Sharpening the Blade -- Southeastern Five-lined Skink Range

3/18/2024

Southeastern Five-lined Skink | © Ty Smith

Background

Unfortunately, Plestiodon skinks are tragically misunderstood and misidentified often in Virginia and other states. As I have mentioned in this article here, these skinks are very tricky to ID and one trait alone is not a good way to ID these guys. Most people studying these animals are using genetics to ID these species and are then noting these subtle differences and how accurate they are in their papers. I have been paying close attention to these species for over a decade, as I noticed as a young teen chasing and catching these lizards that my field guides were not 100% accurate on these species... Now, modern field guides are getting much better, but IDing these lizards goes much deeper than labial counts. I have received immense pushback for even suggesting that supralabial scales are a very poor way to identify these animals, as many old school herpers still revier these counts. I don't understand why, when several papers have shown that this trait is only 60-80% accurate (likely a fluctuation in frequency tied to geographic variation) and I can show you individual Common and Southeasterns that I and others have found with 4 and 5 supralabials depending on opposite sides of their heads. I do know several herpers though that were very skeptical of what I was saying, and now they strongly agree that you can accurately judge a male Broadhead from size and build alone, and Southeastern Five-lined Skinks from dorsal scale counts and male head structure. Peterson's Field Guide has added this in their 2016 edition, but better late than never guys! Haha

Some herpers could never be birder though, as many herpers will call Broadheads and Common Five-lined Skinks identical, when the many of the differences are very similar to Canada vs Cackling Geese. But you know what, that is perfectly fine. We all are different, and some people have incredible attention to detail in some areas but not others. Think how a musician can right a beautiful piece, but may be color blind. They are still a talented artist, just not in the same way a painter would be. Some fishermen can tell the difference between different sunfish (and can even tell a hybrid accurately), while others see them all as "Bluegill" unless they have a red spot on their ear; then they are Redear Sunfish. Sometimes training and seeing hundreds of specimens helps, but it is nearly impossible to teach this skill.

So, after both of us being involved with the discovery of Southeastern Five-lined Skinks in Galveston, Chris Harrison sent me a message. He was writing the paper and trying to figure out how far out this population was from the nearest known population, and noticed something was off. There were three Southeastern Five-lined Skink records west of the Mississippi River, and all were museum records. Upon checking these records, they were all misidentified. They were not even odd individuals, just whoever logged them misidentified or mislabeled them. That drew me to the Virginia map. There are dozens of outlier records in northern and western Virginia, that there is no iNat data for these species in these areas. Unfortunately, in my opinion, without a photo voucher or museum specimen, we can only use these records as circumstantial evidence.

Furthermore, many of the VHS records have no photo or museum records attached, and some of the ones that do are misidentified as well. For example, the Spotsylvania County record from the VHS spring survey is a good example (paper here). The photo voucher is shown to the right, and you can see this middle row of post-ventral scales are only slightly enlarged; but the eyes trick one into seeing them as all equal sizes. This means that if you don't take your time when looking, you could quickly judge it as either. When one separates and compares the scales side-by-side, they can see they are clearly enlarged, and this is a Common. The enlarged head and facial pattern (see the paper) also point to this being a Common Five-lined Skink.

Skink in question from the 2022 VHS Spring Survey at Lake Anna | © Matthew Neff

Common Five-lined Skink post ventral comparison. Note the center scale is ~1.5 times the size with the next row on either side | © Ty Smith

Southeastern Five-lined Skink post ventral comparison. Note the center scale is close to equal in size with the next row on either side | © Ty Smith

To make it easier for the less trained eye, I drew lines on the scales (using Canva) in the photos and then copied them in the white circle (I did have to tilt the lines, but I did not change the size and you can measure with a piece of paper and pencil to check). You may see how it is like one of those test where they put two lines side by side and offset them and ask which is bigger, and our eyes struggle to judge them accurately. To be fair, I did this with my own photos of a Common and Southeastern Five-lined Skink, and as you can see this Lake Anna skink definitely favors the Common Five-lined Skink.

Now, I bring this all up not to say anything negative about Matthew Neff, as I have nothing against him nor a reason to personally pursue him. This skink is just a great example of how these two can easily be misidentified when focusing on one trait. Other misidentified skinks I had found were not very tricky individuals, and maybe mislabeling was involved. This just shows the power of a photo or specimen voucher. How many records were similarly misidentified? We don't know because we can't see all of the photos. VHS may have these photos locked away in a digital archive somewhere, but most of what I have seen are all written records, many of which not explaining how they were IDed.

My 2022 "Counties of Interest Map" for Southeastern Five-lined Skinks

2022 Known and Predicted Range Map or "Green Map" for Southeastern Five-lined Skink

All of this had prompted me to put these maps together above, to try to draw conclusions from. All of our maps are speculative, yet based in trends and data. For example, if a species has been found in two counties, but never found in the one between, as long as the county has habitat, we can speculate that they are there. Well, it has been two years, and it is time for me to revisit this. We have more iNat records, more VHS records, and I surprised myself here recently with some new records in counties not previously suspected to have these skinks.

Updates!

So, I moved to Buckingham County in 2022. Last summer, I found dozens of Common Five-lined Skinks, as predicted, that said my property backs up to a pine stand, and the overall area is fairly dry and elevated. I had noted that our property is actually fairly good habitat for Southeasterns. Then, one day last July, I flipped a juvenile skink that looked to be a Southeastern Five-lined Skink due to its thin, broken lines. The skink was living under my chicken coop, and I saw it twice more, but was never able to catch it or get photos in the brief encounters.

The first Buckingham County record Southeastern Five-lined Skink | © Ty Smith

In late October, I flipped a skink under a board that appeared to be a non-breeding Male, but it too eluded me. I stayed skeptical, as I have a healthy Common Five-lined Skink population, and two "oddballs" that I saw for less than two seconds at a time is not enough data for me to form a idea on and be any kind of confident (or people to take me serious). So, last week (March 15, 2024) I was so astounded to finally "get lucky". I flipped a board, that will hopefully soon be part of a raised bed, and there was a non-breeding male Southeastern Five-lined Skink which was fairly chilled from the night air. The observation is here.

So, this means we can confirm this species is present in Buckingham County. Which wildly changes our map on the "northern frontier" of this species range. That said VHS has since added records as have others on iNat. So, as of March 18, 2024, this map shows all of the counties for which we have records. Misidentified VHS records are included, and I will go deeper into that in a bit.

iNaturalist and Virginia Herpetological Society (VHS) Records

Based on this new data, my doubts are now somewhat cleared up for Cumberland and Powhatan Counties, and we can now include Buckingham in as well. I noticed I left Charles City Counties off of the original "known and predicted range maps" or "green maps" (the maps we use for all of our species profiles) and that was a complete oversight on my part. I believe that the habitat and just lack of people searching means they are almost certainly there. Henrico though is a tough one, and I just want more data. They very well may be here, and I feel they probably are, but the lack of iNat records in an area as heavily populated as this concerns me. Greensville and Southampton almost certainly has this species. I would say even if these VHS records are misidentified, the only reason we lack iNat observations are because very few people live down there... As for most of the other VHS only counties, I really want to see more data. I do not believe the Loudon, Fairfax (more on these later), or Buchanan records were identified correctly, but I would love to be proven wrong.

So, Shenandoah and Page are interesting. This record here is pretty clearly a Southeastern Five-lined Skink from Shenandoah. I am quite skeptical of these types of "one-off" observations, but it isn't so one off. Joe Mitchell documented this species in Page County at the site that this one was found at, just across the county line. If you are not familiar with Joe Mitchell, he is regarded as the "Godfather of Virginia Herpetology" and he carried out the "Atlas of Amphibian and Reptiles in Virginia" or as Virginia herpers refer to it, "The Mitchell Atlas" which was published in 1999.

Joe Mitchell did a lot of good field work, and is well respected amongst herpetologists in our state. The only downside to using Joe Mitchell's atlas is he didn't add a lot of photos, so we can't go back and revarify his records. While I do not doubt his capabilities, everyone makes mistakes. When you are creating thousands of data points and many data points are submitted by, "scientists and amature naturalists" (in other words not Joe Mitchell), a mistake can easily happen. So, I have to take this as circumstantial evidence for now, and use other data to speculate further.

Joe Mitchell also reported the species in Craig, which would not surprise me one bit, but his team did report the Loudoun and Fairfax records as well. I have heard rumors of a museum specimen from the page site as well, which I am told is "good for inexpectatus" that I would love to see. So, I will include Shenandoah and Page on the known and predicted range maps due to the stacking of the photo and the Mitchell record. Why are Southeastern Five-lined Skinks here? Well, the habitat is perfect, so maybe they are natural holdbacks from a past time period where they were more widespread, or ended up there by anthropomorphic means. If the former, maybe some of these old VHS records are holdouts that are now gone as well. Maybe the Bedford population we found are also holdouts, but with such sparse data in other local counties, I feel they are very likely conjoined, even if it is only by a "finger" through Charlotte and Campbell Counties.

iNaturalist observation map for species in the genus Plestiodon. Note how well covered the county is with data points.

As far as Loudoun and Fairfax, I do not see how these species could be present Fairfax or eastern Loudoun due to the coverage of Plestiodon records, urban sprawl, and lack of Southeastern Five-lined Skink records we see on iNaturalist. I could however see a small population "flying under the radar" in western Loudoun County, though I think it is fairly unlikely. As for these records, who knows what happened. They could have been misidentified, inaccurately plotted, transplants from the plant or lumber trade, or maybe they were there and are now extirpated. Either way, there is no current evidence of a breeding population in either county that I have seen.

Where Do I Think They Are?

It is not easy to build a "known and predicted range map". The issue comes down to how accurate the map is. In addition to straight forward evidence, there are places where we can be rather sure a species is present, but we don't have the data, places we have data but we are rather sure they aren't there, and straight-up toss-ups. How we handle these descressions is completely up to the map maker, and the accuracy of such maps is full opinion until new data comes forth. For example, there is no records of Southeastern Five-lined Skinks in Greensville County, but there is plenty of habitat and they are found in most adjacent counties, so do we expect them here? In my opinion yes. There are records from Lunenburg, Prince Edward, and Mecklenburg Counties but none in neighboring Charlotte, so are they there? Maybe. I feel they are due to there being plenty of habitat, lack of study, and several specimens farther west in Bedford; but just because I believe they are there does not mean that they aren't and the Bedford populations aren't isolated. What about Fairfax, where I have shed my doubts already? Do we count it because there is a weird record that we can question strongly? I say no... That is my opinion though. You can disagree, and that is fine. We can knit-pick details all day and speculate and who knows who is right in the end. That said, if you strongly disagree with me, want to prove me wrong, or are just curious about your area, go out in dry, piney areas of your county and photograph as many skinks as possible from as many angles as possible. I don't want these maps to be more of opinion than data (as they kinda are now in some places due to the lack of data). I want to get this right. I have no reason to want them to exist in one county but not others. I want the map above to be all deep red, and not so much light orange. It is impossible to prove something doesn't exist with data alone (logic is important for this), but we can at least prove something is there with a bit of work.

So, to turn this map above into a "green map" I need to explain what we are seeing on this map. The deep red is easily on the "predicted and known range" map because it is the known range. The dark orange is pretty much the areas were we have some good data to suggest they are there. Why is Shenandoah not red? Well, while I feel it is important to include, I cannot prove this one photo record was from where it is said to be, and without seeing other specimens, I feel saying it is "known" is a bit too much. I just feel this location is one good record away from being red. Light orange is areas that I am just not sure about, and it is a wide spectrum of feelings. It would blow my mind if no one finds a Southeastern Five-lined Skink in Charlotte County in my life time as much as it would blow my mind if someone were to find one in Buchanan County in my lifetime. Some of the spurs of the peninsulas are the most difficult for me. Sure, they could be there, but why do we see multiple iNat records in Lancaster, but none in Northumberland or the other counties on the northern neck? We see this weird trend where records are on the tips of the peninsulas, but not the rest of it, and this is not the only species that I have noticed this for. I am not sure if it is lack of data or what, but for now I am leaving them off of the green map, but I am full suspecting someone to find some somewhere in one or more of these counties to change my thoughts in the future. It is a big question mark, and I would rather not speculate to much without more data.

The "Green Map"

So, why did I settle on predicting them in Craig, Pittsylvania, and Halifax Counties? Simply put, it is solely due to the presents of Southeastern Crowned Snakes. The same site we had this species in Bedford, we had several Southeastern Crowned Snakes. The site in Pittsylvania where we have had Southeastern Crowned Snakes, was perfect habitat and only a few miles away from the Bedford sites, but we found no non-snake lizards. These snakes require a niche habitat in this area, in which Southeastern Five-lined Skinks thrive. The Virginia Tech team in Craig County that are looking for Northern Pine Snakes found a single Southeastern Crowned Snake in 2022 while digging trenches for their drift fence. This information paired with Joe Mitchell's reports makes me feel they are likely there.

So, what do you think of my newest rendition of this map? I hope you enjoyed some of the insight to my thought process for making these maps. Remember, I can always overlook a county too, so if you see a county that I missed that you know there are photo records for on any of our maps, send us an email. I get these emails occasionally, and usually I just missed it by accident. These maps are incredibly fluid as new information comes in, and we revise old information. I hope one day, in my lifetime, we will see far more accurate maps. If you want to help us "sharpen the blade" for this species, post your skinks on iNat or visit our "Herp ID Help" tab at the top, and submit them in our form for ID. We will be waiting!

Works Cited

Michell, J. C. (1999). In Atlas of Amphibians and Reptiles in Virginia.

Neff, M. (2019). Virginia Herpetological Society 2018 Annual Spring Survey Lake Anna State Park in Spotsylvania County, Virginia. Catesbeiana, 39(2).