Split/Extra Scutes

[motero]

I have a freezer lined with heat watt tape and a Helix controller. Non of my thermometers register any difference next to the tape vrs middle of the freezer. But the out side row of eggs closest to the tape on each side, have been consistently hatching first and hold more split scutes than the rest of the clutch. I would say yes temperature is a factor. But in my case the temperature difference is less than half a degree.

<<The two babies in my avatar, are reaching 8 - 10 inches and look female, But they all do at that point, we will see.
I raised a group of leopards from hatchlings the split scutes turned out female, the regulars turned out male except one.

Just my observations.
Torts are Fun.

 

[Markw84]

Ok, now the confusion kicks in.
It's said higher temps produce females with potential splits etc and lower temps produce males. Above is a male splitty.
Does this mean an egg is layed,then at some point the embryo develops and the temp at that/a particular stage dictates the sex to be. (let's say in this instance it was a low temp at the critical sexing stage to produce a male), then after that stage and for duration of incubation the temps got on the high side. Is this how a male splitty would happen?

I can't quote exact sources, but I have had several discussions about this over the past 25 years. It seems the sex determination is more dependent upon the temperatures in the latter half of the second trimester of development. To avoid split scutes and possible increases in deformities we would keep temps in the mid range and then raise at about 1/2 through expected incubation times to the " female" temps. I kept there until pipping. It seemed to reduce split scutes and still got females. Theorized the mechanism that sets the scute pattern happens sooner in the incubation process. That's not doable with clutches at various stages in the same incubator and haven't heard much on this since those days I was much more avidly exploring this so I don't do that much anymore. Also became less concerned about sexing my hatchlings. I do plan on going back to that method with my Burmese so this is great it has come up

Would love to hear more thoughts on this...

 

[Anyfoot]

I can't quote exact sources, but I have had several discussions about this over the past 25 years. It seems the sex determination is more dependent upon the temperatures in the latter half of the second trimester of development. To avoid split scutes and possible increases in deformities we would keep temps in the mid range and then raise at about 1/2 through expected incubation times to the " female" temps. I kept there until pipping. It seemed to reduce split scutes and still got females. Theorized the mechanism that sets the scute pattern happens sooner in the incubation process. That's not doable with clutches at various stages in the same incubator and haven't heard much on this since those days I was much more avidly exploring this so I don't do that much anymore. Also became less concerned about sexing my hatchlings. I do plan on going back to that method with my Burmese so this is great it has come up

Would love to hear more thoughts on this...

Still a lot to learn here, but one of the things that puzzles me is this.
In the wild do nests stay at a stable temp,I'm assuming not, especially at night, or do they?

 

[bouaboua]

This is our prefect miss scute Hermanni, and it is our very first hatchling.....

 

[Markw84]

Still a lot to learn here, but one of the things that puzzles me is this.
In the wild do nests stay at a stable temp,I'm assuming not, especially at night, or do they?

The friendly debate back then between us was whether you needed to let incubation temps fluctuate to simulate day/night differences, or if a steady temp would reduce hatch rates. Also the temps had to fluctuate with weather conditions. A sulcate buries a deep nest by digging a body pit first to help minimize fluctuations, it seems. But most tortoises have much shallower nests. One of our group became the first ever to successfully breed and hatch ploughshare tortoises, so had pretty good success. He at that time like fluctuating incubation temps believing higher hatch rates, and better hatchling survival.

I also know of experiments where sliders and painted turtles were compared at stable vs fluctuated temps in incubation. Groups were incubated at 28.5 constant, and other groups at fluctuating temps from 3 above to 3 below 28.5C. This was meant to simulate the natural fluctuations in a wild nest. The fluctuating temps produced more females, but interestingly also produce larger, more robust hatchlings with a longer incubation time.

I know studies of sea turtle nests actually showed very little fluctuation in temps at nest depth by actual measurement, even over the course of rainy days. But again, talking about a turtle that lays in deep nests by digging body pit first.

I'm sure by now someone in the field has had to stick a probe in some natural nests of some tortoises we deal with. It would be great to get some actual data on this. And how does diapause fit into this, then???

 

[Anyfoot]

So thinking logically, there has to be eggs incubated at different temps to acquire different sexes to keep the species cycle going.
If we assumed in the wild that temps in the nest were stable throughout incubation this would mean that nesting positional sites would dictate temps. For example 3 nests, 1 in the open, 1 in dappled shade and 1 in deep shade, all 3 would have different temps regardless of the air temp. This would be one way of nature covering the temp ranges needed for sexes. I can't see this option as a possibility purely because of night temp drops.

If we assume temps vary through day, night, and generally through seasons in the nests this would also cover the temp ranges required to provide both sexes. This sounds more viable to me. This must mean that temp fluctuation is natural.

I was told there are also splitties found naturally in the wild. If temp fluctuation at the higher end ALONE causes splitties there surely would be a very high percentage of splitties in the wild if these same temp fluctuations are mother nature's way of maintaining mixed sexes.
So is there another factor aswell as or instead of temps. If the percentage of splitties in the wild is low(I'm assuming it is) there must be another factor other than just temp fluctuation.

Do we know if non splitties and splitties have come from the same nest in the wild?

 

[Scott Hager]

Last year was the first year that I hatched out sulcatas. I used a converted standup Snapple cooler that I've used successfully for countless ball python eggs. I had the temp set to 89 deg with 2 in line Ranco thermostats. There are several small fans mounted inside to circulate the air and prevent hot spots.

As you can see over half of the hatchlings have split or combined scutes. She had 3 clutches and all three had a high percentage of scute abnormalities. I'll recheck everything this year and see if I get the same results from the same pairing. I'm going to change the temp setting to 86 instead of 89. I also held back 4 babies from the first clutch that had the biggest abnormalities. The biggest reason for holding them back was that my wife and kids fell in love with the more unusual shell designs.

 

[mctlong]

F

My fridge incubator has very even heat throughout its whole, so all eggs should be subjected to very similar temperatures, and any variations. I get a few splittys every year, with temperatures typically varying from 84-88 throughout the incubation period. I would note that those that have hatched outdoors in the summer (likely subjected to much higher temperatures, commonly in the low-90s air temp) more commonly have split-scutes, so perhaps this supports the hypothesis that it is a temperature-dependent phenomenon.

It has happened from all of my females roughly equally. I have a split-scute female nearing adulthood that I hope to be producing f2's from next season. Will be curious to see her offspring.

Please keep us posted on the progress this one's offpring! This is fascinating.

Just thinking outloud - We already know that torts exhibit some environmental controlled gene expression. For example, temperature can affect whether they will develop into a male or a female. We also know that, in some animals, environmentally controlled gene expression can be cross-generational. If split scutes are caused by incubation temps, I wonder if the scutes are a result of non-genetic physical malformations in development or if they are the expression of otherwise inactive genes that are triggered by high temps. If latent genes are triggered, we may see cross generational split scutes in hatchlings who were not exposed to the enviro conditions that caused the split scutes of their parents. How cool would that be?!

 

[Pearly]

I've seen split/extra scutes (one of mine has them) but have never seen scutes fused together into a one big scute. Very cool! And I love all your babies around that food. Which btw, you chop it same way I do. Good to see a Fellow Chopper

 

[BrianWI]

The one in the pic at 12 o'clock is really cool looking with the merged scutes. Did u keep him back? Have a recent pic?

 

[Scott Hager]

Here's a picture of the four that I held back taking their morning bath.

 

[mctlong]

Do you plan on selling the one second to the bottom?

 

[Scott Hager]

No I'm planning on holding them back. Hopefully they are female and I'll breed them.

 

[BrianWI]

Do you observe that around extra scutes toward the rear, pyramiding is more apt to occur?

 

[Scott Hager]

Not in particular, but I haven't produced enough of them to make a scientific judgement. If it is a split scute, maybe the smaller size would make pyramiding SEEM more pronounced.

 

[Markw84]

With sulcatas by far the most common is with the rear vertebral scute splitting

 

[Tidgy's Dad]

Would like to hear your experience/opinions from multi clutch hatches. Purely from incubation temps or does genetics play a role? What has been your experience?

I'm sorry, the births i see here ( or to be truthful, the just after births show no splittiies)
i have seen several thousand, but never a splitty.