Some of Florida's aquatic salamanders

I've recently spent some effort searching for sirens (only have two front legs, which are large enough to be functional, and have obvious external gills) and amphiumas (have all four legs, but legs are tiny vestigial structures which are essentially non-functional, and have gill slits instead of obvious external gills), both of which are eel-like salamanders that spend most of their time in water and mud. Because of their habitat preferences, they aren't something I would likely see without going out of my way. They're also not the easiest to get natural looking photos of, unless you have an underwater camera, or a clear-sided container to photograph through. Not sure these are all that enjoyable to look at, but they sure were neat to find and see.

Greater Siren (Siren lacertina)
These babies can grow to over three feet in length, and get pretty bulky as well. They can filter small invertebrates from soft substrates, and they will opportunistically grab any larger organisms that will fit in their mouths.


baby and adult


Two-toed Amphiuma (Amphiuma means)
These toothy predators can reach a length of nearly four feet! They will sometimes sit with only their heads sticking out of the mud, waiting for prey to come close enough to grab, and other times will actively wander around in search of prey. They will eat any animal that they can hold on to and swallow, which includes a lot of things. They have all four legs, but they are tiny, and of course include two toes per foot.

Narrow-striped Dwarf Siren (Pseudobranchus axanthus axanthus)
Last and least, these sirens are tiny in comparison to the previous two species mentioned. These sirens eat tiny aquatic invertebrates.


heidi said...

Delicious! I've never encountered such slimy elegance in the wild, but Rio Grande Sirens are frustrating in captivity - very cool to feed, but not so cool when they try to tear each other to bits. Thanks for posting the pics for scale!

Kelly said...

I've read that lesser sirens can be territorial, but I didn't know what they would do in captivity. Did they actually injure each other?
Congrats to you and Matt!

Mother Mary said...

Do you have any speculatory explanations on vestigial structures,like the limbs of the amphiumas?

Kelly said...

We don't have a complete fossil record, and none of us has been around long enough to know. That said, if amphiumas had ancestors that possessed larger, more functional limbs, but these limbs were a disadvantage by causing more resistance going through soft mud and detritus, individuals in the population with legs on the smaller end of the spectrum would've had an advantage in eating more food and producing more offspring, thus passing their "smaller leg" genes on to future generations. Eventually, you could end up with the tiny legs of the amphiuma.