Posts Tagged 'tyrannosaurs'

Notes on the taxonomy and identity of Zhuchengtyrannus

After the quick intro to the new taxon, now it’s time to talk in a bit more detail about the bones of Zhuchengtyrannus. All we have is a maxilla and a dentary but that’s actually quite useful. A few ribs and some caudal vertebrae wouldn’t have told us much as these are rather conservative in tyrannosaurs, but happily maxillae are not and have lots of useful and important taxonomic characters in them. It is also worth remembering that pretty much any bone, or even part of one, that is diagnostically different from everything else out there is reasonable to use as the basis for erecting a new taxon (like Brontomerus and various others).

I should of course add, before I go much further, that this is a blog, not a paper. There is more detail and commentary in the actual publication than here in internet land and if you really want to dive in then go read the paper (though again the paper as it stands online is an uncorrected proof, and that has cut off part of the taxonomy stuff!!!). This here is little more (as ever) than a surface discussion of the issues for general consumption and if anything more general than normal as I hope (expect?) that a few more people than normal will be finding the Musings right now as a result of the media coverage.

For those that don’t know their tyrannosaur taxonomy as well as they’d like it’s worth noting that Zhuchengtyrannus is a tyrannosaurine and that puts it in the group of especially large and derived tyrannosaurs and as part of a Late Cretaceous group that was restricted to eastern Asia and North America. We can tell this at least in part because it is a huge theropods from the end Cretaceous of China, but the relatively straight anterior edge of the maxilla supports this, and the shape of the teeth and dentary put it well within the tyrannosaurs in general.

Zhuchengtyrannus teeth. From Hone et al., in press

At this juncture, it’s worth remembering that there are different ways of identifying species, or more specifically, distinguishing them from others. Obviously with a fossil we’re working on a morphological species concept (that is, identifying a species buy it’s anatomy), but more specifically we can separate out differences in different ways. First off we can look for genuinely unique features – a giant tooth in socket 5, only one finger on the hand, a skull twice as long as tall etc. Things that appear in our new species that don’t appear in any others (or at least any other close relatives – stripes are characteristic of tigers since even though other cats are stripey, you’d never confuse the two because of the obvious size differences etc.). Secondly though, you can look for unique combinations of characters. One species may have a long and wide skull, another a short and narrow skull. The characters of ‘long’, ‘short’, ‘wide’ and ‘narrow’ are all in play here, but you could distinguish a possible new species with a clearly distinct combination of ‘long and narrow’ or ‘short and wide’.

So onto Zhuchengtyrannus. This is diagnosed in our paper by two unique characters – a short of shelf on the anterior part of the maxilla and an odd notch in the maxillary fenestra (see figure below). Neither of these does, to our knowledge (or indeed that of the referees or various other colleagues we consulted), turn up in any other tyrannosaur specimen ever. There is also a unique combination of characters to further separate it from other tyrannosaurs in the position of the antorbital fossa and size of the maxillary fenestra.

Drawing of the Zhuchengtyrannus maxilla. The unique shelf is labelled 'S' and the notched fenestra 'mf'. From Hone et al., in press

Although the specimen was not entirely complete when recovered (and sadly the maxilla was later damaged as can be seen from the picture of the maxilla in the previous post) it was initially in very good condition. We have good reason to think therefore that all of these characters are valid ones. The bones were not broken (well they are a bit, but not where the critical characters appear) or distorted or altered and there was no sign of disease or pathologies. This is also not an issue of ontogeny (age-related changes). The animal is easily big enough that it’s hard to credit that it was anything other than an adult, and possibly a large one at that. Moreover, there is a decent literature on both ontogenetic changes in tyrnanosaur skulls and on intraspecific variation. Zhuchengtyrannus exhibits several characters that are normally only seen in adult tyrannosaurs (like the heavy sculpting on the maxilla, more on that later) and the characters we use in our diagnoses are not known to vary either through growth, or within putative populations.

For all of this, lumping taxonomists out there might well not regard this as valid (“To synonymy, and beyond!”). There are those who would still have Tarbosaurus as ‘just’ a species of Tyrannosaurus and I can only suspect they won’t like this much as a result (though I don’t know for sure of course). All I can say is that we are happy with the distinctions, and the referees and other colleagues who have examined the material were too. Taxonomy really does operate at little more than a consensus level and while this can all change, already (from what I have seen and discussed so far) the consensus is that this is a perfectly valid taxon. Of course there’s also a good chance that we will get more material of this species (indeed as noted previously, we may already, even if referral is currently an issue) which will help our cause. Given what bones we currently have, Zhuchengtyrannus seems to be as diagnostic as any other large tyrannosaur and while it could be better (we don’t have that much material), it is sufficient.

Even so, this is only the second tyrannosaurine from China and one that very probably overlaps in time, and space, with Tarbosaurus. As such, it is worth making special note of the differences between these two and again there are some more in the palatal shelf and at the back of the maxilla. In short, it should be very hard to confuse the two if you have a maxilla of either in your hands and there is even better reason to think the two are different and thus again that Zhuchengtyrannus is a genuinely new genus.

I was also reminded in comments in yesterday’s post about ‘Tyrannosaurus zhuchengensis‘ which is detailed in the paper, but initially forgotten here! Whoops. back in the 1970’s several tyrannosaurus-like teeth were recovered from this quarry and, in the manner of the day, named as a new species: Tyrannosaurus zhuchengensis. Later on a single isolated metatarsal (foot bone) was assigned to this species. What of this? Well none of these teeth or the metatarsal show any unique features that would make them diagnostic from any other tyrannosaurin short, if you got a Tarbosaurus or Tyrannosaurus tooth or metatarsal and compared them to the T. zhuchengensis material, you wouldn’t seen any real difference. As such we cannot consider this to be valid and we therefore call Tyrannosaurus zhuchengensis a ‘nomen dubium’ –  a dubious name that should never have been created and should no longer be used (and hence the use of quote marks around it in it’s initial appearance here). Of course this material might be a much earlier record of Zhuchengtyrannus, but we can’t be sure, it might belong to the second taxon, or who knows, even another tyrannosaur!

That’s rather more than I intended to say so I’ll cut it ‘short’ there. More to come tomorrow where I’ll delve into the ecology of ZT and then we’ll be onto the glorious artwork and its genesis and importance in science communication.

Darren Tanke’s Gorgosaurus preparation 20: fixing undercuts, the final preparation

The last of the Gorgosaurus preparation (on this side) was finished February 10th. In readiness for molding, holes, cracks and undercuts have to be filled and this phase is rapidly reaching the end, too. The plan to mold the edge of the field jacket as well means the edges between the cut part of the plaster jacket and the rock itself needs special treatment.

The plaster jacket was of course made in the field with no advance knowledge that it would be molded in part later on. So these edges need to be fixed. They are rough, full of undercuts and often form vertical faces that are harder to fix to make look like rock. Most of these problematic edge areas are simply glued and crushed sand and silt thrown against the wet glue. Once dry, excess sand/silt is vacuumed off and the process repeated up to three times until the white plaster is hidden by simulated rock. Undercut areas on the edge of the jacket are fixed by using the glue/sand/silt mix which is roughly pressed into the undercut or hole, then sprinkled with dry sand/silt which is then firmly pressed (with the heel of the hand) into the damp glue/sand/silt mix underneath. This is done for any other gentle depressions or undercuts: a series of pictures are given here. Once dry the effect is quite realistic. Also, any remaining cracks are being heavily glued. I try to do heavy gluing jobs on a Friday afternoon- this way it has all weekend to dry without any disturbances from me. Come Monday morning everything has firmly set and the process begins anew until everything is done. Vertebrate paleontologist Philip J. Currie is to visit our museum (and see the Gorgosaurus) for the first time on February 18th so it is important that I be done by then.

I must apologize to readers about the image quality. The specimen, when seen in person, is really quite spectacular- the bones have a beautiful chestnut-brown to orangey-brown (more heavy on the orange) and all with a deep, rich lustre. These color qualities, which really make the specimen all that more amazing I have found very difficult to convey photographically. The overhead lighting near the Gorgosaurus has been changed this week which also has affected image quality.

All photos here and in the series are owned by Darren Tanke and the Royal Tyrrell Museum.

Late edit: Matt van Rooijen has done a colour edit on that last image to try and perk it up a bit:

Darren Tanke’s Gorgosaurus preparation 18: that superb skull

The Gorgosaurus skull (left side) was finished on January 27th. A very close visual inspection was made over the entire skull and any remaining bits of bone-colored glue, rock or sand grains removed with a scalpel carrying a #15 blade which I reshaped to suit my requirements on an oilstone and resharpened every 10 minutes or so.  A finger was then run over the the entire specimen. Any bumps, pointy bits, or rough patches were reinvestigated to comfirm they were actually bone. If not they were removed. Then a magnet was passed over the entire specimen and surrounding matrix. Magnets are not in a standard preparators toolbox but I use one at the end of each project. Several types of small wire brushes were used to carefully clean the bone surface over the past months and they do shed bristles, some quite tiny (2 mm). This specimen is to be CT-scanned by researchers in the next few months. I don’t want them coming back to me saying some foreign metal object compromised their CT-scan results. While I have kept the Gorgosaurus skull clean by brushing and careful vacuuming, I was still able to get about half a dozen metal brush bristles with the magnet.

I then washed the skull with tapwater and a standard toothbrush with firm bristles. The brush was made wet, then vigorously shaken out so it was only damp, not dripping wet. The bone surface was carefully scrubbed in a circular motion. The brush was then rinsed out in a clear container of tapwater. Each time the brush was rinsed this way, it was easy to see the water becoming more and more dirty as more of the clay particles and other minerals were removed from the bone surface. When the brush rinsed clean after each scrub it was time to stop. Then the skull was put under a desklamp with a floodlight bulb to warm up and evaporate any remaining water. The skull was then allowed to sit for an hour and cool down. This is important for the next step. A heated specimen, having more glue added to it, can have the acetone solvent “boil”, ruining the effect one is now trying to achieve.

A thin mnix of Acryloid glue and acetone was mixed and a thin layer brushed over the specimen and “scrubbed” into the bone with tight circular motions so it soaked in deeply. This glue seals any microcracks and holes. This is vitally important as the specimen is to be latex molded soon. Latex, being brushed on, gets into every nook and cranny. It can be pushed through a crack where it can expand a bit. When the cured latex is removed, the expanded bits of latex “grab” onto or anchor into the bone and require more force to pull out. This pulling action can damage the area involved and compromise the safety of the entire specimen. So it is best to seal over these potential problem areas now, rather than deal with breakage later. However, it is almost always inevitable that some breakage occurs during demolding. Once the entire skull and teeth were so treated and the glue dried within minutes, I was able to step back and get that feeling of a job well done, that every preparator experiences at the end of a project (in this case the skull only)I. I still need to finish off parts of the legs and ribs before molding happens. A molding meeting is happening the middle of next week to discuss how the molding/demolding will proceed. Hopefully in about 2-3 weeks the molding will begin- that process taking about 5 days.

[Dave adds: And now, here it is. The complete and final and finished version of the left side of the skull. Scale bar is 10 cm. And just a couple of months ago it still looked like this].

All photos here and in the series are owned by Darren Tanke and the Royal Tyrrell Museum.

Darren Tanke’s Gorgosaurus preparation 17: supporting the breaks

The last of the preparation is now being done on the Gorgosaurus. Several bones were completed on January 19th. These were the first ones to be completely finished. The nature of the rock is cracked and crumbly and despite best efforts, some rock along the edges and underneath the bones has fallen away. The bone is not properly supported and the missing rock needs to be replaced. The femur was badly affected this way. To remedy this (shown in a series of 4 pictures), I mixed some thick glue with sand from the Gorgosaurus block. Waste rock was broken up and ground into sand and dust, using a short length of a hardwood broom handle as a rolling pin. The resultant sand/dust was poured into the jar of glue and stirred together. The result was a thick paste which could be made more runny by adding more glue, or thicker by adding more sand. This paste was applied to the undercuts using a small metal spatula. Because the paste was so thick, it was easy to work and retained its shape. It dried hard in a couple hours and the bone is now safely supported. The support can be removed in the future if need be by squirting acetone onto it and removing the resulting paste. Also, once the paste is hardened, it can be shaped with an airscribe if needed. The final result is quite convincing as “real rock”.

The final treatment of the completed bones is a very thin coating of glue, made so thin that it does not sit on the bone surface, but soaks in. It seals up any remaining microcracks and dissolves and old glue on the surface. The provided picture with the brush shows part of the now fully prepared ischium, with the surface treatment of glue. Final preparation of the rest of the skull and skeleton will go quickly now.

All photos here and in the series are owned by Darren Tanke and the Royal Tyrrell Museum.

Darren Tanke’s Gorgosaurus preparation 15: finishing touches

The Gorgosaurus has entered its final phase of preparation on this side. All the bones are being worked on in a systematic fashion now. Glue that stabilized them mostly went inside the bones, but some is on the outside and rough in appearance or dirty with embedded sand/dust. All this “old glue” is carefully scrapped off and a final clean coat of thin glue applied to the surface where needed. Rough rock areas are being smoothed down. As said in an earlier update, the specimen will be molded in latex rubber. This will likely be done in one piece and how that is made will be covered in future updates if Dave Hone and the followers of this blog are interested [Edit: I most definitely am, it would be great to cover this too! Dave]. It is technically not fossil preparation but an important and often overlooked aspect of the technical side of vertebrate paleontology.

Part of the Gorgosaurus‘s final phase of preparation is getting it ready for latex molding. Molding a fossil is like chess- if you do something to the specimen, it will affect how the mold will be removed in the future? You always have to think ahead. For example a deep undercut under a bone can be molded, but once the latex cures how will it be removed from that deep undercut? Will it come off easy, or (more likely) will it be “stuck” and in the efforts to remove the mold, the bone above is damaged or possibly destroyed. With these thoughts in mind, the Gorgosaurus is being gone over section by section, looking for potential problem areas for molding and demolding as well as general areas of support. Bad undercuts are being fixed. Any low spots are obvious “weak” areas for support and latex will stick more firmly to them than a flat of slightly convex surface. These low areas are filled in. To do this, I first take leftover waste rock matrix from the Gorgosaurus and with a hammer break it up into sand grain consistency. The hole or depression to be fixed is glued and then enough loose sand it sprinkled into the low spot. A dry brush steers the sand in to small undercuts. Larger undercuts can be filled by using a small funnel made out of a piece of paper. The funnel’s tip is put under the undercut (usually meaning the funnel is angled somewhat) and pinches of sand dropped into the funnel until the problem area is filled up- this works great for microcracks only a sand grain wide too. Once this is all done, a very gentle puff of air administered by mouth gently blows away any brush marks in the loose sand. Then the loose sand is glued with acetone-based glue- the same used to stabilize the bones. Being acetone-based, it can be reversed at any time in the future if need be.

The final effect looks fairly good, but never adopts the same color as the untreated rock, but this can be rectified with paint later if wanted. The procedure is shown here in one small area and then a picture of an overall area after treatment is shown. The long and narrow belly ribs in the overall view on the right side are much better stabilized now. You may ask why not just leave the rock in there to begin with and that is usually the plan, but sometimes it is not there (due to a wide crack), or crumbled away into loose unstable pieces, or was deliberately removed for some reason (such as the removal of the postorbital from the antorbital fenestra in an earlier post) and needed to be refilled. We are hoping to start molding the Gorgosaurus block by mid February.

All photos here and in the series are owned by Darren Tanke and the Royal Tyrrell Museum.

Darren Tanke’s Gorgosaurus preparation 14: until next year…

This is the Gorgosaurus preparation update for December 15-17, and 20-23. Progress continues unabated, but is visually hard to see as so little rock gets removed now. Some days less than a sugar cubes worth is removed. Much of the work now is stabilizing rock with glue and doing fine cleaning of the bone surfaces. The last of the back of the head is now uncovered and it looks like the skull will be 520 mm long give or take a couple millimetres. The skull preparation is essentially done now- only a few minor cleaning and fixups required. Much gluing of tiny cracks is being done.

Most preparators use big eyedroppers or medical-grade syringes to inject glue, but I find both too coarse to get the job done, so I developed my own handheld modified eyedropper system years ago. My old modified eyedropper was falling apart so I recently made another. I take a plastic eyedropper and snip the tip off so it can firmly carry a medical grade syringe needle tip. The tip of the needle is carefully ground off. This is done so one does not accidently inject themselves with glue or get stabbed. We have a wide variety of needle sizes (gauges), from tiny (diameter of fine hair) to large (pencil lead diameter). The needle is pressed against a crack or hole and the bulb of the eyedropper gently but firmly squeezed. One can see the glue actually move along the crack and adjoining cracks as it wicks along. This is very time consuming, but necessary work. This is usually done on surface bone, whereas the glue bottle dispenser concept shown in a previous update is more for internal bone and matrix stabilization.

Areas of harder rock are softened with tisse paper lumps soaked in water. These are placed upon problem areas and allowed to sit for 10 minutes or so. When removed, the rock has usually softened up enough so that it can be carefully scraped off.

This will be the last update this year, they will resume early next year. Happy Holidays Everyone!

And indeed happy holidays and all that jazz from me too. See you again in a few days, I have exam papers to mark.

All photos here and in the series are owned by Darren Tanke and the Royal Tyrrell Museum.

Darren Tanke’s Gorgosaurus preparation 13: super detailed work

This is a update for Dec. 6-10 and 13-14. Much work has been done on the Gorgosaurus, in fact so much there is little left to do on this side of the block. Virtually all the bones that there are to be found have now been found. New bones since the last update are the pelvis and the base of the tail which only consists of two vertebrae and three chevrons. A meeting was held on December 14th to decide how and what to prepare in the future. It was also decided that this side of the Gorgosaurus will be moulded in latex rubber, the mould removed and then a new support jacket made before the block is turned over and preparation begin anew on the other (top) side. Right now I am mostly dealing with what is called “fine preparation” or “super detailing”. This work is the final stage of preparation. All the bone surfaces are gone over visually and with a finger to find (and feel) the last vestiges of rock or clay stuck to the bones. Small brushes and damp sponges can remove the last bits of clay. Sutures or contacts between multiple bones are highlighted by removing as much rock as is safely possible along their edges. Any repairs are mended. All holes and cracks are patched and filled. Old glue, now often contaminated with sand grains is carefully scraped off and redone as/if necessary. Rock itself is glued or reglued as needed and in places where the rock crumbled away creating seep undercuts, those areas are filled in with epoxy putty or plaster, then textured with an airscribe to look like rock. All this work will take several weeks to accomplish. As the specimen will be moulded, it is important that the bones and rock be solidified as the removal of the latex mould can cause breakage. This breakage inevitably occurs, but all efforts are made to find potential problem areas and deal with them now, rather than have to deal with broken bones later. Postings here will be slower now and likely show the specimen overall instead of featuring certain areas. The pictures here were taken on December 14 with a new higher quality camera and different lighting conditions so they appear much different than prior ones.

All photos here and in the series are owned by Darren Tanke and the Royal Tyrrell Museum

Darren Tanke’s Gorgosaurus preparation 11: a hands-free glue system

This is an update for November 29-30. Work has slowed on the Gorgosaurus lately due to the labor-intensive amount of gluing that is required. Rock is still being removed, but at a much slower pace now. This update will once again focus on glue. Glues are so important due to the often badly fragmented nature of the fossil being prepared, its host rock, or both. An American vertebrate paleontologist told me decades ago: “If the was no such thing as glue, there would be no such thing as paleontology”. A bit of stretching the truth, but he did have a valid point. Glues in vertebrate paleontology are usually applied by brush or by an eydropper, though in some cases the fossil can be simply immersed. At times a specimen requires a lot of gluing, a job that takes many hours of work, sometimes stretching into weeks of dripping drop after drop of glue onto a specimen such as a dinosaur skeleton. [Dave notes: Glues can be a nightmare too if not used properly as this link explains].

Continue reading ‘Darren Tanke’s Gorgosaurus preparation 11: a hands-free glue system’

Darren Tanke’s Gorgosaurus preparation 6: a lucky break

The X marks the problematic scute (see the text for details).

This update covers November 8-9. Much more progress has been made on the Gorgosaurus skull preparation. The eye socket area is the worst crack-wise and will likely be left until the end. Too many converging cracks make this a weak area. Late last week the thin edge of a new bone was found above the gorgosaur’s snout. This was treated at first as a disarticulated gorgosaur skull bone, but further uncovering work revealed it to be an ankylosaur (armored dinosaur) scute or piece of bony armor. This was positioned atop the skull and slightly overlapped on one side. It was an ugly piece of bone and obscured anatomical details useful for tyrannosaur researchers so I decided to remove it.

First the snout of the gorgosaur was heavily glued as was the scute and both allowed to dry. Care was taken to not glue the rock in between as we wanted to remove that. Using a sharp scalpel with a new #11 blade and an airscribe with a long stylus (tip) I was able to dig down around the scute, isolating it from the skull and pedestalling it on the rock. I then airscribed under the scute as far as I could go from nearly every direction.

Airscribing around the scute

Various preparation tools

I regularly used an old dentists mirror to inspect my progress underneath and remove any rock pieces with long-jawed forceps. In one spot the glue had soaked into the rock, thus hardening it. Because the glue is solvent-based I simply squirted as small amount of acetone on it and soon the glue gave way and I could remove the gooey glue and sandstone mass as required. When I was about to pull the scute away, it broke on the end that covered the side of the gorgosaurs snout. This might be a tragedy to some (It broke! GASP!) , but it was truly what preparators and field workers call a “lucky break”. Not only did it give me more access with the scalpel and airscribe, but importantly, it exposed a previously hidden badly cracked and weak area of the snout. This could have shattered had I pulled the scute off prior. These new cracks in the snout were now fully exposed and thus could be repaired easily. The scute was then wiggled back and forth and some water squirted underneath until it came loose without any more problems.

The cracks in the bone under the scute

On November 9th it was confirmed that some of the gorgosaur skull has in fact become disarticulated. In the antorbital region in front of the eye socket I removed what looks like an epipterygoid (part of the braincase). Research papers are very useful at this stage to identify bones and plan for their extraction. Next to it was a large bone end which has been confusing, but was eventually identified as the right postorbital (bone forming upper half of eye socket). Curiously, 75 million years ago this fell off the back of the skull, moved forward to the middle of the skull and was flipped around so the top of the bone is now the bottom (and bottom is top) and flipped again so front is back and back is front. After all that it was then pushed somehow across the middle of the skull so this right skull bone is on the left side of the head! Water currents? Scavengers?

The skull as of the 9th of November

I will be removing the errant postorbital in the next day or so. I am also now finding some of the very thin palate bones. I can only expose a few millimetres at a time, glue the exposed bone, wait an hour or two and then repeat. It is very tricky work as the bone is as thin a rice paper. One wrong move and it is ruined forever.

More to come soon. All photos here and in the series are owned by Darren Tanke and the Royal Tyrrell Museum.

Darren Tanke’s Gorgosaurus preparation 5: fixing the cracks

The report covers November 3-4. More of the Gorgosaurus skull was uncovered, but the work slows down a bit on account of shattered rock, cracks in rock, and complex anatomy. Some of the gorgosaur bones were hollow in life or quite thin (playing card thickness) so work has to go more slowly. Additionally some of the teeth are being detailed and the chin region restored.

Cracked fossil bone needs repair. Traditionally cracks were simply filled with plaster but this is only a filler, it has little to no bonding strength and can get onto the adjacent good bone surface obscuring critical details to researchers. Another way to fix cracks is to inject glue until the crack fills up, but I have seen instances where the crack was bottomless and the glue was dripping out of the bottom of the field jacket. No good! This means the specimen is now effectively glued to the jacket which is something very hard to impossible to reverse. More control was clearly needed.

Over a decade ago I developed a technique whereby tissue paper (brown in color and unbleached or colored) is put into the cracks. Small pieces are pulled off the sheet of tissue and loosely rolled between thumb and forefinger. This “sausage” of paper is then laid atop the crack and pushed in with a sharp scalpel blade which chops up the fibres and pushes the tissue paper down. This process is repeated (if necessary) until the crack is filled to near the top. Then strong and runny glue is carefully squirted onto the paper. The paper soaks up the glue so it does not drip through to the jacket. Several coats of glue will make the glued paper progressively darker, but once dry it is still easily differentiated from the real bone by color and texture. The use of unbleached and uncoloured paper is made because of no added chemicals that might react over time. Specimens so prepared 15 years ago are still in excellent shape. I show a sequence of events to repair a crack in the left postorbital bone. The final work on this and other cracks will be done when the last preparation of the skull and skeleton is done. This paper technique is also good for filling cracks in matrix- the same procedure is done but then ground up matrix is sprinkled on top of the wet glue. When dry and the loose matrix dust are brushed away, the crack not only disappears, but is now firmly stabilized.

The Gorgosaurus skull picture shows it after 5 days of preparation work on November 4th. I can only put a half day on the Gorgosaurus on Nov. 5th so the next progress report will not be submitted until early next week.

More to come soon! All photos here and in the series are owned by Darren Tanke and the Royal Tyrrell Museum.

Darren Tanke and Gorgosaurus

So as you should now know, coming up is a series of posts from Darren Tanke as he prepares his way through a new Gorgosaurus specimen. This is really cool as this is, naturally, the first time this specimen will be unveiled as it were – you’ll get to see something new as it happens. It seemed appropriate at the start to give a bit of an introduction to Darren, and indeed to the dinosaur he’ll be working on.

Darren works at the legendary Royal Tyrell Museum in Drumheller, Canada which is heaving with local Late Cretaceous dinosaurs and other taxa. He’s been there over thirty years now making him the longest serving employee there (perhaps unsurprisingly). His formal job, as it were, is that of a preparator – preparing the rock from the bones of fossils and repairing and restoring them for study and display. However, Darren’s work goes well beyond this and he is known and respected as a researcher in his own right with dozens of papers to his credit (see his page or check out his Wikipedia entry, and yes, he has one of them too!).

Darren has carried out fieldwork all over the world and is particularly well know for finding lost quarries. Sadly many researchers in the early days were not always great at marking out where their specimens came from and Darren has made it a special task of his. He’s also done a lot of work on the history of palaeontology with papers on the history of important specimens or researchers.

For those who don’t realise, this is seriously impressive. While many preparators do contribute to research papers thanks to their work and knowledge there are not so many out there that have published more than a handful of papers, and especially not as a regular lead author. I’m delighted to have him contribute on here with both hats on as a researcher and preparator.

Moving onto Gorgosaurus, while not famous itself, and therefore perhaps unfamiliar, its cousin Tyrannosaurs certainly should be.  Yes Gorgosaurus is one of the giant tyrannosaurs and while a little smaller than rexy is hardly unimpressive – around 8 m or so long and at least a couple of tons in mass at adult, this is not a small carnivore. It is a classic tyrannosaur with a large head, robust teeth, small arms and the rest. If you don’t already have a good idea of what to expect then take a look at this post showing a juvenile prepared by you know who. It dates from the Campanian in the Late Cretaceous (so that’s about 75 million years ago) and lived alongside another large tyrannosaur – Daspletosaurus.

As for the upcoming project believe it or not I have no idea what Darren has lined up for us. All he has told me is that it is a nice specimen and shouldn’t take too long to prepare. I simply haven’t asked and have yet to see a photo of it or anything, so I’m genuinely excited to see what is coming. Above is a photo of the excavation, but obviously it doesn’t reveal that much (photo from the Tyrell’s Facebook page here) though Darren has revealed that it had to be taken out by helicopter so it’s clearly not going to be a small one.

Just as a final bit of housekeeping, while Darren will be writing these posts, I’ll be filing them under the ‘practical palaeontology’ banner rather than ‘guest posts’ as it should make them easier to find for more people. Tune in shortly when we’ll kick off and Darren will reveal the specimen for the first time and tell us what his plans are for it.

Special Guest Post series coming soon

The guest posts on the Musings are generally very popular, indeed I’m often a bit peeved that more people seem to want to read other people’s work on here than mine. No matter, it’s great to have different voices on here and ones that fill in the gaps that I’m unwilling or unable to blog about.

I do bug people from time to time when I know something interesting is coming up and most people are very generous with their time. One of these is preparator and researcher Darren Tanke who is likely familiar to many on here. Some time ago I asked Darren if he might be interested in writing about a Gorgosaurus specimen he was preparing. Sadly he was too busy, though he was most generous with images of the fantastic specimen. However, Darren did have another idea and that is finally coming to pass.

Thanks to the generosity of the Royal Tyrell Museum where he works, Darren is going to be giving us a blow by blow account (with photos) of preparation on another Gorgosaurus. Stick with us for the next few weeks and Darren will be showing the progress made on this tyrannosaur and talking about the techniques used. I am, naturally, extremely excited about this project and very grateful to both Darren and the Tyrell. I’ve never covered the skills and techniques of preparing fossils in the depth I’d like and that is about to be corrected in a very special way.

Stay tuned!

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