Skinks from Indonesia
Posted: Fri Jan 25, 2013 10:23 pm
I tried to figure out a way to add my thoughts about the Indonesian/Merauke/Iran Jaya debate on another thread without writing a three page paper that no one would read anyway. I couldn't really come up with a concise post, so I decided to ramble on about it over here instead. No one will probably read it here either, but at least I can get it out without cluttering up the main forums.
I think it is important to remember that the "ID" issues that continue to come up over and over again are actually limited to three groups of skinks. We don't have issues identifying skinks in Australia, with the occasional exception being T.s.s. and T.s.i. The ranges of these two subspecies overlap in an integrade zone, so naturally occurring integrades occur, and these animals are usually the ones in question. Other than that, it is really quite easy to distinguish the difference between all of the Australian species and sub-species.
Unfortunately, it is also common to see Australian scincoides mis-identified as skinks from Indonesia, and vice-versa, but the truth is that most people with some experience can easily tell the difference between these two groups when looking at a "pure" specimen from either group IN PERSON. It can be more difficult from pictures at times, but should be pretty obvious with an examination in the flesh. On top of that, the origins of these two groups are completely separate. It is not nearly as hard to keep straight if a skink came from Australia or from Indonesia as it can be to know what PART of Indonesia an animal came from. The only issues come up over skinks outside of Australia that do not have know full histories. Again, it is still fairly easy to distinguish the two groups even when the history is not known as long as you are not looking at a hybrid. In fact, it is probably fairly safe to identify an animal as a hybrid if it is NOT easy to tell in person if it is from Australia or Indonesia.
I think the point I am trying to make is that the only skinks that really cause any confusion are those that we feel need to fall into one of these three categories:
Indonesian
Merauke
Irian Jaya
I went back and re-read a lot of information on these skinks, and was actually surprised to see how much IS known about the three groups. There a concrete scientific reasons for why these skinks are being classified the way they are currently. While there is never 100% agreement on taxonomy, there really is a fairly strong consensus among the scientific community that T.g.g. and T.g.e. have significant enough differences to be classified as separate sub-species. It is also pretty well established that there is a group of skinks that are commonly referred to as "Irian Jayas" that exist within the range of T.g.e. that are different enough to eventually be classified as an additional sub-species. The problem is, not nearly enough research has been done to be able to set the equivalent of a "breed standard" used in the dog and cat world for Irian Jayas. Until enough data is collected to be able to clearly define what an Irian Jaya is, it will not receive sub-species status.
Currrently, there is not even universal agreement on what SPECIES Irian Jayas are, only the recognition that they appear to clearly exhibit traits of both scincoides and gigas. Based on overall appearance, most keepers and dealers tend to identify I.J.'s as a sub-species of scincoides, however based on scalation traits, Dr. Glenn Shea, who may be the most respected Tiliqua researcher in the world, came to the conclusion in 1992 that this group of skinks should be described as T. gigas evanescens. My impression is that most of the scientific community agrees with this assessment. I am vastly unqualified to offer an opinion based on anything other than the fact that I would tend to give more credibility to the likes of Dr. Shea than those like myself who have a much more superficial relationship with the Genus.
As far as what goes on here on the forum, I think we have gotten away from the true science of identification. Many of us have kind of become "burned out" on the constant debate (although usually friendly). We tend to add and subtract things from our own definitions of each species/sub-species over time based on things we see in pictures throughout the years. By doing that we frequently overlook clear scientific differences between the groups. There really should never be a debate about whether a skink is an indo or a merauke because there are some very clear differences between these two skinks that are easy to recognize. For example, here are a few characteristics unique to T. gigas evanescens:
- They have no primary temporal scale.
- The last supralabial scale and lower secondary temporal scale is paired, resulting it five scales between the lip and the parietal
- They have two supraoculars in contact with the frontal
definitions:
primary temporal - one large scale on the center of the temple
secondary temporal - a scale in the second row of scales behind the eye
supralabial - scales covering the upper lip
supraocular - the row of scales immediately above the eye, "eye-lid" scales
Here is a picture from page 184 of the Bluey Bible that shows the difference in scalation between an indo (on the left) and a merauke (on the right):
When we ID meraukes on the forum, when was the last time these items were considered? We get hung up on color/pattern etc., and forget that there are sometimes very easy ways to know for sure. I could go on for quite awhile, but I know that no one has probably read even this far, so I'll stop. Just sayin', IDing these skinks probably shouldn't be as hard as we make it. There is a ton more that I would like to say, especially about IJ's, but I'm falling asleep.
All of the information I am stating in this post can be found in the "Bluey Bible" which is formally, Blue Tongued Skinks, Contributions to Tiliqua and Cyclodomorphus, edited by Robert Hitz, Glenn Shea, Andree Hauschild, Klaus Henle & Heiko Werning. I am not claiming credit for anything offered here. I just feel that this information should be remembered every time we attempt to identify a skink on the forum.
I think it is important to remember that the "ID" issues that continue to come up over and over again are actually limited to three groups of skinks. We don't have issues identifying skinks in Australia, with the occasional exception being T.s.s. and T.s.i. The ranges of these two subspecies overlap in an integrade zone, so naturally occurring integrades occur, and these animals are usually the ones in question. Other than that, it is really quite easy to distinguish the difference between all of the Australian species and sub-species.
Unfortunately, it is also common to see Australian scincoides mis-identified as skinks from Indonesia, and vice-versa, but the truth is that most people with some experience can easily tell the difference between these two groups when looking at a "pure" specimen from either group IN PERSON. It can be more difficult from pictures at times, but should be pretty obvious with an examination in the flesh. On top of that, the origins of these two groups are completely separate. It is not nearly as hard to keep straight if a skink came from Australia or from Indonesia as it can be to know what PART of Indonesia an animal came from. The only issues come up over skinks outside of Australia that do not have know full histories. Again, it is still fairly easy to distinguish the two groups even when the history is not known as long as you are not looking at a hybrid. In fact, it is probably fairly safe to identify an animal as a hybrid if it is NOT easy to tell in person if it is from Australia or Indonesia.
I think the point I am trying to make is that the only skinks that really cause any confusion are those that we feel need to fall into one of these three categories:
Indonesian
Merauke
Irian Jaya
I went back and re-read a lot of information on these skinks, and was actually surprised to see how much IS known about the three groups. There a concrete scientific reasons for why these skinks are being classified the way they are currently. While there is never 100% agreement on taxonomy, there really is a fairly strong consensus among the scientific community that T.g.g. and T.g.e. have significant enough differences to be classified as separate sub-species. It is also pretty well established that there is a group of skinks that are commonly referred to as "Irian Jayas" that exist within the range of T.g.e. that are different enough to eventually be classified as an additional sub-species. The problem is, not nearly enough research has been done to be able to set the equivalent of a "breed standard" used in the dog and cat world for Irian Jayas. Until enough data is collected to be able to clearly define what an Irian Jaya is, it will not receive sub-species status.
Currrently, there is not even universal agreement on what SPECIES Irian Jayas are, only the recognition that they appear to clearly exhibit traits of both scincoides and gigas. Based on overall appearance, most keepers and dealers tend to identify I.J.'s as a sub-species of scincoides, however based on scalation traits, Dr. Glenn Shea, who may be the most respected Tiliqua researcher in the world, came to the conclusion in 1992 that this group of skinks should be described as T. gigas evanescens. My impression is that most of the scientific community agrees with this assessment. I am vastly unqualified to offer an opinion based on anything other than the fact that I would tend to give more credibility to the likes of Dr. Shea than those like myself who have a much more superficial relationship with the Genus.
As far as what goes on here on the forum, I think we have gotten away from the true science of identification. Many of us have kind of become "burned out" on the constant debate (although usually friendly). We tend to add and subtract things from our own definitions of each species/sub-species over time based on things we see in pictures throughout the years. By doing that we frequently overlook clear scientific differences between the groups. There really should never be a debate about whether a skink is an indo or a merauke because there are some very clear differences between these two skinks that are easy to recognize. For example, here are a few characteristics unique to T. gigas evanescens:
- They have no primary temporal scale.
- The last supralabial scale and lower secondary temporal scale is paired, resulting it five scales between the lip and the parietal
- They have two supraoculars in contact with the frontal
definitions:
primary temporal - one large scale on the center of the temple
secondary temporal - a scale in the second row of scales behind the eye
supralabial - scales covering the upper lip
supraocular - the row of scales immediately above the eye, "eye-lid" scales
Here is a picture from page 184 of the Bluey Bible that shows the difference in scalation between an indo (on the left) and a merauke (on the right):
When we ID meraukes on the forum, when was the last time these items were considered? We get hung up on color/pattern etc., and forget that there are sometimes very easy ways to know for sure. I could go on for quite awhile, but I know that no one has probably read even this far, so I'll stop. Just sayin', IDing these skinks probably shouldn't be as hard as we make it. There is a ton more that I would like to say, especially about IJ's, but I'm falling asleep.
All of the information I am stating in this post can be found in the "Bluey Bible" which is formally, Blue Tongued Skinks, Contributions to Tiliqua and Cyclodomorphus, edited by Robert Hitz, Glenn Shea, Andree Hauschild, Klaus Henle & Heiko Werning. I am not claiming credit for anything offered here. I just feel that this information should be remembered every time we attempt to identify a skink on the forum.