Gilbert's Dragon?

Discussion in 'Reptile and Amphibian Identification' started by tropicbreeze, Jan 20, 2020.

  1. tropicbreeze

    tropicbreeze Active Member

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    I believe this is Lophognathus gilberti but I'm not sure. It was in a creek and initially I thought it was dead/drowned. Fished it out with a net but it was playing 'possum'. Put it back and it didn't seem in a hurry to leave. Unfortunately the photos aren't the best. It was in the Victoria River District, NT. Any definite ID would be much appreciated, thanks.
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  2. longirostris

    longirostris Active Member

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    Its really difficult to get any clear indication of head markings or ear openings or even any idea of size for that matter from the pictures. To be perfectly honest the first picture looks like a different animal to the second picture which appears more robust perhaps even a gravid female. I could not say with any certainty what the species is other than could be either L. gilberti or perhaps even L. horneri and then again it could even be A. centralis as the second picture shows patterning very similar to animals of this species I have in my collection. If when you picked it up you noticed a whitish strip from the back of the eye to over and around the ear opening then likely gilberti. Although a clear white spot or blemish on the tympanum would mean horneri. If neither of these features were present then a big chance it could be centralis.

    Sorry but that's probably the best I can suggest with the pictures as they are.
     
  3. tropicbreeze

    tropicbreeze Active Member

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    Thanks for the comments Longirostris. They're old photos I'm trying to put labels on. The difference in the photos did strike me as odd, but both were taken at 12:31pm and there was only the one lizard there. Can't recall any markings now other than what's in the photo. For size, there's only the diameter of the net opening, 50 cms. It'll probably remain a mystery but with three possible names.
     
  4. Bluetongue1

    Bluetongue1 APS Veteran APS Veteran

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    I think you can rule out A. centralis. From the photo on the netting it appears evident that the adpressed hind limb would extend to at least as far as the tip of the snout, versus A. centralis in which it reaches only to the eye. It is also well out the known distribution for A. centralis.
     
  5. longirostris

    longirostris Active Member

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    Maybe and maybe not. Sorry Bluetongue but I do not agree with you on this one. Your comment above completely ignores in my view the characteristics of the animal in the second picture which the OP has said he or she believes is of the same animal. Your hindlimb hypothesis may possibly be correct for the animal in the netting in the first picture but I'm pretty sure that the animal in the second picture has chunkier rear upper limbs and not quite as long also. What would you say is the known distribution for A.centralis, who or what field guide are you using to make this comment?? There seems to be some conjecture on this point from the 4 or 5 references and field guides that I have looked at for confirmation of what the actual range for A.centralis actually is. I can tell you for a fact that I have seen this species well to the North and East of where just about every field guide and reference says they occur. I have seen these things at the junction of the Carpentaria and Tablelands Highways right near the Heartbreak Hotel and examined and seen literally hundreds of these at Kiana station which is only a few minutes down the Tablelands Highway. At best the field guides and so called known distribution would have these locations as right on the extreme limit or in some cases outside their so called known distribution yet they're there, I've seen them and examined them myself. I see no reason why the same thing couldn't happen on the western side of their distribution. Whereabouts along the Victoria River are we talking about. Are we just north of Top Springs on the Buntine Highway or are we a hundred or so miles further west. Either way I still don't rule out my comment that the second picture may or may not be A.centralis. I agree that the first picture is more representative of L.gilberti or L.horneri but I am not so sure with the second picture. That's why I made the comment that it could be any of the three species mentioned and I even gave the OP some further hints that may have triggered some recall that could have helped that person and us get a better idea of just exactly what we are looking at in the pictures. By the OP's own admission the picture quality is not great and quite frankly gives very little clues as to narrowing down with any certainty the prospect that the animal in the "2" picture could be any one of the three species I suggested. What I will say that I have already said in my first post responding to this request for ID is that the second picture does not to my mind look like the same animal that is in the first picture. It may very well be but I see some indicators that suggest two different animals, not the least of which is that the animal in the second picture appears far more robust and possibly even gravid particularly when the picture gives several indications that the specimen is female, (smallish head relative to body size, no obvious hemipene bulges around the tail base). This animal is very representative of the female animals I hold in my collection right now from the species A.centralis. The first picture is of a much slenderer and even immature animal that from what I see I would say is either L. gilberti or L. horneri either of the two. I am not convinced that the 2 pictures are of the same animal but I may be very well be wrong on this point as well and what we are looking at is just camera angles and lighting showing the same animal in different poses light etc. In any case I believe I can say with a high degree of certainty what I have already said and that is that what the 2 pictures show is either one or possibly even 2 (probably more likely) of the 3 species I have already mentioned and that it is most unlikely that it would be anything else other than one or 2 of those 3 species.
     
  6. Bluetongue1

    Bluetongue1 APS Veteran APS Veteran

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    My comment on distribution was INCORRECT! Apologies. @longirostris, sorry for the effort put into correcting me. Working from memory I was only thinking of the lower portions of the Victoria River. I should have checked how far it actually stretches inland. So Tropicbreeze’s use of the term “region” covers a lot of territory.
    Aside from that, there was a typo - the comment should have read “outside the...” and not “well out the…” My use of “known distribution” was to indicate that distributions can change as we discover more.

    I do understand the common shortcomings of distribution maps. The distribution data I primarily referred to is in the article: “Diversity in Australia’s tropical savannas: An integrative taxonomic revision of agamid lizards from the genera Amphibolurus and Lophognathus (Lacertilia: Agamidae)”.

    Tropicbreeze seemed very adamant that the two animals are one in the same. So I looked for reasons as to why they appear different.
    · In the photo1 one can see folds of loose skin and flesh either side of its abdomen. As the lizard is lying along a furrow in the net, the remainder of the abdomen would occupy the furrow. In photo2 the water would be supporting the loose skin and flesh, spreading it out to give the impression of a much more robust animal.
    · I am wondering if it is possibly a female that was interrupted during egg laying. That might also help explain why it did not run off, as one would normally have expected.
    · In the photo1 the hind legs are held horizontal and in the same plane as the body. In photo2 the hind legs are angled upwards, with the feet underwater on the bottom of the pond while the knees are in the air and exposed to sunlight.
     
  7. tropicbreeze

    tropicbreeze Active Member

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    The only thing I can add to the discussion is location. It was about -15.44705, 130.03066, give or take a couple of hundred metres along the creek line. Pinkerton Range on Bullo River Station, just outside the Auvergne Station boundary.

    The differences in the two photos is a puzzle. But they were taken within the same minute by the camera's clock. Unfortunately enlarging the photos doesn't help the resolution.

    That's the only explanation I can think of as well for the appearance of the abdomen. When released back into the water it moved to the edge and likely the abdomen was supported by rock just under the surface which made it spread out, as opposed to the way it was in the net.
     
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  8. longirostris

    longirostris Active Member

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    Thanks for the additional locality information which does in all likelihood suggest to me that the chances of the animal/s being A.centralis are now fairly remote if not at all. This location would be likely too far north of their upper limit of the northern section of their range. So I guess you are left with just the two possibilities of either L.gilberti or L.horneri. I agree that the timing of the pictures taken would suggest the same animal also. To me though the animal in the first pic looks a bit like a juvenile where as the second pic looks like a gravid female and again almost identical to my A.centralis female when she was gravid last season. But we have ruled this species out due to range so for me one of the 2 listed.
     
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