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Conserving Rare Salamanders; Spotted Sal study

SludgeMunkey

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Frank, I am curious of your stance on these findings.

I personally wonder if there are dormant traits in these species left over from the days a few million years back when brackish type and saline waters were more common as amphibian habitats.
 

findi

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Frank, I am curious of your stance on these findings.

I personally wonder if there are dormant traits in these species left over from the days a few million years back when brackish type and saline waters were more common as amphibian habitats.

Hi,

Interesting thought, thanks. We cannot really tell, as far as I know. This seems to be a recent adaptation, but whether or not it is helped along by their evolutionary history is difficult to know. Spotted salamanders, evolved a highly terrestrial lifestyle, taking them away from water early on, but also causing them to breed in tiny fish-free pools that have high concentrations of natural salts and minerals, in addition to pollution. And as water levels drop, these concentrations become higher. So rapid adaptation would be to their advantage (hopefully rapid enough to keep up with what ewe do to them!).

There are a few salt-tolerant amphibians, most notably SE Asia's Crab-eating Frog, an amazing beast. African clawed frogs survive in sometimes brackish pools along the coast of the UK (introduced population), and American and Fowlers Toads have been found breeding in brackish tidal ponds.

Keep the ideas coming...that's how we discover new things, and there are many left!

Best, Frank
 

FrogEyes

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I can't see salt tolerance as a holdover of ancient "amphibians", as modern amphibians are no more related to extinct marine or brackish creatures than we are. The most basal salamanders are largely associated with mountain streams (Cryptobranchidae, most genera of Hynobiidae), as are many of the most basal living frogs (Ascaphidae, Leiopelmatidae, Megophryidae). Salt tolerance is often associated with the most "advanced" species (Salamandra in Portugal, Salamandridae; Ambystoma in Mexico, Ambystomatidae; Bufo in Europe and Anaxyrus in NA, Bufonidae; Fejervarya in Asia, Dicroglossidae; Platymantis in Melanesia/Micronesia, Ceratobatrachidae).

It's notable that in Ambystoma, a single highly complex clade adapted to arid environments has developed mountain stream, saline lake, and highly adaptable species. Likely the aquatic life phase creates aquatic opportunities like streams, while terrestrial adaptation to aridity creates pre-adaptation for saline tolerance. The related Dicamptodon is also stream-adated, at least in extant species. Extinct species of dicamptodontid were likely more variable in habitat.
 

findi

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I can't see salt tolerance as a holdover of ancient "amphibians", as modern amphibians are no more related to extinct marine or brackish creatures than we are. The most basal salamanders are largely associated with mountain streams (Cryptobranchidae, most genera of Hynobiidae), as are many of the most basal living frogs (Ascaphidae, Leiopelmatidae, Megophryidae). Salt tolerance is often associated with the most "advanced" species (Salamandra in Portugal, Salamandridae; Ambystoma in Mexico, Ambystomatidae; Bufo in Europe and Anaxyrus in NA, Bufonidae; Fejervarya in Asia, Dicroglossidae; Platymantis in Melanesia/Micronesia, Ceratobatrachidae).

It's notable that in Ambystoma, a single highly complex clade adapted to arid environments has developed mountain stream, saline lake, and highly adaptable species. Likely the aquatic life phase creates aquatic opportunities like streams, while terrestrial adaptation to aridity creates pre-adaptation for saline tolerance. The related Dicamptodon is also stream-adated, at least in extant species. Extinct species of dicamptodontid were likely more variable in habitat.


Hi,

Thanks for your feedback; interesting ideas - I'm in touch with someone working on a related subject at the AMNH here in NYC but am not familiar enough with her research to comment in detail. From past conversations, I gather that generalizations are very difficult to make. Adaptation forced by environment comes into play across a variety of families- some high-altitude Telmatobius spp., i.e. the Lake Titicaca Frog, are well adapted to waters high in dissolved salts and other minerals, despite being considered relatively "primitive" .

The tiger salamander relatives you mention are quite amazing - some of the habitats they've adapted to, especially in Mexico, seem to push the bounds of what is possible for an amphibian.

Best, Frank
 
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