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Post by wollastoni on Jun 5, 2015 16:50:44 GMT
WOW ! There is a 161mm Titanus giganteus for sale on Ebay in the TOP INSECT AUCTIONS . Are such giant common ? What is the record size of Titanus giganteus ? This seller always get some very impressive Coleoptera for sale, he must pay very well his suppliers !   -------------- MANY TITANUS GIGANTEUS FOR SALE : Click here
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Post by trehopr1 on Jun 5, 2015 19:18:00 GMT
Very impressive specimen which will garner a LOT of attention. But, not the biggest as yet collected. The largest known and reliably measured specimen was a 16.7 cm. male specimen collected in French Guiana by a entomologist named Patrick Bleuzen. That measurement was made after it died and dried out . It was actually slightly larger than that while still alive !
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Post by africaone on Jun 5, 2015 21:20:45 GMT
I really doubt that a record size may be found on eBay. Such dealer have private Customer and anyway such "biggest" specimen can be easily sold at very high price without risk of bidding.
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Post by albatus on Jun 5, 2015 21:23:55 GMT
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Post by africaone on Jun 5, 2015 21:38:06 GMT
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Post by trehopr1 on Jun 5, 2015 22:38:22 GMT
Albatus, I don't know where that photo comes from or why the measuring device does not seem to be better lined up with the specimens body. It suggests (via the numerical highlights) a total body length of 16.9 cm however, that just does not seem accurate. Looking at the "inches" side of the ruler it does exceed 6 inches (15.0 cm). And perhaps something closer to 15.7 or 15.9. Anything beyond that seems guesswork. It's just hard to tell by that particular photo.
Another consideration is that the specimen shown is still fresh and has not had time to shrink a little as it dries out. Which is what happened to the record size specimen aforementioned in my above post. I'm not saying it is not possible to come up with another giant to MATCH the record setter OR even exceed it. But, generally speaking outsize specimens like the 16.7 on record are at the EXTREME size range of the species as is so far known. Anything larger would certainly be EXCEEDINGLY rare in nature and would be a one in a million find !
Also, keep in mind that unscrupulous dealers have been known to "toy" with the larger specimens to exort more money out of them. Every mm. can add $100 or more to the specimen cost. So, if someone can "stretch" a specimen a little and add 3 or 4 mm that could add substantially to the end cost. BEWARE of any high end purchases you make on this species of beetle. Don't purchase sight unseen ! See the real deal for yourself and determine first that it has not been "tinkered with" BEFORE the cash leaves pocket.
The same needs to be said about any outsize examples of Macrodontia cervicornis. If it's reported as being MORE than 16.6+ than again see it for yourself and make your determinations. I love hearing about potential new record size specimens. But, I loathe questionable photo's, inaccurate measurement methods, and especially ARTIFICIALLY created "stretched" examples....
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Post by Paul K on Jun 5, 2015 23:16:53 GMT
I don't know about you trehopr1 , but I can clearly see 16.9 cm on the ruler. I am not sure how to determinate if the specimen is dry or fresh but it looks a bit stretched .
Paul
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Post by trehopr1 on Jun 6, 2015 0:49:22 GMT
Paul K, I too see the blue numerical highlight proclaiming 16.9 but, I don't see the hash marks on the ruler lining up properly. If you look to the right side of the ruler where "O" is than you will see that it is lined up with the the tip of the tarsal claw on the front foot. What about the mandibles? There is a metal edge on that side touching the mandibles but, how many millimeters are between the mandibles tip AND the tip of the tarsal claw where the "O" on the ruler is located?
Another point in question is on the left side. Looking at the photograph upside down and carefully counting the hash marks AFTER 15cm. I can only count 7 mm. to the edge of the elytra. So therefore, the specimen only measures a total of 15.7 cm from where the "O" starts on the ruler to the edge of the elytra --- not of coarse taking into consideration the millimeters of space seemingly un-measured between the mandible tip and front tarsal claw where the "O" is located.
Now give or take 5 mm. to cover the mandibles I feel a far more accurate measurement is closer to 15.7+.5= 16.2cm total
If 5mm is being too generous than lets say 4mm. That then makes it 16.1mm total
It's still an exceptional example having reached that size but, not record as the photograph purports. And it could still be fresh in the photo so it would almost certainly lose some millimeters to drying out. I am of coarse open to any other reasonable insights any other forum members might have.
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Post by trehopr1 on Jun 6, 2015 1:01:34 GMT
Another thing to point out is that good verifications should always have 2 or 3 photo's for comparison sake.
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Post by Paul K on Jun 6, 2015 2:04:35 GMT
I am afraid you are wrong . On this picture this ruler and it is not regular ruler ( It is caliper ruler) shows that this Titanus has 16.9 cm and I am not looking at blue mark but the ruler it self.
Another explanation of this if it is not new record that could be a photo shop picture. One photo taken of the ruler and then another photo of Titanus zoomed and fixed in . It is very easy to do with today's photo softwares.
Therefore I agree with you there should be few more photos to confirm .
Paul
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Post by Paul K on Jun 6, 2015 2:12:39 GMT
Again looking at the back of the specimen we could see a shadow and a bit of brown coloured reflection on the ruler -caliper , so the photo looks real to me.
Paul
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Post by trehopr1 on Jun 6, 2015 2:52:49 GMT
Well Paul K I've looked again at the photo and I still don' t see what it is you do see. So I guess the ridiculous ruler placed in the photo is leading to more questions than answers. I still believe my hypothesis is correct. And again I say multiple photographs taken at different angles produce the best results. But, you did make a very valid and interesting note yourself; that the photo could be photoshopped. I never thought of that angle. Well, until I hear differently about any new measurement records being set I'm comfortable with the present record of Titanus were it officially is --- 16.7 cm
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Post by cabintom on Jun 6, 2015 3:13:06 GMT
Well Paul K I've looked again at the photo and I still don' t see what it is you do see. So I guess the ridiculous ruler placed in the photo is leading to more questions than answers.  en.wikipedia.org/wiki/Vernier_scalesee also en.wikipedia.org/wiki/Calipers#Inside_caliper under "Vernier Caliper" Just trying to highlight how this measurement device works. (In red, I've noted the offset, it's equal on both the large scale and the vernier scale.) Also, this particular image would have been difficult to photoshop, given the highlights on the scale and insect, and shadows beneath them both. |
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Post by trehopr1 on Jun 6, 2015 3:21:45 GMT
This size topic also brings to mind a similar topic brought up some time back on the InsectNet forum. That topic concerned Thysania agrippina. Some collectors spread their specimens properly (at the perpendicular) and then measure tip to tip. Others have spread theirs in more of a resting position (as in nature); with the leading edge of the forewings (costa) forming a straight line across --- and then measuring tip to tip. The 2nd method results in an ambiguous or erroneous measurement.
The Guinness book of world records has stated in the past that the largest known verifiably measured Thysania is a female taken in 1934. It was in the collection of one John G. Powers of Ontario Canada. Don't know if you or any one else know this fellow or if he still has his phenomenal specimen. But, I for one would love to see a photo of this giant and more importantly I'd like to see how it was spread. Hopefully not in an "at rest" position. The article also states that the specimen has a wingspan of 308mm.
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Post by trehopr1 on Jun 6, 2015 3:46:04 GMT
Thankyou cabintom for your imput. I've never seen or used a ruler of this type. So I have two guesses to make here. That this photo may well be of the record 16.7 cm. PRIOR to it drying out. Or it is of yet another beast ( which looks fairly fresh ) in the photo which has not as yet dried out. Also, of note is that there does seem to be a separation somewhat between the pronotum and the wing covers. Perhaps, only 2-3 mm but it's there. As such, shrinkage would conceivably tie it with the record or put it slightly under it. What a horse !
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