Poll: Who wins?
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Dakotaraptor steini
66.67%
2 66.67%
Dilophosaurus wetherilli
33.33%
1 33.33%
Total 3 vote(s) 100%
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Dakotaraptor steini v Dilophosaurus wetherilli
#16
Back on topic...

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Whipped up a comparison between the two. It should be noted that Dilophosaurus was an exceptionally gracile animal, and I doubt the weight difference between the two varies much between extremely small and negligible. That being said, Dakotaraptor offers a particular challenge when placed in comparison with other animals- whoever posed it for various skeletals needs to be taken around back and shot. I mean honestly, what the hell is this?.

Because of this odd running pose, it looks Dakotaraptor has an extreme height advantage in the comparison. This is not the case. In life the animal probably was only slightly taller due to its more cursorial legs.

It should also be noted that this is the Dakotaraptor model that is currently accepted. In reality, if you look at link I just made fun of, we really don't have much of the animal. Just an arm, some leg, and vertebrae. We honestly have no idea what its skull looks like.

Having said all of this, I'd favor the Dakotaraptor in its current state over the Dilophosaurus due to its more robust predatory features. However, because said robust predatory features are little more than conjecture at the moment, I will reevaluate as more information is unearthed about the Plunderer of Dakota.
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#17
It's there any weight estimates for dakotahraptor, that's is a primary issue when it comes to match ups involving this drom.
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#18
Estimates that I’ve read put it between 250-450kg, but these estimates are usually based upon the more robust Utahraptor, anecdotal, or both.

That being said, I do think those estimates capture the animal’s actual weight with how wide of a net that’s casted.
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#19
So probably somewhere in 350kg on average? 

Dilophosaurus not only seems to lack a size and robusty advantage, but also holds no major advantage when it comes to weaponry? along with the drom having secondary weaponry in comparison?

Could this be considered a mismatch or not?
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#20
(09-04-2018, 10:50 AM)Aztec Wrote: So probably somewhere in 350kg on average? 

Dilophosaurus not only seems to lack a size and robusty advantage, but also holds no major advantage when it comes to weaponry? along with the drom having secondary weaponry in comparison?

Could this be considered a mismatch or not?

Well, I dont think it would be considered a mismatch per say, but I do favor the raptor.

What I am most interested in is developments that occur regarding the Dakotaraptor's skull. Its reconstruction seems to be based upon Utahraptor, which had a skull with a very robust morphology and was the exception rather than the norm compared to most raptors.
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#21
Spinodontosaurus on the previous forum said something about Dilophosaurus as an adult (based off of the seemingly only known adult, in fact) probably weighing at least >500 kilograms (or over 600 kilograms). Also, according to him, most reconstructions of Dilophosaurus are based off of subadult material, not the adult specimen. So we could probably expect it to be more robust to some (unknown) degree as well.

Its weaponry was fine too. The skull doesn't look strong, but "The fibrous connections between skull elements would have provided shock-absorbing elasticity, ample tensile strength, and elasticity" (The Dinosauria: Second Edition (p. 69)). The maxillary teeth were serrated (as expected for a theropod) and exceptionally long. And, of course, claws (on both manus and pedes) to use too, even if not in the same league as the dromaeosaurid's.

Going by this, I favor Dilophosaurus for now.
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#22
(09-04-2018, 01:07 PM)Ausar Wrote: Spinodontosaurus on the previous forum said something about Dilophosaurus as an adult (based off of the seemingly only known adult, in fact) probably weighing at least >500 kilograms (or over 600 kilograms). Also, according to him, most reconstructions of Dilophosaurus are based off of subadult material, not the adult specimen. So we could probably expect it to be more robust to some (unknown) degree as well.

Its weaponry was fine too. The skull doesn't look strong, but "The fibrous connections between skull elements would have provided shock-absorbing elasticity, ample tensile strength, and elasticity" (The Dinosauria: Second Edition (p. 69)). The maxillary teeth were serrated (as expected for a theropod) and exceptionally long. And, of course, claws (on both manus and pedes) to use too, even if not in the same league as the dromaeosaurid's.

Going by this, I favor Dilophosaurus for now.

I dont disbelieve you here, but the nomen nudum D. Breedorum is the largest specimen of D. Wetherilli yet discovered. A quick search yields a result of an estimate of 400kg, with the smaller green D. Wetherilli weighing an oddly specific 283kg. In either case, not exactly an animal with a huge size advantage.

Take these numbers with a grain of salt, of course. I cant find the methods used to attain said numbers or other sources that credit them (unless my ape brain is not processing something correctly). Could you link me to Spinodontosaurus' post if it's archived? I'd love to read it over.

My only real issue is that I fail to see how having elasticity and tensile strength makes the skull strong. That makes the skull flexible, but doesn't yield a powerful bite or even a particularly structurally sound skull. The Dakotaraptor makes up for its lack of impressively long teeth (as far as we know) with equally large or larger claws on its hands and feet. I dont see how the Dilophosaurus really outclasses it in that sense. I only see it besting the raptor more often than not with a notable size advantage.
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#23
Quote:I dont disbelieve you here, but the nomen nudum D. Breedorum is the largest specimen of D. Wetherilli yet discovered.
That's exactly what Spinodontosaurus said (and what I implied). He called it the "largest and seemingly only known adult specimen" and then again called the D. "breedorum" specimen an adult.

Quote:A quick search yields a result of an estimate of 400kg, with the smaller green D. Wetherilli weighing an oddly specific 283kg. In either case, not exactly an animal with a huge size advantage.
I don't remember what that was based off of, but here was Spinodont's rationale for his weight estimate for whatever it's worth.

Quote:The largest and seemingly only known adult specimen is >6.5 meters long and has a femur 59 cm long, comparable to the likes of Utahraptor (60 cm), Ceratosaurus nasicornis (62 cm) and Ceratosaurus magnicornis (63 cm; probably a synonym of C. nasicornis). They are usually estimated to weigh in excess of 500 kg too and in all 3 cases I reckon are probably closer to or over 600 kg. For example I estimated the adult C. dentisuclatus specimen at ~950 kg via GDI and this specimen is only ~15% larger than the two Ceratosaurus specimens mentioned above, implying they could have weighed >600 kg. So I think a weight of >500 kg is possible for Dilophosaurus, at least for the adult.

Also, depending on the weight estimate for Dakotaraptor, Dilophosaurus could still have a substantial size advantage even if it was just 400 kilograms (e.g. 250 kg drom versus 400 kg dilophosaur).

Quote:Take these numbers with a grain of salt, of course. I cant find the methods used to attain said numbers or other sources that credit them (unless my ape brain is not processing something correctly). Could you link me to Spinodontosaurus' post if it's archived? I'd love to read it over.
It was on the previous forum, so you'd have to log into the Carnivora archives to see it. I've screenshotted it for you here.

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Quote:My only real issue is that I fail to see how having elasticity and tensile strength makes the skull strong. That makes the skull flexible, but doesn't yield a powerful bite or even a particularly structurally sound skull. The Dakotaraptor makes up for its lack of impressively long teeth (as far as we know) with equally large or larger claws on its hands and feet. I dont see how the Dilophosaurus really outclasses it in that sense. I only see it besting the raptor more often than not with a notable size advantage.
What? The fibrous connections at the cranial joints would have held them together very tightly. We're not talking about some weak articulation of soft tissue, we're talking about ligaments with very high tensile strength maintaining structural integrity. Hence providing great tensile strength at those joints (making it difficult to dislocate those joints and damage the skull with force) and a bit of "give" to the skull whenever forceful loads were placed on it (the strong ligaments allowing a bit of bending/deformation at their sites and then returning back to normal once the load was gone).

I don't expect the Dilophosaurus to bite particularly hard (and that's dependent on other things about its cranial and dental morphology too) or to suddenly have the heavy duty skull strength of say, a tyrannosaurid, but enough to deal with another large animal.

I also only said that Dilophosaurus' weaponry was fine, nothing about it outclassing the dromaeosaur's. I actually think Dilophosaurus wins if only for what I think is a probable size advantage.
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#24
(09-04-2018, 10:15 PM)Ausar Wrote:
Quote:*snip*


I really appreciate you posting that! The more you know!

What I'd like to point out is that Spinodontosaurus states:

Quote:For example I estimated the adult C. dentisuclatus specimen at ~950 kg via GDI and this specimen is only ~15% larger than the two Ceratosaurus specimens mentioned above, implying they could have weighed >600 kg. So I think a weight of >500 kg is possible for Dilophosaurus, at least for the adult.

He doesnt state anything about a Dilophosaurus reaching or surpassing 600kg, that number is in reference to C. nasicornis.

So, let's assume that we're considering the Dilophosaurus does surpass 500kg, we're still considering a maximum estimate based on one specimen of fragmentary remains. I feel its also fair to give Dakotaraptor the same treatment, with the highest estimate I've seen yet being 450kg. In such a case, I'd still favor the Dromeosaur.

Of course, again, that 450kg estimate is fairly liberal, and can be disputed fairly easily.

Spinodontosaurus' post bases a lot on the animals having fairly similar proportions, too. I'd be interested to see how wide-bodied C. nasicornis  are compared to Dilophosaurus.
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#25
Quote:He doesnt state anything about a Dilophosaurus reaching or surpassing 600kg, that number is in reference to C. nasicornis.
He didn’t flat out state it, but he pointed to theropods with similarly long femora with body masses probably over 600 kg.

Quote:The largest and seemingly only known adult specimen is >6.5 meters long and has a femur 59 cm long, comparable to the likes of Utahraptor (60 cm), Ceratosaurus nasicornis (62 cm) and Ceratosaurus magnicornis (63 cm; probably a synonym of C. nasicornis). They are usually estimated to weigh in excess of 500 kg too and in all 3 cases I reckon are probably closer to or over 600 kg. For example I estimated the adult C. dentisuclatus specimen at ~950 kg via GDI and this specimen is only ~15% larger than the two Ceratosaurus specimens mentioned above, implying they could have weighed >600 kg. So I think a weight of >500 kg is possible for Dilophosaurus, at least for the adult.

Either way, >500 kg is still quite a hefty advantage over most Dakotaraptor body mass estimates I’ve seen (actually, I don’t remember estimates up to 450 kg to be honest).

[quote]So, let's assume that we're considering the Dilophosaurus does surpass 500kg, we're still considering a maximum estimate based on one specimen of fragmentary remains. I feel its also fair to give Dakotaraptor the same treatment, with the highest estimate I've seen yet being 450kg. In such a case, I'd still favor the Dromeosaur.[/auote]
The one maximum sized Dilophosaurus we have is supposedly the only adult specimen known. So too are the Dakotaraptor specimens we have (to my knowledge). We can pit a potential 450 kg raptor against the dilophosaur if we want, but it would still be “fair” to use lower estimates for the former too (the reason I did so initially was because I don’t remember reading estimates up to 450 kg).
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#26
I think we all know that estimating body masses based on femur having a similar length to other more distantly related and robust theropods isn't exactly the most precise method of measurement. (aside from the case of Utahraptor, although it was fairly robust by raptor standards as well). For all we know, the current estimate COULD be based on the adult specimen, we're just not sure. To achieve the sizes listed we're assuming that didn't happen. If we're considering minimum estimates we have a 280kg Dilophosaurus against a 220ish raptor.

On the topic of Dakotaraptor, you probably don't remember them because, admittedly I don't think there are any. At least none that are official. There isn't enough of the Dromeosaur to really estimate it's weight with any real confidence. As I said earlier, everything that is out there is anecdotal at best.

So I think a weight of >500 kg is possible for Dilophosaurus, at least for the adult. Saurian's wiki has this listed, and it's the highest estimate I've yet seen.

Quote:A common misconception is that Dakotaraptor has beaten Utahraptor as the largest dromaeosaurid, but this is untrue. Utahraptor was 7 metres (23 ft) and 500 kg (1,100 lbs), while Dakotaraptor was 5.5 metres (19.6 ft) and 453 kg (1,000 lbs) but were on a similar scale.

Of course, because it's anecdotal, take it with a grain of salt as there aren't any sources and no methods for how this number was achieved. It's far from incontestable.
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#27
Quote:I think we all know that estimating body masses based on femur having a similar length to other more distantly related and robust theropods isn't exactly the most precise method of measurement.
Of course we do, but I do think femur length is at least a reasonable proxy for body mass if we were comparing certain animals (particularly some select theropod taxa). I didn't/don't think there was anything remarkable about Dilophosaurus' femur length relative to body mass (not like say, Tyrannosaurus, which has a shorter, more robust femur than some other theropods its mass). Of course, I won't mind being proven wrong.

Quote:For all we know, the current estimate COULD be based on the adult specimen, we're just not sure. To achieve the sizes listed we're assuming that didn't happen.
Just because I feel like I should buttress (or dismiss) the idea that the "breedorum" specimen is the only adult specimen of the species we have, I'll try to ask to another knowledgable person on the matter when I get the time (another poster on the previous Carnivora, but he hardly ever posts on this forum anymore; Spinodontosaurus hasn't posted on Carnivora for a while, unfortunately, so he's not going to be defending his thought process here anytime soon).
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#28
(09-06-2018, 11:54 AM)Ausar Wrote: Of course we do, but I do think femur length is at least a reasonable proxy for body mass if we were comparing certain animals (particularly some select theropod taxa). I didn't/don't think there was anything remarkable about Dilophosaurus' femur length relative to body mass (not like say, Tyrannosaurus, which has a shorter, more robust femur than some other theropods its mass). Of course, I won't mind being proven wrong.

Quote:For all we know, the current estimate COULD be based on the adult specimen, we're just not sure. To achieve the sizes listed we're assuming that didn't happen.
Just because I feel like I should buttress (or dismiss) the idea that the "breedorum" specimen is the only adult specimen of the species we have, I'll try to ask to another knowledgable person on the matter when I get the time (another poster on the previous Carnivora, but he hardly ever posts on this forum anymore; Spinodontosaurus hasn't posted on Carnivora for a while, unfortunately, so he's not going to be defending his thought process here anytime soon).

Well, in that case Dakotaraptor might be a much larger than anticipated. It's femur was 55.8 cm long, quite comparable to the Dilophosaurus' 59 cm femur.

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Source.

If you get the chance, please DM me or post here. I'd love to find out more on the topic!
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#29
I got a response from the former Carnivora poster after he returned from SVPCA (well, I have had it since the 8th, but I never checked to see if he responded since before then). Here's what he said.

Quote:Ok, so have you already read what the theropod database has to say on the matter? I haven’t yet checked out most of the publications.

Reading Welles 1984 (holotype description), yes, the holotype does seem to have unfused neurocentral sutures in its dorsals, although the these seem to be fused, if not completely closed, in the cervicals (interesting enough–I don’t know much about suture fusion patterns in theropods though–that’s the opposite direction in which I’d expect fusion to take place from studying sauropodomorphs), so it is probably appropriate to call it a juvenile or subadult based on the criterium of osteological immaturity (if the sutures are unfused, we can usually assume it was still in a fast growth phase, which is the best proxy for immaturity and the most interesting criterium in terms of how it relates to adult size.
Now, we need to get our terminology straight here; most dinosaur specimens obviously weren’t fully grown yet, but for the sake of simplicity let’s distinguish between adults, presumed sexually mature, which may still be growing noticeably but have already noticeably decellerated growth rates, and subadults, which are in a phase of fast growth.
So this 6m individual probably would have had quite a bit left to grow, that much I think is reasonable (how much is impossible to accurately predict though). More than your typical theropod with fused neurocentral sutures that is classified as an adult at least.

However these terms are not used consistently in the literature and it’s important to keep in mind that one paper’s subadult may be another paper’s adult. And that’s not even including different (histological, morphological, sexual, ecological etc.) criteria, which are all valid points depending on the different inferences we want to draw. In short, dinosaur growth is a freakin’ mess and actually not very well understood yet.


Quote:This got me interested, because it seems like commonly cited mass estimates for Dilophosaurus (less than 300kg for the holotype) are very low. So I took Hartman’s skeletal and adapted the dorsal view from Paul’s Megapnosaurus/Syntarsus/Coelophysis/whateveritis rhodesiensis to fit the segment lengths of Dilophosaurus. I didn’t change the ribcage width, although I think Paul may be underestimating it, but I did add a slightly beefier neck and tail base. So all in all, I think I’ve been fairly conservative. What I ended up with is a volume of 438l when scaled to a 6m axial length. At an assumed density of 0.9, that’s 394kg, i.e. just shy of 400kg for the holotype.
Quote:References: 

Hartman, Scott. 2015: New-look Dilophosaurus. DeviantArt. Downloaded from www.deviantart.com/scotthartman/art/New-look-Dilophosaurus-553959249 on 9 September 2018.

Paul, G. S. 2016: The Princeton field guide to dinosaurs. Princeton University Press, Princeton.



Quote:So from that and the vertebral measurements, we can probably figure out pretty well how big the D. "breedorum" specimen would be, though just using the femur and skull gives me pretty disparate results (468 and 660kg respectively).


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Quote:Btw yes, I WAS too lazy to model the crest or digits, but I assumed the impact on the mass estimate would be pretty insignificant.


Quote:Using the theropod database figures for all overlapping presacrals, UCMP 77270 is on average 12.7% bigger. However, that is because the 6 overlapping cervicals are on average just 2.7% longer. In only the 5 dorsals, there is a 20.9% difference between the two.
Quote:So D. "breedorum" probably had a proportionately shorter neck, which is in accordance with its larger skull. So I’d advocate scaling mass from the dorsals, but length from the average of everything.



In other words, "breedorum" would probably be ~6.8m long, at least if the tail/presacral proportions stay the same (which I didn’t bother to check). But it’s probably closer to 77% more massive judging from the length of just the dorsals, i.e. 696kg. I’m assuming the neck and most of the tail aren’t very heavy, so making them proportionately shorter wouldn’t have an impact of more than a few, or at best a few tens of kilos. If we want to be very conservative though, the absolute lower bound would be 565kg, based on all presacrals, but that is certainly too low, especially considering the dorsal column is less complete than the cervical one which artificially inflates the importance of the cervicals for the length estimate.



This is interesting, as it hints at pretty significant allometry in this taxon’s growth (negative allometry of neck and femur, positive allometry of skull and torso with respect to overall size). Coming full circle, this also supports the assessment that the holotype is immature.
So in conclusion, it’s probably save to say that adult Dilophosaurus could at least approach 7m and mass in excess of 600kg, and that is more representative of the species as a whole than the holotype or other subadult specimens.

Quote:I’ll probably write that up into a post as soon as I can decide on what thread it would be appropriate for, but if you want to quote or post any of it in your discussion on carnivora, feel free to do so (I’m not going to bother making a new account over there for now).


Quote:Note though that I haven’t looked into the mass of Dakotaraptor like, at all, so I’m not necessarily saying its weight isn’t also being underestimated. But 280kg for the Dilophosaurus holotype are definitely too low. Probably one of the old femur-circumference or femur length-based estimates. And D. breedorum is definitely a lot bigger than this individual. So the lower figures that this maxilla-guy juggles around with are probably off, and Spinodontosaurus figures’ are probably pretty good.


Quote:On the ontogenetic stages, I’ve done my readind (well, let’s call it skimming) now. I think Mortimer took the ontogenetic status straight from Welles (1970) and Tykoski (2005). 

In his 1970 short communication naming the genus, Welles refers to the type and UCMP 37303 and describes the latter as a "similar sized juvenile". It is not totally clear if he means to imply that both are juvenile, or just the latter, but as I already mentioned I think from his description it is clear that it is, and subsequent work agrees. UCMP 77270 (D. "breedorum") is also mentioned as part of the type series (which actually makes is another paratype if it is referrable to D. whetherilli) and considered an adult, estimated as approximately one third larger than the holotype.

Gay (2001) describes some further material, including at least one juvenile. It stands to reason that the pubis he describes measuring 57cm (18% larger than the restored pubis length of the holotype) is likely to be from an adult, or at least it’s probably similar in size to UCMP 77270. MNA P1.160 and 161 are the proximal and distal ends of a partial femur, which estimated at 56cm when complete, similar to the holotype but we don’t know its ontogenetic status. It’s certainly possible that it was from a smaller adult, but also possible, and more likely, that it’s a subadult.

Tykoski (2005) states the following: "Nearly all the known specimens of Dilophosaurus wetherilli and Liliensternus liliensterni were sub-adult or juvenile individuals, a fact pointed out by Rowe and Gauthier (1990)." He also mentions TMM 43646, with a femur ~75% the size of UCMP 77270’s, as being probably even less mature than the type and subadult paratype specimens.

So everything points to UCMP 77270 being a pretty normal-sized adult. Nothing points to it being an unusually large specimen, except when compared to the subadults.

Gay, R. 2001: New specimens of Dilophosaurus wetherilli (Dinosauria: Theropoda) from the early Jurassic Kayenta Formation of northern Arizona. Mesa Southwest Museum Bulletin 8:19–23.
Tykoski, R. S. 2005: Anatomy, ontogeny, and phylogeny of coelophysoid theropods.PhD Thesis, University of Texas at Austin.
Welles, S. P. 1970: Dilophosaurus (Reptilia, Saurischia), a new name for a dinosaur. Journal of Paleontology 44:989.
Welles, S. P. 1984: Dilophosaurus wetherilli (Dinosauria, Theropoda). Osteology and comparisons. Palaeontographica Abteilung A:85–180.

Quote:Regarding Dakotaraptor, here’s Franoys’ mass estimate for the holotype of Utahraptor: comments.deviantart.com/1/643064419/4642125804

Based on the remains, I’d highly doubt Dakotaraptor would be much heavier than this, though it would be considerably taller due to its more elongated limb proportions.

Quote:Actually, I revise my previous estimate slightly downwards, putting a little more work into the model now I think the previous one had an overly squarish cross-section. That is not to say that the cross-section being perfectly elliptical is necessarily the most accurate, but it’s what’s commonly assumed so for consistency’s sake I should adopt it too.
Quote:Based on a new model that’s elliptical in cross-section, I’m getting 0.366m³ for the 6m Holotype. Using a density of 0.9 that would end up at 330kg (although I think a case could be made for a slightly higher density in this case, as this is a very basal theropod and not that strongly pneumatised). That would put the adult scaled based on the dorsal vertebrae at 581kg.
Of course the rest of the assumptions remain quite conservative, as the dorsal view is from an animal only half the length and might be too slender because of Greg Paul’s methods to begin with. But yeah, approaching 600kg for adult Dilophosaurus is probably more realistic than 700. Still not a small animal though.

Quote:[Image: FP7RFgseS8CKm2S9OWN1m6fG8O93e6avFtB6U_Lv...57-h765-no]


Quote:www.deviantart.com/theropod1/journal/Dilophosaurus-size-763587791

Actually it seems there might be some mixum in the theropod database with the holotype's vertebrae. The adults dorsals are on average just 12% longer, not 20. Welles labels the anterior 5 dorsals confusingly as pectorals and starts counting the dorsals from what I would call d6, from the measurements in Welles 1984 it looks like Mortimer included some of those pectorals as dorsals but not all.
It would really be noce to have the description of the specimen, but not much hope of that...

Quote:Sorry for the many revisions. Not all that easy to estimate after all, especially as I (and most of the rest of the scientific community) have no access to the inofficial "description" of D. breedorum. But I doubt it will get any lighter than this, unless we assume lower densities.
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