Pond type vs Stream type larvae

[eljorgo]

Currently I am working in a project when I came with this statement that lead me to doubt:

"Pond type larvae can adapt to streams but stream type larvae can never adapt to ponds"

Because I am not an authority in the Caudate world I wanted to test the truth of this statement. I´ve seen Triturus and Lissotriton adapt to streams with my eyes and have seen reports of Mesotriton doing the same. So yeah pond type larvae can adapt to streams. But I never saw a stream-dweller living in a pond... Its unthinkable... I thought in European species like Salamandra salamandra... Impossible. I thought in American Gyrinophilus, Pseudotriton, Desmognathus, Eurycea seems impossible as well but then I remembered Salamandridae in America... Tarichas... And now I am totally confused about their larvae. I´ve raised some sucessfully last year in muddy ponds but in the web they are referred like Stream type....At least their adults...Live and breed in streams so I really don't know if Taricha and possibly other genus I am forgetting right now are or not a transgression to this Pond-Stream type "rule".

I´ve made a short list some days ago that now its making me confuse...
I guess that all I have written is correct but are really Taricha a stream-dweller larvae with adaptations to pond life? There are other species known of you that practise this "transgression"?

Pond type: Cynops; Triturus; Lissotriton; Mesotriton; Ommatotriton; Tylototriton; Ambystoma (some species); Taricha; Notophthalmus; Hynobius (some species); Pleurodeles;

Both: (Pond type with adaptation to streams): Triturus; Lissotriton; Mesotriton; Ommatotriton..........more?

Stream type: Paramesotriton; Laotriton; Pachytriton; Pseudotriton; Desmognathus; Neurergus; Euproctus; Calotriton; Ambystoma (some species); Hynobius (some species); Dicamptodon; Salamandra;

Hope someone can take me out from this blindness.
Thanks in advance,
Jorge

 

[Azhael]

I personally don´t see why you would consider S.salamandra as an stream species. They just use whatever mass of water they can find, from areas of low current to tiny pools of water with no movement at all. They do in fact prefer the small, shallow, still pools where they reach higher concentrations (not surprisingly since there´s no fish).

I´m curious about what is considered "adapting" here...and where have you seen Triturus or Lissotriton adapting to an stream environment. Lissotriton can certainly use low current areas, but Triturus has a strong preference for still water.

Additionally, what do you consider a stream? If you are talking about having a current, there are many habitats that do but can´t be considered streams.

 

[slowfoot]

I think the issue here is that 'stream type' larvae tend to be adapted to high oxygen environments - i.e., have gills that are less efficient at absorbing oxygen out of the water and are less likely to be ripped off by strong currents. So they might have difficulty obtaining enough oxygen in still waters. While 'pond type' larvae have gills that will function in low oxygen environments. That's the most obvious issue I can think of.

 

[eljorgo]

@ Slowfoot: You´re right. What you´ve written is very obvious. The problem comes in the situation I mentioned. When some species can habit both the environments. The rest is easy I know. But we´re only focused in these environmental hybridizations.
@ Azhael: I am the one that can´t see how you consider them as a not stream-dweller species. I´ve seen them in the wild and I´ve read lots and seen documentaries and i dont know more what to say... They are only stream inhabitants...that's all.
To me a stream were Salamandra habit haves:
-Dark floor
-Slow to medium current (factor to rich Oxygen concentrations)
-Really shallow (factor to rich Oxygen concentrations)
-Ice cold water (factor to rich Oxygen concentrations)
-The water is almost potable (No colour, no smell, none or very very few detritus in suspension and that begins in a spring somewhere in a mountain)
When I said adapting I meant adapting. Simple as prosper in other environments that are not so used for that same specie.

I´ve seen both T. marmoratus and L. Boscai in north portugal bettwen 250 and 400m in small to medium streams. In fact you are right in the point that I saw triturus in the more lentic stream while boscai was in a more "faster" lets say.

I would love you to tell me witch other habitats have current and are not streams excluding lowland rivers and those sort or truly lentic green waters.

Hope that helped,
Jorge

 

[Azhael]

I would love you to tell me witch other habitats have current and are not streams excluding lowland rivers and those sort or truly lentic green waters.

How about the king of caudate habitats, the trough. It´s got a current, it´s definitely not a stream, and they are of particular atraction for many caudates.
There´s a big difference between inhabiting a stream and being a stream adapted species. I´ll explain myself...
Inside a stream there are different microhabitats. S.salamandra, as well as L.boscai or L.helveticus, frequently inhabits streams in some areas of their distribution (although the main populations of Lissotriton are found in pools). They, however, always inhabit the very same microhabitats, which are the low current pools that are left on the sides of the main current in most small streams. The larvae do not dwell in the main current and are unable to move from one pool to another except by being swept by.They in fact actively avoid the areas with stronger current. So basically, they are only inhabiting a portion of the stream. A portion which is basically a pool. The only differences between one of these pools and a regular pool (such as would be inhabited by P.waltl) are size, the pressence of a minor current and oxygen levels. The oxygen levels would be the main factor, despite the fact that caudate larvae can adapt the length and volume of their external gills in order to keep up with the oxygen levels that surround them.

That´s why your assumption that pond-type larvae can "adapt" to streams is quite true. The reason, however, is that they are inhabiting microhabitats that are in essence pools, which are what the main populations use. That´s also why for example in the ocassions when they inhabit rivers they are only present in the sand banks and other protected, low-current microhabitats.

S.salamandra larvae like well oxygenated water but certainly dislike strong currents. That´s why i would never consider it a stream species, because they only use the slow-current pools. When compared to stream-specialists that dwell in the current and are able to move up and down the stream, they are using completely different habitats.

 

[Nathan]

"Pond type larvae can adapt to streams but stream type larvae can never adapt to ponds"

Nonsense.

Several Eurycea species occasionally or habitually breed in slack water lakes, ponds, and swamps. Some, such as E. cirrigera, and E. guttolineata, have stream-type larvae, while others, such as E. quadridigitata and E. chamberlaini, have intermediate larvae.

Some Desmognathus species also occasionally breed in slack water, including D. auriculatus and D. conanti (each of which is probably a species complex). They have stream-type larvae.

Stereochilus marginatus are swamp-breeders. Its larvae have a pond-type morphology at hatching but quickly develop a stream-type morphology.

Even cold-water-specialists, such as Dicamptodon copei, D. tenebrosus, and Necturus maculosus, may breed in chilly lakes or ponds.

 

[eljorgo]

Well I saw two things that spot a lot my interest. You are right in them both. I think this divergence in opinions between we two is what he consider or not a stream. I would said that those places you find L. helveticus are pools. Their are in fact. But i would consider them as a hole, as a stream. Streams are very different i know. Some can be totally hostile for larvae with so strong water flows that wash every thing to the sea. Others like those you mentioned are more lentic and justify the presence of L. helveticus who seems to enjoy the lentic waters at some parcels. how ever Its my duty to tell you I´ve seen L.boscai in a considerable flowing stream just before a water fall, the flush was considerable, water was cold and most surprising there were no pools more protected from the current. What there was were many aquatic plants in both the sides that made a protective shield to the water flow to both adults and larvae of L.boscai. But even that way I saw some larvae with small dimensions standing just before the waterfall with no protection of any-plants. Just grabbed to the sandy floor.
I might add also that I found S.s.gallaica larvae in a stream I don't have any photos but I really wanted you to see so i made these images in a short time you to see what I mean. Like i never took cameras to the field I dont have only one picture of herping
so here it goes in some easy schemes of the streams:

S.s.gallaica

Even they habit pools between successive waterfalls the hole thing is a stream.. I mean the water they breath from was from last waterfall and are going to the next one... I mean it doesn't stop Its a hole together, a stream either having slower or faster flow.
Here in Madeira of-course most streams are more than deadly I don't talk of those high super flush streams:

L.boscai and C. lusitanica:

The P means presence and in last pic you can see that presence was much bigger in the side were the current was smaller because of the curvature (the schemes are real, those were the places I saw them in.)
I am not an artist but I really hate to be explaining someone without that same person cant see what I see so here I give some examples of what i saw.

You also mentioned stream-specialists that dwell in the current and are able to move up and down the stream...I never heard of a larvae be able to do such (only if they get partially out of the water)...Witch ones are you talking about?

Cheers,

 

[eljorgo]

Thanks Nathan! nice! Data that take that statement partially down. Well in european-chinese species I think it would be really accurate but I have totally ZERO experience with American species. Even so I have read about many but lacked the Eurycea that seem to be the most contradictory for that statement. In fact from what I can take from your post its not so contradictory. Based stream type salamanders will only lay and their larvae will prosper if the habitat have stream characteristics . Because if you take the example of a good lake that haves less than 0,50m depth (usually much less); lots of algae; and temps surrounding 22ºC I really don´t believe any of those will live in such waters... While for example Triturus larvae would make a party at.
Conclusion: they will breed in other waters than streams but that have many common factors like temperature. The smaller the temps the more high in oxygen it will be.
True or false? Tell me what you really think because I really want to know it well.
There is a contradiction to the conclusion I just made based on your facts?
Cheers,
Jorge

 

[Nathan]

Your conclusions are correct for Necturus, Dicamptodon, and similar, but not for the plethodontids.

I have collected D. conanti, E. cirrigera, and E. guttolineata in the conditions you describe- warm, shallow, vegetated wetlands. This is also typical habitat for E. quadridigitata, E. chamberlaini, and S. marginatus. These animals inhabit the southeastern US, where there are no natural deep, cold, lakes.

Just to be clear- when I say "stream type" or "pond type" larvae I am referring to morphology. Stream type larvae have the dorsal fin origin at the base of the tail and relatively short gills, while pond type larvae have dorsal fin origin on the trunk and relatively long gills. Are these the same definitions you are using?

 

[eljorgo]

Your conclusions are correct for Necturus, Dicamptodon, and similar, but not for the plethodontids.

Happy to hear it.

I have collected D. conanti, E. cirrigera, and E. guttolineata in the conditions you describe- warm, shallow, vegetated wetlands. This is also typical habitat for E. quadridigitata, E. chamberlaini, and S. marginatus. These animals inhabit the southeastern US, where there are no natural deep, cold, lakes.

When you say warm you talk about witch temperatures? My definition of warm or cold may be a bit different from yours in fact. And was the water translucent or it had matter in suspension?

Just to be clear- when I say "stream type" or "pond type" larvae I am referring to morphology. Stream type larvae have the dorsal fin origin at the base of the tail and relatively short gills, while pond type larvae have dorsal fin origin on the trunk and relatively long gills. Are these the same definitions you are using?

Obviously that yes. I may be distracted some times but not dumb.
Cheers,

 

[Nathan]

I didn't mean to imply you were dumb, just making sure we were on the same page! :happy:

I would estimate maximum water temps in these habitats at 70-80 F (21-27 C). These were clear to moderately turbid waters. I have not found stream-type larvae in exposed, highly turbid ponds (such as livestock ponds) that get very warm (30 C +), only Ambystoma and Notophthalmus larvae.

 

[eljorgo]

Nice. Thanks for all the data. Really appreciated! Have you spotted Taricha larvae in habitat? I suppose that they are pond type? Or not really? In fact many of the adults from its species are stream-dwellers if not all...
Cheers,

 

[Nathan]

I have no personal experience with Taricha. I haven't had a chance to do any herping on that side of the continent yet. Hopefully some of our westerners can chime in.

Petranka (Salamanders of the United States and Canada) says that the larvae of all three Taricha species are pond-type, but that T. rivularis has a reduced dorsal fin compared to the other two. T. rivularis and T. torosa sierrae tend to breed in swift streams, while T. granulosa and T. t. torosa tend to breed in sluggish streams, pools, or ponds.

 

[eljorgo]

Hey Nathan thanks on the info!
Lets hope some westerners join this.
Cheers,