SoCal desperation herping 1
Moderator: Scott Waters
SoCal desperation herping 1
The late August-early September interval, before hatchling snakes emerge, equals only November in its ability to completely suck. Sometimes a fella has to engage in what I refer to as "desperation herping", whereby some site that you really couldn't have been bothered with at a better time of year might start to seem a little less barren and boring. Especially if it might have some water, since even large streams around here are bone-dry by now. Any kind of water is better than none.
Already low on the list of places worth looking at, cattle ponds are really special now -- you can almost but not quite stand on the fluid (which consists of approximately equal volumes of cow urine and liquified poo), the mud is real goopy and knee deep plus, and the downwind side has both the smell and the flies. All these qualities might be why I ended up going to this place alone yesterday.
You really don't want to step in it, and it might take half an hour to wade across, which is why a net and lots of rope is a good idea. The "water-like fluid" part is not real deep. We use skis on the bottom of the net frame to keep it from digging into the bottom, and this works really well in even the slimiest of ponds.
And this time there's something in the net other than biting water beetles and backswimmers:
Matter of fact there were a heap of them:
Let's wash them off a bit and see what we've got here:
OK, tiger salamanders, and we're less than a mile from the edge of the known range of Ambystoma californiense, but these guys are 6-8" long, too large for metamorphosing A. californiense, and their coloration, pattern and head shape are all wrong. They are introduced barred tiger salamanders, Ambystoma mavortium, making another in a series of infested ponds within a couple of miles of the range of the native species (see an earlier post for a report on another site, viewtopic.php?f=2&t=1145).
There were still a few larvae left in the pond (12 of 74, to be exact), and they don't look anything like larval Ambystoma californiense. One day I need to make a "how to tell apart" post for tiger salamander larvae, but I'm still missing a couple of critical photos. Basically the nonnative larvae have narrower snouts but broader gill bases, stouter limbs and feet, and more pointed tail tips than the natives, plus some differences in coloration particularly as they approach metamorphosis.
Most of the animals in this sample are metamorphs, but they have remained in the pond for at least two months since losing their gills. This is not something that the natives seem to be able or willing to do, even when ponds retain water well into the fall. Compared to the native species, metamorphosed A. mavortium have more pale markings that tend to be yellow (vs. cream or white), with irregular outlines (vs. being neat ovals). There are usually large pale areas on the head, the snout is domed (vs. flat in A. californiense), and the limbs and feet are more robust.
Exotics pose serious problems for native herps in many places. Barred tiger salamanders are right up there with bullfrogs and red-eared sliders in invasive potential. When you have the opportunity, do a little desperation herping in the slow times of year -- target exotics and try to clean some of these things out.
Already low on the list of places worth looking at, cattle ponds are really special now -- you can almost but not quite stand on the fluid (which consists of approximately equal volumes of cow urine and liquified poo), the mud is real goopy and knee deep plus, and the downwind side has both the smell and the flies. All these qualities might be why I ended up going to this place alone yesterday.
You really don't want to step in it, and it might take half an hour to wade across, which is why a net and lots of rope is a good idea. The "water-like fluid" part is not real deep. We use skis on the bottom of the net frame to keep it from digging into the bottom, and this works really well in even the slimiest of ponds.
And this time there's something in the net other than biting water beetles and backswimmers:
Matter of fact there were a heap of them:
Let's wash them off a bit and see what we've got here:
OK, tiger salamanders, and we're less than a mile from the edge of the known range of Ambystoma californiense, but these guys are 6-8" long, too large for metamorphosing A. californiense, and their coloration, pattern and head shape are all wrong. They are introduced barred tiger salamanders, Ambystoma mavortium, making another in a series of infested ponds within a couple of miles of the range of the native species (see an earlier post for a report on another site, viewtopic.php?f=2&t=1145).
There were still a few larvae left in the pond (12 of 74, to be exact), and they don't look anything like larval Ambystoma californiense. One day I need to make a "how to tell apart" post for tiger salamander larvae, but I'm still missing a couple of critical photos. Basically the nonnative larvae have narrower snouts but broader gill bases, stouter limbs and feet, and more pointed tail tips than the natives, plus some differences in coloration particularly as they approach metamorphosis.
Most of the animals in this sample are metamorphs, but they have remained in the pond for at least two months since losing their gills. This is not something that the natives seem to be able or willing to do, even when ponds retain water well into the fall. Compared to the native species, metamorphosed A. mavortium have more pale markings that tend to be yellow (vs. cream or white), with irregular outlines (vs. being neat ovals). There are usually large pale areas on the head, the snout is domed (vs. flat in A. californiense), and the limbs and feet are more robust.
Exotics pose serious problems for native herps in many places. Barred tiger salamanders are right up there with bullfrogs and red-eared sliders in invasive potential. When you have the opportunity, do a little desperation herping in the slow times of year -- target exotics and try to clean some of these things out.
-
- Posts: 8025
- Joined: June 8th, 2010, 8:12 am
- Location: Hesperia, California.
- Contact:
Re: SoCal desperation herping 1
Wow... that's just....Wow. Happy to say that I've only seen several bullfrogs this year, in Arroyo habitat... and plenty of Arroyos...
jim
jim
Re: SoCal desperation herping 1
That is unfortunate, but an awesome method and anywhere in their native range would be great fun to see. Thanks for the post.
Re: SoCal desperation herping 1
That is just amazing Sam. Great photo doc! A couple of those would almost make an artsy poster!
Re: SoCal desperation herping 1
Great post, Sam. Sad to have such a thriving population so close to the natives. Up here, most of the larvae transformed as the vernal ponds were drying up in late May to June, but I did find a water bug eating a transformed 4" one on Friday, so I it seems californiense may actually hang out in the pond after transformation (see my Friday post this forum).
Re: SoCal desperation herping 1
I did see that post, Owen, but I couldn't tell from the photos how recently the animal had metamorphosed (it appeared to be pale olive dorsally?).
We have A. californiense larvae still in ponds here, but they're not yet close to metamorphosis. Mostly I think this is a matter of water quality first, food resources second -- if both persist, the larvae are in no rush to metamorphose. What *is* different, in my experience, is as I commented in the post: I have never found californiense that were more than a week or so past metamorphosis remaining in a pond, whereas mavortium metamorphs may remain aquatic for several months (even when pond quality stinks). Down here leaving a pond is risky business because the landscape is extremely dry. A juvenile salamander doesn't have very long to find a safe burrow before it becomes a pretzel.
We have A. californiense larvae still in ponds here, but they're not yet close to metamorphosis. Mostly I think this is a matter of water quality first, food resources second -- if both persist, the larvae are in no rush to metamorphose. What *is* different, in my experience, is as I commented in the post: I have never found californiense that were more than a week or so past metamorphosis remaining in a pond, whereas mavortium metamorphs may remain aquatic for several months (even when pond quality stinks). Down here leaving a pond is risky business because the landscape is extremely dry. A juvenile salamander doesn't have very long to find a safe burrow before it becomes a pretzel.
Re: SoCal desperation herping 1
Great post Sam.
- Gluesenkamp
- Posts: 290
- Joined: June 8th, 2010, 7:57 am
- Location: Texas
Re: SoCal desperation herping 1
Disturbing find, Sam. I have seen the same thing around Prunedale. Cattle tanks were full of honker larvae, probably mavortium and some possible mav-cal hybrids. Several weeks later, the same ponds yielded californiese larvae and those big aquatic mavs. There were at least two seperate emergences and lots of hybrids in the mix. Bad ju-ju.
-
- Posts: 81
- Joined: June 9th, 2010, 10:32 am
Re: SoCal desperation herping 1
Sam -- What do you do with them considering they are not native and so close to our native tiger?
Great stuff.
Great stuff.
Re: SoCal desperation herping 1
Rick,
They have accepted my invitation to join the world-famous UCSB herpetological collection, where they have many friends.
They have accepted my invitation to join the world-famous UCSB herpetological collection, where they have many friends.
- Gluesenkamp
- Posts: 290
- Joined: June 8th, 2010, 7:57 am
- Location: Texas
Re: SoCal desperation herping 1
Amen to that.
-
- Posts: 81
- Joined: June 9th, 2010, 10:32 am
Re: SoCal desperation herping 1
Awesome. I believe it is now illegal in California to possess non-native Ambystoma species so without permit they are still hands off.
- Berkeley Boone
- Posts: 878
- Joined: June 8th, 2010, 4:02 am
Re: SoCal desperation herping 1
Sam-
I sent you a PM.
--Berkeley
I sent you a PM.
--Berkeley
Re: SoCal desperation herping 1
Sam,
Awesome post as usual. Just t comment on your A. californiense observation. I have a study system that I have visited monthly for the last two years. Last October we drained the pond to remove Largemouth Bass, Bullfrogs and Mosquitofish - the mosquitofish populations were severely depressed, but with late summer water temps, breeding has exploded in the last month or so.
Anyway, in 7 years of monitoring, we never saw CTS of any lifestage in the pond. Post-draining, we saw a huge breeding bloom of CTS this year and they have been hanging out in the pond since June as metamorphs. But similar to your site, the surrounding area is pretty arid - not as arid as So Cal though. Admittedly, I haven't seen this before either, but neither do I typically monitor CTS ponds into August.
Cheers,
Rob
Awesome post as usual. Just t comment on your A. californiense observation. I have a study system that I have visited monthly for the last two years. Last October we drained the pond to remove Largemouth Bass, Bullfrogs and Mosquitofish - the mosquitofish populations were severely depressed, but with late summer water temps, breeding has exploded in the last month or so.
Anyway, in 7 years of monitoring, we never saw CTS of any lifestage in the pond. Post-draining, we saw a huge breeding bloom of CTS this year and they have been hanging out in the pond since June as metamorphs. But similar to your site, the surrounding area is pretty arid - not as arid as So Cal though. Admittedly, I haven't seen this before either, but neither do I typically monitor CTS ponds into August.
Cheers,
Rob
-
- Posts: 523
- Joined: June 11th, 2010, 9:09 pm
- Location: Edmonton, Alberta
Re: SoCal desperation herping 1
The mavortium that I find are way on the northern edge of the range and look quite different than those. Not surprising, if you had said those were a bucket full of california t.sal's I would've been tricked. That is a really cool way to catch them though; I use minnow traps. However your pond has next to no vegetation in it. Anyhow, rambling aside, I find adult A.mavortium in Alberta and Saskatchewan into August. I think a lot of them hang around all summer after breeding for the easy food. Into September everything has left the ponds and I don't find them again until late May or June- well, April some years; this year was a late spring.
Ian
Ian
Re: SoCal desperation herping 1
onya Sam, cool post
Re: SoCal desperation herping 1
There are a couple of interesting points coming out here -- Rob, you say there are metamorphosed A. californiense that have been resident in the pond for at least two months post-metamorphosis. I am assuming these are known to be pure californiense rather than introgressed with mavortium genes. Do you know if these guys have developed adult coloration? Pity you can't pull some out and hold them overnight to see if they defecate. As far as I am aware, metamorphosed A. californiense are physically unable to feed under water, and won't even try. At least some of the eastern tiger salamanders, mavortium included, can and will feed underwater as fully metamorphosed adults. They are not very good at it, but they won't starve.
I have twice seen A. californiense larvae remain in ponds through the summer and fall; sampling in early December (before any appreciable rain) we got hundreds of 3" larvae at one site, and at another a half-dozen 5-6" animals that had gill stubs and normal metamorph color, but were just twice as large and 5 months late. Otherwise, in my experience down here you do not see fully metamorphosed juvenile A. californiense remaining in ponds.
The other issue concerns how the nonnative A. mavortium have adapted to California conditions. They are native to areas where midwinter activity is highly constrained, and they breed during a summer rainy season. In California there is normally no rain in summer, and the evidence at hand is that mavortium have switched to winter breeding, just like A. californiense. That's not as simple a shift as it sounds, because it involves resetting the endocrinological cues that cause maturation of sperm and ova -- say, for example from being triggered by increasing daylength to decreasing daylength. We have some evidence that nonnatives will try to breed in summer as well, although it is usually not possible to have two cohorts of larvae of greatly different sizes in the one pond.
I had initially assumed that all of the animals mentioned in this post were of the same age -- juveniles ca. 7-8 months old, about 3 months past metamorphosis. However, in the course of swabbing animals for chytrid analyses today we noted one male that is fully sexually mature, and thus probably at least 2-3 years old, and a female that looks to be gravid, mixed in with the rest. I suspect that these are "leakers" that came to the pond sometime during the summer, rather than adults that remained there from the winter.
This evident plasticity in breeding responses is obviously a good attribute for an invasive species.
I have twice seen A. californiense larvae remain in ponds through the summer and fall; sampling in early December (before any appreciable rain) we got hundreds of 3" larvae at one site, and at another a half-dozen 5-6" animals that had gill stubs and normal metamorph color, but were just twice as large and 5 months late. Otherwise, in my experience down here you do not see fully metamorphosed juvenile A. californiense remaining in ponds.
The other issue concerns how the nonnative A. mavortium have adapted to California conditions. They are native to areas where midwinter activity is highly constrained, and they breed during a summer rainy season. In California there is normally no rain in summer, and the evidence at hand is that mavortium have switched to winter breeding, just like A. californiense. That's not as simple a shift as it sounds, because it involves resetting the endocrinological cues that cause maturation of sperm and ova -- say, for example from being triggered by increasing daylength to decreasing daylength. We have some evidence that nonnatives will try to breed in summer as well, although it is usually not possible to have two cohorts of larvae of greatly different sizes in the one pond.
I had initially assumed that all of the animals mentioned in this post were of the same age -- juveniles ca. 7-8 months old, about 3 months past metamorphosis. However, in the course of swabbing animals for chytrid analyses today we noted one male that is fully sexually mature, and thus probably at least 2-3 years old, and a female that looks to be gravid, mixed in with the rest. I suspect that these are "leakers" that came to the pond sometime during the summer, rather than adults that remained there from the winter.
This evident plasticity in breeding responses is obviously a good attribute for an invasive species.
Re: SoCal desperation herping 1
Sam,
Yes, they are fully metamorphosed, displaying full adult coloration. And you are correct - the population I'm referencing is well inside even the front for the most aggressive model of hybrid introgression.
In mid-June, they were just finishing resorbing the last of their gill rakers. I observed several, of these fully metamorphosed animals in late Aug, and I'm intending to head back out tomorrow evening. Interesting about the feeding limitation. I've never heard of that. I did find one metamorph on the crawl in July near the pond, and showed no signs of dispersing - perhaps out foraging? There were certainly far fewer metamorphs in Aug than larvae in June.
I will report back on if we find any tomorrow night. And unfortunately, my permit doesn't allow for holding animals over.
Cheers,
Rob
Yes, they are fully metamorphosed, displaying full adult coloration. And you are correct - the population I'm referencing is well inside even the front for the most aggressive model of hybrid introgression.
In mid-June, they were just finishing resorbing the last of their gill rakers. I observed several, of these fully metamorphosed animals in late Aug, and I'm intending to head back out tomorrow evening. Interesting about the feeding limitation. I've never heard of that. I did find one metamorph on the crawl in July near the pond, and showed no signs of dispersing - perhaps out foraging? There were certainly far fewer metamorphs in Aug than larvae in June.
I will report back on if we find any tomorrow night. And unfortunately, my permit doesn't allow for holding animals over.
Cheers,
Rob
Re: SoCal desperation herping 1
I've now got a question about how you identify hybrids without testing. Of the 5 adults that I've seen this year (4 flipped), 3 of them were olive colored and different looking from what I had been used to. All were frrom the same pond (Bullfrogs and Red-legged Frogs present here as well):
While the size (7" to 8"), patern of spots definitely puts them typical for A. californiense, the olive color seemed a bit different. This one was found on a day where it rained a couple hours prior and was in water in a different pond over 2 miles away. Color is more what I would call typical:
Anyway, any thoughts on the color difference would be appreciated.
While the size (7" to 8"), patern of spots definitely puts them typical for A. californiense, the olive color seemed a bit different. This one was found on a day where it rained a couple hours prior and was in water in a different pond over 2 miles away. Color is more what I would call typical:
Anyway, any thoughts on the color difference would be appreciated.
Re: SoCal desperation herping 1
And I have been submitting myself to sleeping outside after a cattle pond salamander hunt all this time (wife won't let me in the house). Great post!
Re: SoCal desperation herping 1
I don't think that hybrids can be reliably identified without genetic testing. While there are consistent morphological differences between A. californiense and A. mavortium (and other members of the A. tigrinum complex), they seem to be polygenic characters that fall apart quickly in hybrids. Pure or nearly pure animals are fairly distinctive, however.
As adults, A. californiense have relatively flat snouts, their eyes are large and directed laterally at about 30 degrees above horizontal, and the jaw adductor muscles are relatively small, which has two consequences. Most conspicuously, their heads are widest at the angle of the jaws and are parallel-sided or narrowing behind that. There is also an impressed groove extending downwards and backwards behind the eye (marking the edges of muscle bundles beneath) that is much more prominent in A. mavortium. Adult A. mavortium have strongly domed snouts, eyes are smaller and nearer to a 45 degree angle, and the jaw muscles are heavier -- together with a somewhat narrower, more pointed snout this makes the head outline wider behind the angle of the jaws. Native A. californiense tend to be mostly black dorsally, with small oval pale spots on the trunk, whereas many populations of exotics are definitely not mostly dark dorsally, and have larger, much more irregular pale markings. Also most A. californiense are pale ventrally, whereas many mavortium are partly or mostly dark beneath. These are generalities that should not be taken as absolute statements since there is a fair bit of variation across populations of native tiger salamanders, and massive variation in the exotics, which came from many different sources and sometimes have quite distinct types mixed in a single pond. All bets are off with hybrids (which of course can range from > 99% to less than 1% native genes).
The terrestrial animals in your photos are consistent with what we see here, in that the dark dorsal color tends to go toward olive (or at least get paler) when the animals have been in upland sites for a while. These guys can change their ground color in a short time -- coal black animals entering a muddy pond can be pale gray by morning. Almost all the animals I see out traveling are quite dark, but those found under cover or in ponds can be fairly pale.
As adults, A. californiense have relatively flat snouts, their eyes are large and directed laterally at about 30 degrees above horizontal, and the jaw adductor muscles are relatively small, which has two consequences. Most conspicuously, their heads are widest at the angle of the jaws and are parallel-sided or narrowing behind that. There is also an impressed groove extending downwards and backwards behind the eye (marking the edges of muscle bundles beneath) that is much more prominent in A. mavortium. Adult A. mavortium have strongly domed snouts, eyes are smaller and nearer to a 45 degree angle, and the jaw muscles are heavier -- together with a somewhat narrower, more pointed snout this makes the head outline wider behind the angle of the jaws. Native A. californiense tend to be mostly black dorsally, with small oval pale spots on the trunk, whereas many populations of exotics are definitely not mostly dark dorsally, and have larger, much more irregular pale markings. Also most A. californiense are pale ventrally, whereas many mavortium are partly or mostly dark beneath. These are generalities that should not be taken as absolute statements since there is a fair bit of variation across populations of native tiger salamanders, and massive variation in the exotics, which came from many different sources and sometimes have quite distinct types mixed in a single pond. All bets are off with hybrids (which of course can range from > 99% to less than 1% native genes).
The terrestrial animals in your photos are consistent with what we see here, in that the dark dorsal color tends to go toward olive (or at least get paler) when the animals have been in upland sites for a while. These guys can change their ground color in a short time -- coal black animals entering a muddy pond can be pale gray by morning. Almost all the animals I see out traveling are quite dark, but those found under cover or in ponds can be fairly pale.
Re: SoCal desperation herping 1
Thanks Sam. Unfortunately, I can't check the ventral coloring (hands off stuff, you know). I do know that our local Coyote Bait and Tackle used to sell "water dawgs" as bait, so you can never be to sure up here in Santa Clara County. So far, californiense in 5 ponds (3 are now dry) and R. draytonii in 3 ponds, 3 creeks, so it seems my protected stuff is doing OK for the time being.
-
- Posts: 2288
- Joined: June 7th, 2010, 9:52 pm
- Location: Amarillo, Texas
Re: SoCal desperation herping 1
sad part is I'd *love* to get my hands on some of those neotenic tigers for pets Sucks seeing an animal you have to bust your butt to find locally overrunning an area it's not native to
Re: SoCal desperation herping 1
Paul,
It oughn't be too hard to find a source of neotenic Ambystoma up your way. Years ago there was a famous site at Reese AFB just W of Lubbock (http://www.jstor.org/stable/3891064?seq=2), and in general secondary sewage treatment ponds are heaven for these things, so follow your nose. Barring that, check with some local bait dealers.
It oughn't be too hard to find a source of neotenic Ambystoma up your way. Years ago there was a famous site at Reese AFB just W of Lubbock (http://www.jstor.org/stable/3891064?seq=2), and in general secondary sewage treatment ponds are heaven for these things, so follow your nose. Barring that, check with some local bait dealers.
Re: SoCal desperation herping 1
Great post. As a reptile guy with almost no experience with salamanders (they're absent from Australia), I have an ignorant question: When referring to metamorphosed salamanders remaining in ponds, I presume they lead a life similar to adult, fully aquatic newts? i.e. they must surface to breathe, given that they've lost their external gills. Under normal conditions, what is the trigger for them to become terrestrial?
Re: SoCal desperation herping 1
Larval Ambystoma can respire via gills, skin or lungs. Their metabolic rates are pretty low, so as long as water remains cool and well-mixed (vs. stratified) they can get all the oxygen they need without using their lungs. Water can hold less oxygen at higher temperatures, and decomposition of organic material can deplete oxygen to almost nothing -- that's when you get animals coming to ther surface to gulp air. In some circumstances they will also develop very elaborate gills in response to low dissolved oxygen:
As larvae metamorphose the external gills and their circulatory loops and supportive cartilages all regress. Smaller species and animals in cool environments can often get by on cutaneous respiration alone. As size increases or it becomes increasingly difficult to maintain a moist skin you see a shift to breathing via the mouth lining and lungs.
Metamorphosis is triggered by any of several environmental stressors acting alone or together. Reduced water volume or quality, low oxygen saturation, increased hardness, salinity or crowding, lack of food or enhanced hassling by predators can each result in larvae starting to metamorphose, providing that they have reached a size where they are capable to doing so. The specific cause is a spike in production of the hormone thyroxine by the animals' thyroid glands. Metamorphosis is irreversible -- adults returning to water to breed in subsequent years will not redevelop gills, larval skeletal features, lateral line organs or any of the other unique features of larvae. About all that may happen is enlargement of tail fins and some thickening of the skin.
In many cases amphibian larvae can grow much more quickly in water than as metamorphosed juveniles on land, and this can be significant. For example, spadefoot toad tadpoles that spend an extra 2 months in a pond can reach sexual maturity 2-3 years earlier than tadpoles that left the pond at small size. Also, larger toadlets have fewer predators, so the number that survive to breeding age can be doubly enhanced. Still, this is a risky strategy, and most of the amphibians that have flexible larval periods also have the ability to gear up and metamorphose quickly if conditions begin to go south in a hurry. It's too late already, below:
As larvae metamorphose the external gills and their circulatory loops and supportive cartilages all regress. Smaller species and animals in cool environments can often get by on cutaneous respiration alone. As size increases or it becomes increasingly difficult to maintain a moist skin you see a shift to breathing via the mouth lining and lungs.
Metamorphosis is triggered by any of several environmental stressors acting alone or together. Reduced water volume or quality, low oxygen saturation, increased hardness, salinity or crowding, lack of food or enhanced hassling by predators can each result in larvae starting to metamorphose, providing that they have reached a size where they are capable to doing so. The specific cause is a spike in production of the hormone thyroxine by the animals' thyroid glands. Metamorphosis is irreversible -- adults returning to water to breed in subsequent years will not redevelop gills, larval skeletal features, lateral line organs or any of the other unique features of larvae. About all that may happen is enlargement of tail fins and some thickening of the skin.
In many cases amphibian larvae can grow much more quickly in water than as metamorphosed juveniles on land, and this can be significant. For example, spadefoot toad tadpoles that spend an extra 2 months in a pond can reach sexual maturity 2-3 years earlier than tadpoles that left the pond at small size. Also, larger toadlets have fewer predators, so the number that survive to breeding age can be doubly enhanced. Still, this is a risky strategy, and most of the amphibians that have flexible larval periods also have the ability to gear up and metamorphose quickly if conditions begin to go south in a hurry. It's too late already, below:
-
- Posts: 8025
- Joined: June 8th, 2010, 8:12 am
- Location: Hesperia, California.
- Contact:
Re: SoCal desperation herping 1
Back in the mid 70's, I kept some 'water dogs' that I had bought as bait, as pets...they lived in a 30 gall washtub for what seemed like the better part of a year...and got HUGE. When they finally turned into salamanders they were like a foot long...(10 in at least... ) one yell/blk, one orange/blk. At that time... I though it was pretty cool... jim
Re: SoCal desperation herping 1
Thanks for that excellent answer, Sam. Although I was aware that metamorphosis was irreversible, I wasn't aware that the larval period was quite so plastic or that the size at metamorphosis was variable.
-
- Posts: 523
- Joined: June 11th, 2010, 9:09 pm
- Location: Edmonton, Alberta
Re: SoCal desperation herping 1
Because it hasn't been done, I thought I should point out that neotenic only refers to those larvae that do not undergo metamorphosis and sexually mature in the larval state. If I"m not mistaken, paedomorphism is the retention of larval or juvenile characteristics as an adult.
And because post's are cooler with pictures, and I have some that are somewhat appropriate,
This is one of the largest Ambystoma mavortium I have encountered. (~22cm) It's a new metamorph with gill stubbs just barely apparent, and it's juvenile black colouration. As it gets older it's olive markings will come in.
This is a little larger than average size animal that I find in the minnow traps I use for surveys. (~17cm long) They were found in the same pond, on the same day.
Same species, different province, later in the year. Still very much in the larval form. There were tonnes of adults in the area as well and they could be found on the roads after a rain, or spotlit at night along the shoreline.
Sam, I"m really digging your posts on differentiating the species. It helps me look at my local guys differently, and one day when I come across another species, like in California perhaps, I'll know better what to look for.
Ian
And because post's are cooler with pictures, and I have some that are somewhat appropriate,
This is one of the largest Ambystoma mavortium I have encountered. (~22cm) It's a new metamorph with gill stubbs just barely apparent, and it's juvenile black colouration. As it gets older it's olive markings will come in.
This is a little larger than average size animal that I find in the minnow traps I use for surveys. (~17cm long) They were found in the same pond, on the same day.
Same species, different province, later in the year. Still very much in the larval form. There were tonnes of adults in the area as well and they could be found on the roads after a rain, or spotlit at night along the shoreline.
Sam, I"m really digging your posts on differentiating the species. It helps me look at my local guys differently, and one day when I come across another species, like in California perhaps, I'll know better what to look for.
Ian
- vincemartino
- Posts: 422
- Joined: July 20th, 2010, 5:49 pm
- Location: Central MD/Big Sur, CA
Re: SoCal desperation herping 1
I thank you guys for the education.
-
- Posts: 2288
- Joined: June 7th, 2010, 9:52 pm
- Location: Amarillo, Texas
Re: SoCal desperation herping 1
Correct. I know *of* a great population too, of very large neotenics; my herpetology prof told me about it in college. I just think they look amazingly awesome and would be cool aquarium pets (and I've got an 80 gallon tank so...)neotenic only refers to those larvae that do not undergo metamorphosis and sexually mature in the larval state. If I"m not mistaken, paedomorphism is the retention of larval or juvenile characteristics as an adult.
It's on Pantex land Going herping there is a *great* way to have the feds wreck your day (Pantex being a nuclear weapons disassembly plant--they take security seriously for some reason).
-
- Posts: 523
- Joined: June 11th, 2010, 9:09 pm
- Location: Edmonton, Alberta
Re: SoCal desperation herping 1
My "pappa" in-law works at Pantex; for about a million years. lol, they once gave him a little do-dad with a red light on it. He say's if the light goes on you have 10 seconds to bend over and kiss your ass.
I wonder if I have an "in" on herping their land without getting harrassed. ah, he'll probably be retired before I can make it down there again.
Ian
I wonder if I have an "in" on herping their land without getting harrassed. ah, he'll probably be retired before I can make it down there again.
Ian
Re: SoCal desperation herping 1
Paul, not interested in getting axolotls?Paul White wrote:Correct. I know *of* a great population too, of very large neotenics; my herpetology prof told me about it in college. I just think they look amazingly awesome and would be cool aquarium pets (and I've got an 80 gallon tank so...)
-
- Posts: 2288
- Joined: June 7th, 2010, 9:52 pm
- Location: Amarillo, Texas
Re: SoCal desperation herping 1
Not as much. Neotenic tigers get gigantic and that's frankly part of the appeal; WT had a 12"+ specimen in pickle jar collection (that he used to confuse the hell out of all of us on an ID test). And they look different; thicker in build, more massive, at least if the preserved specimens I've seen were an indicator.
Plus, they're an oddity--a reproducing larva stage for a species that usually metamorphosis. That in and of itself is so flipping weird and piques my interest.
Plus, they're an oddity--a reproducing larva stage for a species that usually metamorphosis. That in and of itself is so flipping weird and piques my interest.
-
- Posts: 523
- Joined: June 11th, 2010, 9:09 pm
- Location: Edmonton, Alberta
Re: SoCal desperation herping 1
I wonder if you could keep the neotenic from metamorphosing once in captivity.
Re: SoCal desperation herping 1
Neotenic A. mavortium can be massive (14") -- going after them with a fly rod has crossed my mind. I have kept quite a few (from unknown original locations, and probably mixed) over the years, in most cases because I wanted to see the range of patterns and colors present in the metamorphosed animals. Some individuals metamorphose quickly in response to less-than-ideal captive conditions (mostly crowding in my case), others more slowly, and some never succeeded, but instead died partway through. There wasn't any strong association between size and ability to transform, except that animals which appeared to have bred at least once as larvae were generally less likely to metamorphose successfully.
In an oversimplified explanation, what's going on with neotenes is a decoupling of the normal association between sexual maturation and metamorphosis. Both are mediated in part by thyroxine, with the endocrinological changes initiated at metamorphosis paving the way for gonadal maturation. In neotenes the ability of tissues other than the gonads to respond to thyroxine is lost (usually by deactivation of one or more genes by any of a zillion possible mutations), and sexual maturation occurs at about the same age, only without metamorphosing. Some Ambystoma species (and populations of others) are obligatorily neotenic and will not metamorphose no matter what treatments you apply, whereas many populations of a number of species are facultatively neotenic -- they will remain as larvae as long as aquatic conditions are good, and may breed as larvae (even with a metamorphosed animal as the other partner), yet will transform if conditions deteriorate. There are also a number of vernal pond-breeding species (including A. californiense) where neoteny has never been documented.
If you want to keep a big larva neotenic, my suggestion would be to hassle it as little as possible during collection and transport, and try to get it feeding immediately as a captive. "Stress" is a trigger, and the less of that, the better is the chance of maintaining a lunker. I reckon your best chance would be to use totally opaque muddy water, but that kinda defeats your purpose.
In an oversimplified explanation, what's going on with neotenes is a decoupling of the normal association between sexual maturation and metamorphosis. Both are mediated in part by thyroxine, with the endocrinological changes initiated at metamorphosis paving the way for gonadal maturation. In neotenes the ability of tissues other than the gonads to respond to thyroxine is lost (usually by deactivation of one or more genes by any of a zillion possible mutations), and sexual maturation occurs at about the same age, only without metamorphosing. Some Ambystoma species (and populations of others) are obligatorily neotenic and will not metamorphose no matter what treatments you apply, whereas many populations of a number of species are facultatively neotenic -- they will remain as larvae as long as aquatic conditions are good, and may breed as larvae (even with a metamorphosed animal as the other partner), yet will transform if conditions deteriorate. There are also a number of vernal pond-breeding species (including A. californiense) where neoteny has never been documented.
If you want to keep a big larva neotenic, my suggestion would be to hassle it as little as possible during collection and transport, and try to get it feeding immediately as a captive. "Stress" is a trigger, and the less of that, the better is the chance of maintaining a lunker. I reckon your best chance would be to use totally opaque muddy water, but that kinda defeats your purpose.
Re: SoCal desperation herping 1
I'll see if anybody notices this
and take it from there if interest exists. These are larval and metamorphosing Ambystoma californiense which I can compare to A. mavortium.
and take it from there if interest exists. These are larval and metamorphosing Ambystoma californiense which I can compare to A. mavortium.
-
- Posts: 2288
- Joined: June 7th, 2010, 9:52 pm
- Location: Amarillo, Texas
Re: SoCal desperation herping 1
thanks for the advice! if I get the chance I will. I reckon I can do semi-opaque pretty easily.If you want to keep a big larva neotenic, my suggestion would be to hassle it as little as possible during collection and transport, and try to get it feeding immediately as a captive. "Stress" is a trigger, and the less of that, the better is the chance of maintaining a lunker. I reckon your best chance would be to use totally opaque muddy water, but that kinda defeats your purpose.
Interesting photo; did the one metamorphosing lose a digit or two? one of his feet looks shy some toes
Re: SoCal desperation herping 1
That's just the photo angle -- larvae are pretty sloppy with their legs and feet, too.