



So, um, now can I have one of those micro-lizards?

[Dingfod]

Are those full-grown vertibrates? I've seen baby hornytoads that could fit on a quarter, they're so darn cute when they're little like that.
http://geoinfo.nmt.edu/staff/wilks/lizards/lizard_images/images/BabyHorned06_jpg.jpg


Warren

[Roland98]

Yep, those are full-grown.

And liv, you get one when I do. :)

[JoeP]

Cold blood. Mammals generate their own body heat, and as you get smaller and smaller in size, you end up with a large surface area in proportion to your volume. Therefore, you're losing a lot of heat to the environment. Animals that are exothermic don't have to worry about this as much, as their body temperature is regulated by the environment anyway. SA:V ratios really limit a lot in biology; it's an interesting little quirk of physics and was my favorite part about teaching zoology.

So there's your little factoid for the day. ;)

And the smallest mammals have to eat pretty much continuously to generate this heat. Pygmy shrews eat twice their body weight (OK, that's not much) a day and cannot go for more than a few hours (like sleeping overnight) without food.

Hey, can't let Science Nerd have all the factoids.

[viscousmemories]

And the smallest mammals have to eat pretty much continuously to generate this heat. Pygmy shrews eat twice their body weight (OK, that's not much) a day and cannot go for more than a few hours (like sleeping overnight) without food.
Sounds pretty much like me.