Another look at the smallest adult pterosaur – AND its hatchling

Earlier we looked at the smallest adult pterosaur, B St 1967 I 276 or No. 6 in the Wellnhofer (1970) catalog. Here (Fig. 1) it is compared to an adult leaf chameleon, Brookesia micro, one of the smallest living lizards and to the Bee hummingbird, one of the smallest living birds. Also shown are their hatchlings and eggs.

Figure 1. The smallest of all adult pterosaurs, B St 1967 I 276 or No. 6 in the Wellnhofer (1970) catalog compared to scale with the living leaf chameleon (Brookesia micro) sitting on someone's thumb. Also shown are hypothetical eggs and hatchlings for both. These lepidosaurs had tiny eggs and hatchlings.

Figure 1. The smallest of all adult pterosaurs, B St 1967 I 276 or No. 6 in the Wellnhofer (1970) catalog compared to scale with the living leaf chameleon (Brookesia micro) sitting on someone’s thumb. Also shown are hypothetical eggs and hatchlings for both. These lepidosaurs had tiny eggs and hatchlings, relatively larger in the chameleon, based on pelvis size and average 1/8 size for other pterosaur hatchlings.

 

Traditional paleontologists
don’t buy the argument that No. 6 was an adult, even though it is much larger than the smallest lizard and about the size of the smallest bird. Worse yet, they refused to test it in phylogenetic analysis. So, the  impasse remains.

Figure 2. Smallest known bird, Bee hummingbird, compared to smallest known adult pterosaur, No. 6 (Wellnhofer 1970). Traditional workers consider this a hatchling or juvenile, but in phylogenetic analysis it does not nest with any 8x larger adults.

Figure 2. Smallest known bird, Bee hummingbird, compared to smallest known adult pterosaur, No. 6 (Wellnhofer 1970). Traditional workers consider this a hatchling or juvenile, but in phylogenetic analysis it does not nest with any 8x larger adults. This image is slightly larger than life size at 72dpi. Note the much smaller eggs produced by the tiny pterosaur. 

 

Pictures tell the tale.
You can see for yourself. No. 6 is substantially smaller than other tiny pterosaurs just as the bee hummingbird is substantially smaller than other hummingbirds.The hatchling was substantially smaller than both the leaf chameleon and bee hummingbird hatchlings based on their larger egg size/pelvis opening.

Earlier we looked at isometric growth in several pterosaurs, with hatchlings matching adults in morphology. Earlier we also took note of the danger of desiccation to hatchling pterosaurs until they reached a certain size/volume, so they probably roamed the leaf litter, which is probably when pterosaurs became quadrupeds and developed elongate metacarpals 4x.

References
Hedges SB and Thomas R 2001. At the Lower Size Limit in Amniote Vertebrates: A New Diminutive Lizard from the West Indies. Caribbean Journal of Science 37:168–173.
Wellnhofer P 1970. 
Die Pterodactyloidea (Pterosauria) der Oberjura-Plattenkalke Süddeutschlands. Abhandlungen der Bayerischen Akademie der Wissenschaften, N.F., Munich 141: 1-133.

wiki/Pterodactylus

The breakup of the Tyrannosauroidea is not going over well.

Earlier the large reptile tree (Fig. 4) nested Tianyuraptor, Zhenyuanlong, Ornitholestes and Microraptor in the same clade as Tyrannosaurus. At the same time the LRT nested former long rostrum tyrannosauroids, like Dilong, Guanlong, Proceratosaurus, and Xiongguanlong with spinosaurs. That differs from prior published studies.

In correspondence with the author
of a recent tyrannosauroid paper, the author made these statements with regard to the cladogram (Fig. 4) that I sent along, “Your tree is so iconoclastic* that, if correct (or even remotely correct), it means that everyone else working in theropod systematics over the past two decades has been blatantly wrong. Having spent many years working on tyrannosauroids and dromaeosauroids I can’t fathom why you’re not finding a monophyletic Tyrannosauroidea, or why you’re placing some tyrannosauroids with abelisaurids (Yutyrannus + Majungasaurus), or how Tyrannosaurus could possibly be linked with Zhenyuanlong/Tianyuraptor. The last one in particular is, let me put it frankly, impossible.”
iconoclastic = characterized by attack on cherished beliefs or institutions.

Well, I’m not trying to promote the impossible.
This is just what you get when you plug the numbers in to the LRT, where all sister taxa look similar to one another (see below). I know why the LRT recovers the sisters that it does (see below). I don’t know why prior studies recover the sisters that they do.

At the heart of science
is an essential balance between two seemingly contradictory attitudes –
an openness to new ideas, no matter how bizarre or counterintuitive,
and the most ruthlessly skeptical scrutiny of all ideas, old and new.
This is how deep truths are winnowed from deep nonsense.
— Carl Sagan —

I have attempted to be ruthless,
trying to see what it would take to shift taxa back to their traditional order. I have to say, I have failed to do so in the Theropoda. This topology appears to make more sense here and the scores reflect that.

Something I should have done earlier
is provide side-by-side comparisons (Figs. 1-4). Of course, the LRT dataset is available to anyone on request.

Tyrannosauroids are most readily united by
their relatively deeper rostra, short necks and short torsos. This also gives them the impression of having longer hind limbs. The pubis is not oriented posteriorly, as in dromaeosaurids like Velociraptor (Fig. 1).

Figure 1. Tianyuraptor and Zhenyuanlong compared to Tyrannosaurus and to Velociraptor. The two taxa in question traditionally nest with the latter.

Figure 2. Tianyuraptor and Zhenyuanlong compared to Tyrannosaurus and to Velociraptor. The two taxa in question traditionally nest with the latter. Tyrannosauroids are united

The sisterhood of 
Ornitholestes, Tianyuraptor and Microraptor are readily visible here (Fig. 2). I hope the sisterhood of Tyrannosaurus, Zhenyuanlong and Tianyuraptor is also obvious (Fig. 1) as opposed to the dromaeosaurs shown above.

Figure 1. Tianyuraptor and Zhenyuanlong compared to Tyrannosaurus and to Velociraptor. The two taxa in question traditionally nest with the latter.

Figure 1. Tianyuraptor and Zhenyuanlong compared to Tyrannosaurus and to Velociraptor. The two taxa in question traditionally nest with the latter.

The long-rostrum taxa here removed from
the tyrannosauroids all nest more parsimoniously with spinosaurs and their kin, including Deinocheirus (Fig. 3). Compare them all to Albertosaurus and decide for yourself which one is the oddball here.

Figure 3. The former tyrannosauroid, Xiongguanlong, now nesting with spinosaur sisters Deinocheirus and Sinocalliopteryx rather than like Albertosaurus, a genuine tyrannosaur. The long snout of Xiongguanlong does not mean it is an aberrant tyrannosaur. Rather it is a standard pre-spinosaur.

Figure 3. The former tyrannosauroid, Xiongguanlong, now nesting with spinosaur sisters Deinocheirus and Sinocalliopteryx rather than like Albertosaurus, a genuine tyrannosaur. The long snout of Xiongguanlong does not mean it is an aberrant tyrannosaur. Rather it is a standard pre-spinosaur.

In the Allosaurus clade
the former tyrannosauroid, Yutyrannus now nests with the abelisaurid, Majungasaurus, among tested taxa. They both share a median nasal crest absent in Allosaurus, but retained by Ceratosaurus, Proceratosaurus and Guanlong. (But that’s not all, of course). Here it is a little more difficult to lump and split due to the many convergent characters shared by unrelated giant theropods. In Yutyrannus the skull is larger relative to the shorter neck, for instance. Even so, the large forearm, and long torso stand out as starting points for uniting Yutyrannus with allosaurs. Note that Yutyrannus lacks the pinched proximal metatarsal 3 characteristic of tyrannosaur clade members. And that is not even a character in the LRT matrix.

Figure 4. Yutyrannus compared to Tyrannosaurus and Allosaurus.

Figure 4. Yutyrannus compared to Tyrannosaurus and Allosaurus. There is quite a bit of convergence here. Surprisingly, Yutyrannus is actually closer to the tiny-handed abelisaur, Majungasaurus.

 

 

 

 

It takes 30 more steps
at present to shift Yutyrannus to Tyrannosaurus (Fig. 4). That’s substantial.

Figure 2. The Dinosauria subset of the large reptile tree as of February 5, 2016. Here Proceratosaurus nests with several former long-snouted tyrannosaurs now closer to spinosaurs and allosaurs.

Figure 4. The Dinosauria subset of the large reptile tree as of February 5, 2016. Here several former long-snouted tyrannosaurs now closer to spinosaurs and allosaurs.

If a cladogram is valid,
it should recover taxa that are similar to one another both overall and in detail. One should be able to trace the evolution of character traits in a gradual fashion without having to resort the to the term ‘aberrant’ at any time, now that we have dozens of taxa to compare one to. Moreover, if a matrix is scored correctly, no matter which characters are chosen (so long as 150+ are used) all tree topologies should match. That’s the ideal. That’s not happening quite yet.

If I have made mistakes,
I will correct them when valid data becomes available that changes the tree topology. At present, however, with every added taxon, and there have been quite a few lately, the tree topology has not changed and autapomorphies are relatively rare.

 

Zhenyuanlong – A Media Blitz Missed Opportunity

Earlier we learned that the winged pre-tyrannosaur, Zhenyuanlong (Lu and Brusatte 2015, Fig. 2) was originally considered a dromaeosaur, but nests in the large reptile tree (Fig. 1) as an Early Cretaceous tyrannosaur ancestor. It is also a sister to another theropod that was once considered a dromaeosaur, Tianyuraptor (Zheng et al. 2010) and both are not far from Ornitholestes, which is basal to the four-winged pseudo-bird, Microraptor.

Figure 2. The Dinosauria subset of the large reptile tree as of February 5, 2016. Here Proceratosaurus nests with several former long-snouted tyrannosaurs now closer to spinosaurs and allosaurs.

Figure 1. The Dinosauria subset of the large reptile tree as of February 5, 2016. Here Zhenyuanlong nests with Tianyuraptor basal to Tyrannosaurus, not with dromaeosaurs.

I thought it would be interesting
to see what some of the headlines had to say at the time of the Zhenyuanlong publication announcement, none of which were critical, but simply reported the news.

You know how the media loves to add “cousin of T-rez” to their headlines.
This was a missed opportunity.

Figure 3. Zhenyuanlong reconstructed in lateral view. Something behind the pelvis could be the remains of an egg, but needs further study. Both sets of wing feathers are superimposed here. Click to enlarge.

Figure 2. Zhenyuanlong reconstructed in lateral view. Something behind the pelvis could be the remains of an egg, but needs further study. Both sets of wing feathers are superimposed here. Click to enlarge. That sure looks more like a tyrannosaur skull than a velociraptor skull. And the fact that it is longer than the cervicals and longer than half the presacrals keeps it in the tyrannosaur clade.

The original paper (Lü and Brusatte 2015)
reported“A large, short-armed, winged dromaeosaurid.”

Wikipedia
reports“Zhenyuanlong suni was a mid-sized dromaeosaurid comparable in length to the similar Tianyuraptor.”

Paleofile (National Geographic)
reports, “A cousin of the famous Velociraptor, the newly-named Zhenyuanlong belongs to a group of dinosaurs already well-known to have had protofeathers. Zhenyuanlong was large compared to other dromaeosaurs found around the same time and place, and the dinosaur had relatively shorter arms than its close relatives.  and Brusatte write, they indicate Zhenyuanlong evolved from flying ancestors and maintained the plumage through a kind of evolutionary inertia. Then again, long arm feathers can still be useful in giving dinosaurs a better grip on inclined surfaces while running as well as keeping small prey down.

Evolutionary Creationism
reports, “Is this bird kind? Is this dinosaur kind? Clearly fossils such as this break down that naive concept of kind by the fact they stubbornly refuse to fit into an arbitrary classification, which is what you would expect from a transitional fossil, after all.”

Sci-News.com
reports, “The species is a close cousin of the famous Velociraptor and is the largest dinosaur ever to have a set of bird-like wings.”

The Register
reports, “Scientists today have announced details of a newly-discovered dinosaur that was more than a bit like the dragons of legend. the skeleton depicted below represents “an aberrant and rare animal compared to the vast majority of other Liaoning dromaeosaurids, due to its large body size and proportionally tiny forearms. The dino also had a long, feathered, tail, a pronounced crest, a hairy body and decent teeth, an unusual combination that led Brusatte to give it the “fluffy feathered poodle from hell” label.”

The list of traits
Zhenyuanlong shares with tyrannosaurs vs. dromaeosaurs is here. The addition of about a dozen theropods since the addition of Zhenyuanlong to the large reptile tree has not changed the tree topology (Fig. 1). Whenever a scientist announces that a taxon is an aberrant member of one clade, it probably belongs in another clade. At least, that has been my experience so far. Earlier we looked at nine clades that produced flapping bird-like members, only one of which survived to the present.

Figure 1. Click to enlarge. Here is the subset of the large reptile tree focused on theropods. To the right are the nine taxa that took on bird-like traits.

Figure 3. Click to enlarge. Here is an earlier (now incomplete, see above) subset of the large reptile tree focused on theropods. To the right are the nine taxa that took on bird-like traits.

References
Lü J and Brusatte SL 2015. A large, short-armed, winged dromaeosaurid (Dinosauria: Theropoda) from the Early Cretaceous of China and its implications for feather evolution. Nature. Scientific Reports 5, 11775; doi: 10.1038/srep11775.

Zheng, X-T, Xu X, You H-L, Zhao Q and Dong, Z-M 2010. “A short-armed dromaeosaurid from the Jehol Group of China with implications for early dromaeosaurid evolution”Proceedings of the Royal Society B 277 (1679): 211–217.

wiki/Zhenyuanlong

 

New pterosaur website coming in 6 days: Pteros.com

A good-looking new pterosaur website
is coming soon. Pteros.com, part of the Earth Archives online organization, promises to bring you, “the most info on all known groups of the extinct flying reptiles and their environments.” Visitors are invited to vote for the next pterosaur. They are releasing a new one each week.

I’m not seeing any skeletons on the teaser
Rather the authors/artists are placing living specimens in their environs on the teaser page.

Vasika Udurawane is the lead writer. Julio Lacerda is the staff artist. Images here.

The website has contact into: nick@[their website].

Proceratosaurus: another theropod leaves the tyrannosauroids for the spinosauroids

This blogpost
continues a series of prior blogposts featuring the tested removal of taxa traditionally considered to be in the ancestry of Tyrannosaurus. Find those posts here, here, here and here. There were also a few blogposts that added non-traditional taxa to the lineage of tyrannosaurs. Find those here, here and here.

Figure 1. Only the lower 7/8 of the skull of Proceratosaurus is known. Here the skull in siitu, A tracing modified from Tracy Ford. And another tracing by Rauhut et al. 2010 with anterior and occipital views.

Figure 1. Only the lower 7/8 of the skull of Proceratosaurus is known. Here the skull in siitu, A tracing modified from Tracy Ford. And another tracing by Rauhut et al. 2010 with anterior and occipital views. Note the entire skull is concave ventrally, but the maxilla and jugal are both straight.

Proceratosaurus bradleyi
(Middle Jurassic, Bathonian, England, NHM R 4860, Fig. 1) was originally considered another Megalosaurus (Woodward 1910), then identified as a unique taxon, a likely ancestor of a another much larger and more robust horned theropod, Ceratosaurus (von Huene 1926). Those reports were made back in the day when there were very few theropods to compare with one another.

In more recent times,
Proceratosaurus was phylogenetically nested (according to Wikipedia, Angela Milner and the BBC, Rauhut et al. (2010), Loewen et al. (2013) and Brusatte et al. (2015)) as the earliest member of the tyrannosaur lineage (Figs. 2-4).

Figure 3. Theropods from Rauhut et al. 2010. Here Proceratosaurus, Dilong and Guanlong nest with tyrannosaurs.

Figure 2. Theropods from Rauhut et al. 2010. Here Proceratosaurus, Dilong and Guanlong nest with tyrannosaurs, but key taxa are missing.

The question is why do their trees and the large reptile tree differ?
The answer could be (once again) due to taxon exclusion and tradition. The shift in nestings could be due to the lack of more attractive sister taxa in traditional tyrannosaur studies. The large reptile tree includes those more attractive sister taxa. But that is not the complete answer in every case.

Figure 4. Tyrannosaurs from Brusatte et al. 2013. Some taxa nest elsewhere in the large reptile tree. Others are missing from this tree.

Figure 3. Tyrannosaurs from Brusatte et al. 2013. Some taxa nest elsewhere in the large reptile tree. Others are missing from this tree. Click to enlarge.

Could it be scoring?
I have not checked the scores and matrices in other studies. I do know that the sisters in the large reptile tree do share long lists of character traits, but D-shaped premaxillary teeth (often touted as a key trait restricted to tyrannosaurs) are not among the traits listed there. Did Spinosaurus and Suchomimus also have D-shaped premaxillary teeth? I don’t know. If not, could that trait be in their relatively short-snouted ancestors by convergence? At this point the answer is, apparently so.

Rauhut (2010 reported, “As close relationships of Proceratosaurus with several of the clades included in this analysis (coelophysoids, spinosauroids, and maniraptorans) have never been proposed previously, these clades were collapsed [individually] into [a] single operational taxonomic unit[s] (OTU[s]).” 

That’s a problem
as the large reptile tree found Proceratosaurus to nest closest to basalmost spinosauroids (former tyrannosauroids). Now do you see why it is SO important NOT to employ suprageneric taxa — ever! It is possible that Rauhut et al. (and those that followed) created their own problems by creating suprageneric taxa where they should not have done so. In Science you have to be open to any and all answers, without bias or a priori assumptions wherever practicable and possible. That’s why it is so convenient to start with the large gamut of possibilities provided by the large reptile tree (now 647 taxa and growing).

Figure 5. Theropods from Loewen et al. with pertinent taxa highlighted.

Figure 4. Theropods from Loewen et al. with pertinent taxa highlighted.

Proceratosaurus was added
to the large reptile tree (subset in Fig. 5) and it did not nest with tyrannosaurs, but with smaller Early Cretaceous taxa that traditionally nest with tyrannosaurs, but now nest with spinosaurs. Everyone agrees that Proceratosaurus nests with Guanlong and Dilong. Everyone else agrees that these three nested with tyrannosaurs (Figs. 2-4). So, I am the only unorthodox heretic at present.

Figure 2. The Dinosauria subset of the large reptile tree as of February 5, 2016. Here Proceratosaurus nests with several former long-snouted tyrannosaurs now closer to spinosaurs and allosaurs.

Figure 5. The Dinosauria subset of the large reptile tree as of February 5, 2016. Here Proceratosaurus nests with several former long-snouted tyrannosaurs now closer to spinosaurs and allosaurs.

The large reptile tree
provides ancestral taxa that share more traits (see below) with Late Cretaceous tyrannosaurs than the traditional putative Jurassic and Early Cretaceous candidates provided by the authors listed in the references. I promote these recovered candidates so they will be tested by others, as I have tested their candidate taxa.

Without a doubt,
the Late Cretaceous tyrannosaurs are all monophyletic. The question is, which taxa phylogenetically preceded them in the Early Cretaceous and Jurassic? Note that none of the taxon lists in any of the studies totally match one another. On the other hand, all of the studies are in general agreement. However, the recovered topologies don’t exactly match one another. And so the game is afoot.

Getting back to Proceratosaurus
Take a look at its sister on the allosaur branch in the large reptile tree: it’s Ceratosaurus. So maybe von Huene (1926) was on to something… or he was lucky.

Basic traits that Proceratosaurus, Guanlong and Dilong
share with Sinocalliopteryx, Deinocheirus and the spinosaurs.

  1. Long, low rostrum
  2. Sometimes smaller premaxillary teeth vs. maxillary teeth
  3. Tall orbit
  4. Premaxillary postero-lateral processes that may be present due only to the down tip of the naris.
  5. Ventral border of elongate naris formed by premaxilla + nasal
  6. Long, strongly recurved maxillary teeth
  7. Majority coverage of the quadrate by the squamosal and quadratojugal.
  8. Often, but not always, a nasal median crest.
  9. Often, but not always, a descending posterior skull relative to the maxilla

Given that
Sinocalliopteryx and Dilong had primitive feathers, all (except perhaps the giants) probably shared that rarely preserved trait. Given that the above nine traits are all skull traits, it is likely that this clade was trending toward a specific feeding niche, in this case, an aquatic one.

Someday this will all come together. 

References
Brusatte SL and Carr TD 2016. The phylogeny and evolutionary history of tyrannosauroid dinosaurs. Nature, Scientifice Reports 6 (8 pages), 20252; doi: 10.1038/srep20252.
Loewen MA, Irmis RB, Sertich JJW, Currie PJ, Sampson SD 2013. Tyrant Dinosaur Evolution Tracks the Rise and Fall of Late Cretaceous Oceans. PLoS ONE 8(11): e79420. doi:10.1371/journal.pone.0079420
Rauhut OWM, Milner AC and Moore-Fay S 2010. Cranial osteology and phylogenetic position of the theropod dinosaur Proceratosaurus bradleyi(Woodward, 1910) from the Middle Jurassic of England. Zoological Journal of the Linnean Society, published online before print November 2009. doi:10.1111/j.1096-3642.2009.00591
von Huene F 1932. Die fossile Reptil-Ordnung Saurischia, ihre Entwicklung und Geschichte. Monographien zur Geologie und Palaeontologie (Serie 1), 4: 1–361.
Woodward AS 1910. On a Skull of Megalosaurus from the Great Oolite of Minchinhampton (Gloucestershire). Quarterly Journal of the Geological Society 66: 111–115.

Amateurs: Parts 1 and 2

Part 1. Outside Paleontology
Ira Glass, host of “This American Life” from WBEZ and broadcast on NPR might have said it best, “Today on our program, amateurs, the fact that they are not professionals, that they do not play by the book, that they have time on their hands to try whatever makes it possible for them to accomplish things the pros simply never will.” Transcript here. Audio episode here.

Glass’s hypothesis has been tested here.
Do professionals have the time to look at something like 1000 taxa, reconstructing them, adding their traits to a growing matrix and promoting them? Probably not. But it needs to be done. There are many false paradigms out there… and they have been tested here.

Part 2. Inside Paleontology
The Dinosaur Mailing List brought to light the following report and later diatribe from the Leonid Schneider blog : Jingmai O’Connor (url) vs. Mickey Mortimer (url).

According to
O’Connor’s written answers to a list of printed questions published at Cell.com“Jingmai O’Connor is a Professor at the Institute of Vertebrate Paleontology and Paleoanthropology of the Chinese Academy of Sciences (IVPP), where she studies the origin and early evolution of birds. She became interested in evolution through her first mentor Donald Prothero at Occidental College, where she finished her BA in 2004. As a Graduate Student in Residence at the Los Angeles Natural History Museum she studied Mesozoic birds with Luis Chiappe, receiving a PhD in Geological Sciences from the University of Southern California in 2009. Since graduating, she has been employed by the IVPP, where she also conducted research during both undergraduate and graduate studies. Although her background is in geology, she seeks to understand feathered dinosaurs and early birds beyond their skeletons, utilizing the incredible preservation of soft tissues in Chinese Jehol fossils to try to understand the developmental and molecular mechanisms that underlie this major evolutionary transition.”

In that interview O’Connor answers this question:
What’s your view on social media and science? For example, the role of science blogs in critiquing published papers?”
“Those who can, publish. Those who can’t, blog. I understand that blogs can be useful in affording the general public insights into current science, but it often seems those who criticize or spend large amounts of time blogging are also those who don’t generate much publications themselves. If there were any valid criticisms to be made, the correct venue for these comments would be in a similar, peer-reviewed and citable published form. The internet is unchecked and the public often forgets that. They forget or are unaware that a published paper passed rigorous review by experts, which carries more validity than the opinion of some disgruntled scientist or amateur on the internet. Thus, I find that criticism in social media is damaging to science, as it is to most aspects of our culture.”

Schneider reports
“O’Connor’s last reply, to a question of academic commenting via blogs and social media, produced a Twitterstorm of indignation. Many on Twitter were debating: did O’Connor really accuse all blogging scientists of being incapable of proper academic publishing? Did she really mean to say, as Lenny Teytelman summarized it, “Good scientists publish. shitty ones blog”? Is doing both mutually exclusive?”

The rest of the Schneider blogpost
is best read in its entirety. You might think that Science is a dispassionate discipline. Not so on several fronts, as you’ll see. Some of the discussion in that blog focuses on O’Connor’s work with Chiappeavis and Mortimer’s thoughts on that paper, which I disagreed with here.

Best advice following what you’ll soon read:
Blog and bitch only when you’re sober.

 

 

Xiongguanlong: not a tyrannosauroid

I hate to keep doing this…
I know it pisses off theropod-o-philes.

A few years ago
Li, et al. 2010 described a new theropod dinosaur, Xiongguanlong, as “a longirostrine tyrannosauroid from the Early Cretaceous of China” which they nested between Eotyrannus + Dilong and Tyrannosaurus + other Late Cretaceous tyrannosaurs.

Figure 1. Xiongguanlong does not nest with tyrannosaurs, but with other long rostrum theropods, including Denocheirus and Sinocalliopteryx.

Figure 1. Xiongguanlong does not nest with tyrannosaurs, but with other long rostrum theropods, including Denocheirus and Sinocalliopteryx.

Unfortunately,
the large reptile tree nests Xiongguanlong along with other longistrine theropods, like Deinocheirus (Fig. 2), Sinocalliopteryx and the spinosaurs. I have not yet encountered any valid longirostrine tyrannosauroids. Dilong and Guanlong also nest close to these long-rostrum theropods. They were removed from the tyrannosauroids earlier here and here. Eotyrannus was likewise removed from the tyranosauroids here, and nested with Tanycologreus close to the base of the dromaeosaur/troodontid + bird split.

Figure 2. Deinocheirus skull. This long rostrum theropod nests close to Xiangguanlong and shares many traits with it.

Figure 2. Deinocheirus skull. This long rostrum theropod nests close to Xiongguanlong and shares many traits with it.

I keep hoping one of these taxa
are going to shift the tree topology back toward the traditional thinking, but each new taxon just drops into place, adding their leaf to the tree.

Figure 3. Theropod cladogram with the addition of Xiongguanlong nesting with Deinocheirus and Sinocalliopteryx.

Figure 3. Theropod cladogram with the addition of Xiongguanlong nesting with Deinocheirus and Sinocalliopteryx, not tyrannosaurs.

Li et al. report
“Xiongguanlong marks the earliest phylogenetic and temporal appearance of several tyrannosaurid hallmarks such as a sharp parietal sagittal crest, a quadratojugal with a dramatically flaring dorsal process and a flexed caudal edge, premaxillary teeth bearing a median lingual ridge, and a flaring axial neural spine surmounted by distinct processes at its corners.”

“Remarkably, Xiongguanlong has dorsally smooth nasals. Unlike the conical tooth crowns of taxa such as Tyrannosaurus, Xiongguanlong has mediolaterally compressed tooth crowns. The cervical vertebrae display only a single pair of pneumatic foramina, and the dorsal centra are not pneumatic in contrast to Albertosaurus and more derived tyrannosaurids. Xiongguanlong is remarkable in having a shallow and narrow snout forming more than two thirds of skull length…most tyrannosaur ids have short deep snouts mechanically optimized for powerful biting.”

No blame here. 
Li et al could have extended their comparative search to Sinocalliopteryx, which was published in 2007, but the skull of Deinocheirus was not published until 2014, so they are not to blame for missing such possibilities. These things happen.

References
Li D, Norell MA, Gao K-Q, Smith ND and Makovicky PJ 2010. A longirostrine tyrannosauroid from the Early Cretaceous of China. Proceedings of the Royal Society B 277:183-190.