Chongmingia manus: separating those overlapping phalanges

Chongmingia zhengi 
(Wang et al. 2016; Aptian, Early Cretaceous; Figs. 1–3) is a basal bird preserving the limbs and not much else. Earlier in 2017 I did not make a reconstruction because so little was preserved. That is remedied here (Figs 1, 2). The new reconstruction of Chongmingia corrects several errors made by Wang et al. 2016.

Figure 1. Chongmingia tracing from Wang et al. alongside a reconstruction of the elements.

Figure 1. Chongmingia tracing from Wang et al. alongside a reconstruction of the elements.

Wang et al. did not separate
the overlapping phalanges (Fig. 2). Nor did they separate the overlapping coracoid and scapula (Fig. 1). Nor did they recognize the disarticulated manual unguals (Fig. 2). Nor did they realize the ‘extra’ toe phalanx was a displaced finger phalanx (Fig. 1 the white phalanx).

Figure 2. Wang et al. did not separate the overlapping phalanges or recognize the manus unguals, or recognize the extra finger phalanx displaced near the toe phalanges.

Figure 2. Wang et al. did not separate the overlapping phalanges or recognize the manus unguals, or recognize the extra toe phalanx was a displaced finger phalanx.

Chongmingia nests at the base of the scansoriopterygid clade
in the large reptile tree (LRT, 1752+ taxa subset Fig. 4). That clade includes Yi, Ambopteryx, Scansoriopteryx (Fig. 3) and other birds with a longer manual digit 3 than 2. That distinct, but not unique, morphology is nascent in Chongmingia (Fig. 3).

From the Wang et al. 2016 abstract:
“The Chinese Lower Cretaceous Jehol Group is the second oldest fossil bird-bearing deposit, only surpassed by Archaeopteryx from the German Upper Jurassic Solnhofen Limestones. Here we report a new bird, Chongmingia zhengi gen. et sp. nov., from the Jehol Biota. Phylogenetic analyses indicate that Chongmingia zhengi is basal to the dominant Mesozoic avian clades Enantiornithes and Ornithuromorpha and represents a new basal avialan lineage.”

The LRT does not support this nesting, but does place Chongmingia at a basal node, within the Scansoriopterygidae between the #12 specimen (privately owned) assigned to Archaeopteryx and Mei.

Figure 3. Ambopteryx nests midway and is phylogenetically midway between the larger Yi and the smaller Scansoriopteryx. None of these taxa have an extra long bone in the arm.

Figure 3. Ambopteryx nests midway and is phylogenetically midway between the larger Yi and the smaller Scansoriopteryx. None of these taxa have an extra long bone in the arm.

Do not overlook
the continuing fact that only three long arm bones (humerus, radius and ulna) are present in Chongmingia and other scansoriopterygid clade members (Figs. 3, 4), not four (the misidentified bat-like styliform element arising from the wrist) as other bird workers say.

Figure 4. Subset of the LRT focusing on birds. Chongmingia is highlighted in yellow in the Scansoriopterygidae.

Figure 4. Subset of the LRT focusing on birds. Chongmingia is highlighted in yellow in the Scansoriopterygidae.

I am still waiting for someone, anyone
to identify four long arm bones in any scansoriopterygid. So far, no one has.


References
Wang M, Wang X, Wang Y and  Zhou Z 2016. A new basal bird from China with implications for morphological diversity in early birds. Nature Scientific Reports 6, art. 19700, 2016.

wiki/Chongmingia

Ambopteryx enters the LRT…

…between
Yi qi and Scansoriopteryx (Fig. 1) and it is midway in size between the two. There is no controversy with that nesting.

We looked at the controversies
surrounding Ambopteryx earlier here. No one has reported a ‘stylifom’ bone in Scansoriopteryx nor any other scansoriopterygids (other than Yi qi, by mistake).

Figure 1. Ambopteryx nests midway and is phylogenetically midway between the larger Yi and the smaller Scansoriopteryx. None of these taxa have an extra long bone in the arm.

Figure 1. Ambopteryx nests midway and is phylogenetically midway between the larger Yi and the smaller Scansoriopteryx. None of these taxa have an extra long bone in the arm.

Ambopteryx longibrachium (Wang et al. 2019; Late Jurassic; IVPP V24192; 32 cm long) is a scansoriopterygid bird, a descendant of Archaeopteryx #12 (privately owned) . A dense layer of feathers is also preserved, not a bat wing, as originally described.


References
Wang M, O’Connor JK, Xu X and Zhou Z 2019. A new Jurassic scansoriopterygid and the loss of membraneous wings in theropod dinosaurs. Nature 569:256–259.

wiki/Ambopteryx

Misinterpreting Zhongornis

A few years ago
O’Connor and Sullivan 2014 took another look at a small bird-like theropod, Zhongornis, originally identified as a bird. They thought they saw “striking resemblances to both Oviraptorosauria and Scansoriopterygidae.” According to Wikipedia, “The authors reinterpreted Zhongornis as the sister taxon of scansoriopterygids, and further suggested that this clade (Zhongornis + Scansoriopterygidae) is the sister group of Oviraptorosauria.”

The original paper by Gao, et al. 2008
(O’Connor was a co-author) considered Zhongornis a bird, “the sister group to all pygostylia,” which is an invalid clade in the LRT. Several disparate clades developed pygostyles in the LRT.

Figure 4. Confuciusornithiformes to scale. Note the lack of a pygostyle in the majority of taxa.

Figure 4. Confuciusornithiformes to scale. Note the lack of a pygostyle in the majority of taxa.

By adding more relevant taxa,
in the large reptile tree (LRT, 1315 taxa) Zhongornis nested between Archaeopteryx (= Wellnhoferia) grandis and Confusciusornis (Fig. 1). Scansoriopterygids, in the LRT, are descendants of the Solnhofen bird, ‘Archaeopteryx‘ #12.

Figure 2. Zhongornis in situ.

Figure 2. Zhongornis in situ, skull reconstructiion, pes, manus and tail.

Zhongornis haoae (Gao et al. 2008; D2455; Early Cretaceous). Lack of fusion and bone texture indicate the Zhongornis holotype is a juvenile. The femoral heads and necks are not visible, perhaps not yet ossified. Even so, the wing feathers are well-develped, so the specimen is not a hatchling, but close to fledging, according to Gao et al.

Figure 3. Zhongornis pectorals as traced here and as traced by O'Connor and Sullivan (right).

Figure 3. Zhongornis pectorals as traced here and as traced by O’Connor and Sullivan (right).

The problem with the O’Connor and Sullivan paper was…
taxon exclusion. They did not test all Solnhofen birds, but considered them all Archaeopteryx and selected one to test. They did not realize that various Solnhofen birds are basal to ALL later bird clades, even those that gave up flying and grew to large to fly.

Figure 4. Zhongornis pelvic and tail area as traced here and as traced by O'Connor and Sullivan.

Figure 4. Zhongornis pelvic and tail area as traced here and as traced by O’Connor and Sullivan. The red bones are pubes. The green ones are ilia or impressions thereof.

We talk about elongate coracoids
when we talk about birds (Aves).

O’Connor and Sullivan 2014 report, “The coracoid is not well-preserved and is largely overlapped by other elements, making it difficult to confirm the original description (Gao et al., 2008) of this bone as strut-like; in DNHM D2456 it appears short, robust, and trapezoidal, a primitive morphology that characterizes oviraptorosaurs and scansoriopterygids, as well as dromaeosaurids, troodontids, Archaeopteryx and sapeornithiforms.”

In contrast
Zhongornis clearly has two elongate, barbell-shaped coracoids (Fig. 3), as in Confuciusornis.

In ReptileEvolution.com the coracoids of scansoriopterygids and Archaeopteryx have elongate coracoids. By contrast, Sapeornis and other sapeornithiforms have relatively short coracoids, reduced along with the forelimbs as the body size increased. This is sometimes called a reversal. Short coracoids can also be found in extant flightless birds.

Don’t judge or nest a taxon on just a few or a few dozen traits.
Always let the unbiased software place the taxon. To put limits on your taxon list.

References
Gao C-L, Chiappe LM, Meng Q-J, O’Connor JK, Wang X, Cheng X-D and Liu J-Y 2008. A new basal lineage of early Cretaceous birds from China and its implications on the evolution of the avian tail. Palaeontology 51(4):775-791.
O’Connor J-M and Sulivan C 2014.
Reinterpretation of the Early Cretaceous maniraptoran (Dinosauria: Theropoda) Zhongornis haoae as a scansoriopterygid-like non-avian, and morphological resemblances between scansoriopterygids and basal oviraptorosaurs. Vertebrata PalAsiatica 52(1)1–9.

wiki/Changchengornis
wiki/Confuciusornis
wiki/Zhongornis

SVP 2018: Two Yi qi abstracts still see a ‘styliform’ bone

Yi qi is the infamous scansoriopterygid
preserved in a scattered fashion (Fig. 1) in which some workers mistakenly identify a new long bone, the styliform, arising from the wrist that no other tetrapod has. Earlier one bone was identified as a displaced ulna. The other, straighter bone is a displaced and equally crushed radius. There is no such bone as a ‘styliform’.

Figure 1. Yi qi tracing of the in situ specimen using DGS method and bones rearranged, also using the DGS method, to form a standing and flying Yi qi specimen. Note the lack of a styliform element, here identified as a displaced radius and ulna.

ABSTRACT 1
Dececchi, Habib and Larsson 2018 imagine
how Yi qi could fly with that bogus styliform and only one bone in each antenbrachium. They erroneously report that among the three vertebrates with the power of flight, only one, birds (in their words: ‘paravian theropods’) “Only in this last group do we have enough of a dataset that we can begin to address the question of what is sufficient to allow flight and did it evolve more than once within the group.”

Correction.
We’ve known how pterosaurs developed wings since Peters 2000. (See how Dr. Chris Bennett’s threat has come true? “You won’t get published. And if you do get published, you won’t get cited.”)

Figure 3. Scansoriopterygidae includes two Solnhofen birds traditionally labeled Archaeopteryx, but clearly distinct genera. Note, none of these taxa have a styliform bone, as originally figured in Yi qi.
Figure 2. Scansoriopterygidae includes two Solnhofen birds traditionally labeled Archaeopteryx, but clearly distinct genera. Note, none of these taxa have a styliform bone, as originally figured in Yi qi.

The origin of bats was recovered
within the last ten years at ReptileEvolution.com and here in a four part series ending here.

Over and over this team fails
to understand what they are working with. Dececchi TA, Habib M and Larsson HC 2018 report, “Yi is different from other winged and potential volant pennaraptorans because it built its primary wing structure using a skin based membrane, as opposed to the feathered flight structure seen in birds.” This is a simple misinterpretation. Dececchi, Habib and Larsson will be more or less embarrassed when they look for the displaced antebrachia and reality dawns on them.

Moreover, due to taxon exclusion
Dececchi et al. had no idea that Yi qi and the scanoriopterygidae nest within Aves (Fig. 2), the bird clade that excludes Oviraptor and Deinonychus and includes Archaeopteryx and Passer in the large reptile tree.

Figure 1. More taxa, updated tree, new clade names.
Figure 1. More taxa, updated tree, new clade names.

ABSTRACT 2
Roy et al. 2018
also studied the soft tissue anatomy of Yi qi (Fig. 1). These authors acknowledge, “The
strange membranous wings of this animal are highly disparate from the feathered wings of
avian theropods.” They report, “In this study, all previously identified textured membrane
patches exhibited negligible fluorescence under LSF. However, for the first time, LSF
revealed multiple patches of orange-coloured suspected soft tissue around the cranial bones as well as an ungual sheath. These results appear to have two alternative explanations that deserve further investigation:

  1. differential, chemical replacement of the soft and hard
    tissues of the fossil
  2. the reported membrane patches are poorly preserved clumped
    filamentous feathers.” 

Roy et al. concluded, “The radiale angle and angle of wing abduction of Yi qi, when compared with orientations of the styliform element proposed in bat, pterosaur, maniraptoran and frog models, indicate that the maniraptoran wing model was least restrictive to bird-like folding of the wings and was probably the most likely
configuration for Yi qi.”

Distinct from most birds,
scansoriopterygids like Yi qi have a longer manual digit 3 than 2.

References
Dececchi TA, Habib M and Larsson HC 2018. Flights of fancy: modeling powered flight versus gliding in the bizarre theropod Yi qi and its bearing on the question of the origins of flight across Pennaraptora. SVP abstracts.
Peters D 2000b. A Redescription of Four Prolacertiform Genera and Implications for Pterosaur Phylogenesis. Rivista Italiana di Paleontologia e Stratigrafia 106 (3): 293–336.
Roy A, Pittman M, Kaye TG, Wang X, Xu X and Zheng X 2018. Further investigation of the soft-tissue anatomy and wing configuration of the ‘bat-winged’ pennaraptoran dinosaur Yi qi. SVP abstracts.

Pennaraptora = Oviraptor, Deinonychus, Passer, their last common ancestor and all descendants. In the LRT that clade also includes Compsognathus, T-rex, Struthiomimus and other small to giant theropods and Aorum is a sister to the last common ancestor.

Scansoriopterygidae to scale

Adding a few more scansoriopterygids
(Figs. 2, 3) to the large reptile tree (LRT, 1068 taxa subset, Fig. 4) brings us to a tipping point that needs a ‘to scale’ illustration. One is provided here (Fig. 1; click to enlarge).

Figure 1. Click to enlarge. Scansoriopterygids to scale.

Figure 1. Click to enlarge. Scansoriopterygids to scale.

These are primitive birds,
all nesting this side of the Solnhofen birds of the Late Jurassic.

Figure 1. Jeholornis curves is a smaller specimen than J. prima and differently proportioned. The two are not congeneric, but both are related scansoriopterygids.

Figure 1. Jeholornis curvipes is a smaller specimen than J. prima and differently proportioned. The two are not congeneric, but both are related scansoriopterygids.

Scansoriopterygids evolved to become
a wide variety of feathered dinosaurs, many with long tails, but a few had short stubs and long tail feathers.

Figure 2. Jeholornis prima is longer and larger than J. curvipes.

Figure 2. Jeholornis prima is longer and larger than J. curvipes.

Figure 3. Scansoriopterygidae includes two Solnhofen birds traditionally labeled Archaeopteryx, but clearly distinct genera. Note, none of these taxa have a styliform bone, as originally figured in Yi qi.

Figure 3. Scansoriopterygidae includes two Solnhofen birds traditionally labeled Archaeopteryx, but clearly distinct genera. Note, none of these taxa have a styliform bone, as originally figured in Yi qi.

Zhongjianosaurus: a tiny dromaeosaurid? No.

Wikipedia reports,
“Zhongjianosaurus yang (Xu and Qin 2017, Yixian Fm. ~60 cm in ln length; ) is a genus of dromaeosaurid belonging to the Microraptoria.”

Unfortunately
the large reptile tree (LRT) nested Zhongjianosaurus with the scansoriopterygid bird, Mei long (Fig. 1). Neither does Microraptor nest with dromaeosaurids. It nests closer to Ornitholestes. Increasing the taxon list will resolve this issue for other workers as it did here.

Figure 1. Zhongjianosaurus compared to Mei long, a scansoriopterygid bird.

Figure 1. Zhongjianosaurus compared to Mei long, a scansoriopterygid bird. Both have relatively short forelimbs vs. long hind limbs among other traits.

Xu and Qin report,
The distal carpal is represented by the compound ‘semilunate’ carpal, formed by the addition of distal carpal 4 on its ventrolateral corner, and this morphology also is present in the troodontid Mei long (Xu et al., 2014a).”

Well, 
Mei long is indeed a troodontid, but so are all birds. Better to label it a scansoriopterygid bird to avoid confusion.

When you read the PDF, bear in mind
that the authors do not label the manual digits 1–3, but 2–4 as they pay homage to Limusaurus with what I call digit 0.

Perhaps if the pelvis or skull was preserved
in Zhongjianosaurus it would nest elsewhere. At present shifting Zhongjianosaurus to Microraptor adds 6 steps. Shifting Zhongjianosaurus to Velociraptor adds 9 steps. With the given data set and character list, this is how it all shakes out at present. And, you have to admit, it’s a pretty good match!

References
Xu X; Qin Z-C 2017. A new tiny dromaeosaurid dinosaur from the Lower Cretaceous Jehol Group of western Liaoning and niche differentiation among the Jehol dromaeosaurids” (PDF). Vertebrata PalAsiatica. In press.

wiki/Zhongjianosaurus

A fresh look back at the ‘Archaeoraptor’ scandal

Updated March 3, 2018 with the updating of certain elements of these crushed fossils orient them toward Yanornis.

Earlier we looked at the ‘Archaeoraptor’ scandal under the heading “chimaeras and fakes.” Here we’ll start with a short history, then consider new discoveries and cladograms.

Figure 1. 'Archaeoraptor' in UV light from a page spread in National Geographic. When this was published it was big news.

Figure 1. ‘Archaeoraptor’ in UV light from a page spread in National Geographic. When this was published it was big news. Now such specimens have become more commonplace.


In July 1997
an unidentified Chinese farmer uncovered a rare (at that time) Early Cretaceous dinosaur with feathers (Fig. 1). During collection the plate on which the dinosaur was preserved cracked apart into a dozen or so pieces (Fig. 2). These were cemented together, but lacked feet and a tail. Nearby, from the same locality, a ‘suitable’ set of feet and tail were cemented to the plate to create a complete presentation. A year later the fossil was sold to an unidentified dealer and smuggled into the United States.

In February 1999
the feathered fossil was on display at the Tucson Gem and Mineral Show where it was purchased by The Dinosaur Museum in Blanding, Utah, USA. Artists, Stephen and Sylvia Czerkas ran the museum. A board member provided the $80,000 purchase price. Paleontologists Phil Currie and Xu Xing agreed to study the fossil.

In March 1999
Currie noticed the left and right feet (pedes) were identical: part and counterpart. ‘Improvements’ like this happen more often than one would wish with fossils that are purchased from dealers rather than extricated from a site by museum led expeditions.

Figure 1. Archaeoraptor from Rowe et al. 2000. Colored areas indicate different sources for matrix and fossils there in.

Figure 2. Archaeoraptor from Rowe et al. 2000. Colored areas indicate different sources for matrix and fossils there in.

In July 1999
CT scans were made of the fossil (Rowe et al. 2001, Fig. 2). These indicated that the bottom fragments were not part of the upper fossil, but that news did not get out until later.

In August 1999
authors Czerkas, Currie, Rowe and Xu submitted a paper to Nature on the fossil, noting that the legs and tail were composited into the slab. Nature rejected the paper. Shortly thereafter Science rejected the paper, with referees noting the illegal purchase and doctoring of the fossil.

In September 1999
Currie’s preparator concluded the fossil was a composite of 3 to 5 specimens. Again that news did not get out until later.

In October 1999
National Geographic Magazine held a press conference at which they unveiled the fossil  informally named, “Archaeoraptor,” and announced it as a transitional fossil between birds and non-bird theropod dinosaurs (which it is not, see below). Plans were also announced to return the illegally exported fossil to China.

The November 1999 issue of Nat Geo
featured the fossil in an article about dinosaur feathers (Sloan 1999, Fig. 1). Bird expert Storrs Olson criticized the pre-naming of any fossil in a popular publication without proper peer review in an academic publication. Nobody was able to ‘stop the presses’ at Nat Geo.

In December 1999 Xu Xing
sent emails to Sloan and others announcing he had found the counterpart for the tail of ‘Archaeoraptor’, but it belonged to another genus, a microraptor. Perhaps a bit to harshly, Xu Xing labeled the Nat Geo specimen a ‘fake.’

In February 2000 Nat Geo issued a press release
stating an investigation had begun and indicating the fossil may be a chimaera or a composite, something museums create. or at least used to create, on a regular basis.

In March 2000 Nat Geo published 
the forum letter from paleontologists Xu Xing suggesting that the tail did not match the rest of the body. The word ‘fake’ was replaced with ‘composite’ by the editors. And that seems  appropriate.

In April 2000 Stephen Czerkas
admitted his mistake. Others involved also expressed regret.

In October 2000 Nat Geo published 
the results of their investigation (Simmons 2000), concluding that the fossil was a composite and that most of the pertinent parties had made some mistakes.

In March 2001 Nature published
a short paper by Rowe et al. (2001) who reported on the evidence from the CT scans. They concluded that the top part was a single specimen. A second part provided the left femur, a third both tibiae, a fourth both feet and a fifth separate specimen provided the tail.

Now, here’s where it gets interesting…

In August 2002
Czerkas and Xu (2002) published an anonymously reviewed description of the fossil, renaming it Archaeovolans (Fig. 3), but it was in a self-published book, not an academic journal.

Figure 3. Archaeoraptor from Czerkas and Xu 2002 along with the original line art tracing and a new color tracing.

Figure 3. Photo of Archaeoraptor from Czerkas and Xu 2002 along with the original line art tracing and a new color tracing. Click to enlarge.

In November 2002
Zhou et al. (2002) reported the majority of the fossil belonged to the established genus Yanornis (Zhou and Zhang 2001, Fig. 4) an euornithine bird nesting basal to Ichthyornis and Hesperornis in the large reptile tree (subset in Fig. 8). Wikipedia likewise reports that Yanornis is an ornithuromorph, the clade that includes all living birds. Similarly, Zhou and Zhang considered Yanornis a member of the Ornithurae.

Figure 4. Yanornis martini holotype (IVPP V12558, Zhou and Zhang 2001) as originally traced and reconstructed by moving those traced lines back to in vivo positions.

Figure 4. Yanornis martini holotype (IVPP V12558, Zhou and Zhang 2001) as originally traced and reconstructed by moving those traced lines back to in vivo positions. This is a euornithine bird with several traits retained by living birds not shared with the STM9-52 specimen (Fig. 6).

I traced
the IVPP V12444 specimen of Archaeoraptor/ Archaeovolans/ Yanornis (Fig. 3) and created a reconstruction (Fig. 5). I did the same with the STM9-52 specimen assigned (by Zheng et al. 2014) to Yanornis (Fig. 6). The holotype of Yanornis was restored to an in vivo configuration from published tracings in Zhou and Zhang 2001 (Fig. 4). Data from all three were added to the large reptile tree (subset in Fig. 7) for phylogenetic analysis.

Figure x. Archaeovolans with legs imagined, nests with Yanornis.

Figure 5. Archaeovolans with legs imagined, nests with Yanornis.

All three taxa lump together with Yanornis
So Archaeovolans is a junior synonym for Yanornis because it is closely related.

Perhaps even more interesting
Archaeovolans is phylogenetically bracketed by taxa that have a long bony tail. So the farmer was right — but that didn’t make it right to just pull another one off the shelf.

Figure 6. Specimen STM9-52 assigned to Yanornis by Zheng et al. 2014.

Figure 6. Specimen STM9-52 assigned to Yanornis by Zheng et al. 2014.

The added foot and counter foot
are the right size, and phylogenetically close to Yanornis, too (Fig. 8). The foot and counter foot provided to Archaeovolans have traits found in ornithurine birds, like Yanornis. So, the added parts are counterfeit, based on the matrix, but correct based on the bones.

Figure 8. The foot and counter foot provided to Archaeovolans do not match those of sister taxa but more closely match those of ornithurine birds, like Yanornis.

Figure 8. The foot and counter foot provided to Archaeovolans do not match those of sister taxa but more closely match those of ornithurine birds, like Yanornis. Archaeovolans probably followed the pattern set by its sisters and would have had a relatively shorter digit 2 and digit 4.

 

 

References
Czerkas SA and Xu X 2002. A new toothed bird from China. Pp. 43-60 in Czerkas SJ. ed. 2002. Feathered Dinosaurs and the Origin of Flight. The Dinosaur Museum Journal 1. Blanding, Utah, USA.
Simons LM 2000.
 Archaeoraptor Fossil Trail. National Geographic 198 (4): 128–132.
Sloan CP 1999. Feathers for T. rex?. National Geographic 196 (5): 98–107.
Zheng X, O’Connor JK, Huchzermeyer F, Wang X, Wang Y, Zhang X, et al. 2014. New Specimens of Yanornis Indicate a Piscivorous Diet and Modern Alimentary Canal. PLoS ONE 9(4): e95036. doi:10.1371/journal.pone.0095036
Zhou Z, Clarke JA and Zhang F-C 2002. Archaeoraptor’s better half. Nature Vol. 420: 285.
Zhou Z. and Zhang F. 2001. Two new ornithurine birds from the Early Cretaceous of western Liaoning, China. Chinese Science Bulletin, 46 (15), 1258-1264.

 

Finding the foot of Yi qi

The fossil scanoriopterygid bird,
Yi qi (Xu et al. 2015) is infamous for purporting to have a long extra bone (the so-called ‘styliform element’) somehow anchored to the wrist (see below) that many experts, including Dr. Kevin Padian (2015, see below), regarded as acting like a bat finger to stretch and support a bat-like wing membrane (not feathers). No sister taxa, all of them scansoriopterygid birds, have even a hint of such a bone. Here at pterosaurheresies alone that bone was determined to be a displaced radius on one wing and a displaced ulna on the other. Without these displaced bones, the forearms do not have their radius or ulna counterpart, which is standard equipment in all tetrapods with limbs. Not sure why this went unnoticed by the experts.

On a side note,
the foot was not reconstructed because the bones were very faint and intermixed with tail bones (Fig. 1). Dr. Padian reported that nothing below the waist was known. That is incorrect. He must have been shown only one plate or counter plate.

With the recent reconstruction of a sister taxon,
Omnivoropteryx, which has an odd (autapomorphic) long pedal digit 4, a second attempt was made to trace and reconstruct the foot of Yi qi (Fig. 1). If the tracing is correct, then the reconstruction of the Yi pes greatly resembles that of it sister, Omnivoropteryx, as one would expect. However, digits 3 and 4 are similar in length. In some other scansoriopterygids, digit 4 is shorter to much shorter.

This tracing
is just about at the limit of DGS capabilities without a higher resolution dataset. Fortunately a sister taxon provides a blueprint to model this foot against. And yes, the caudal vertebrae are confusing as they mix in with the pedal elements. And yes, some of the bones are only represented by faint impressions distally and proximally with the rest filled in using a-z bracketing.

Figure 1. The foot (pes) of the scansoriopterygid bird, Yi qi, both in situ and reconstructed. The amber bones are causals.

Figure 1. The foot (pes) of the scansoriopterygid bird, Yi qi, both in situ and reconstructed. The amber bones are causals.

Back to the ‘styliform element’
Dr. Padian (2015) reports, “Their (Xu et. al) find opens two cans of worms: about interpreting unique structures in fossils and about what it means to fly. The styliform element, which may be a hypertrophied wrist bone or a neomorphic calcified structure, is longer than any of the animal’s fingers and is curved at both ends. It is probably not a true finger. How the structure is attached to the wrist is not clear, because its proximal end seems quite  squared off; this means that we also do not know if or how it could move.  What could this element be except a support for some kind of aerofoil? The authors infer this on the basis of its position and the presence of membranous tissue in the wrist area.”

Note that 
Dr. Padian does not consider the possibility that the ‘styliform element’ is either a displaced radius or ulna, despite matching lengths and morphologies. This lack of recognition is rare, but not unknown. For instance, in 2000 I did not recognize the stem of the displaced prepubis in Cosesaurus.

Fliapping
Padian also notes: “Furthermore, in flapping animals the outboard skeletal elements (wrist, hand and so on) are primarily responsible for thrust, the essential component of powered flight, but these are not particularly long in Yi qi. So, at present we can shelve the possibility that this dinosaur flapped.” This appears to be an oversight statement. Not only does Yi qi have an elongate hand, the point is: it doesn’t matter how large or feathered a forelimb is. Even flightless birds, including most baby birds, flap. However tetrapods that flap for locomotion all have locked down and elongate coracoids. Perhaps Padian meant ‘flying.” If so, he is likely correct. Scansoripterygids have been discovered with tail feathers, but not bird-like wing feathers. This may have been the first clade of flightless birds. As we learned yesterday, the dromaeosaurid, Balaur was not a basal flightless bird. If you want to see what basal flightless birds actually look like, check out the scansoriopterygids.

References
Padian K. 2015. Paleontology: Dinosaur up in the air. Nature (2015) doi:10.1038/nature14392
Xu X, Zheng X-T, Sullivan C, Wang X-L, Xing l, Wang Y, Zhang X-M, O’Connor JK, Zhang F-C and Pan Y-H 2015.
 A bizarre Jurassic maniraptoran theropod with preserved evidence of membranous wings.Nature (advance online publication)
doi:10.1038/nature14423

Omnivoropteryx reconstructed and nested

A recent addition
Omnivoropteryx sinousaorum (Czerkas & Ji 2002, Fig. 1) now nests in the large reptile tree as a sister to Epidexipteryx (Fig. 4), a derived scansoropterygid bird.

Figure 1. Omnivoropteryx reconstructed from an X-ray photograph.

Figure 1. Omnivoropteryx reconstructed from X-ray photographs (Figs. 2, 3) Some workers think this bird looks like an oviraptorid. I think it looks like an anurognathid.

From the Wikipedia article
“Omnivoropteryx
 (meaning “omnivorous wing”) is a genus of primitive flying bird from the early Cretaceous Upper Jiufotang Formation of China.

Figure 2. The Omnivoropteryx skull X-ray with DGS color tracings. These were used to reconstruct the skull in lateral view.

Figure 2. The Omnivoropteryx skull X-ray with DGS color tracings. These were used to reconstruct the skull in lateral view.

“The authors
who described Omnivoropteryx, Stephen Czerkas and Qiang Ji, stated that their specimen closely resembles Sapeornis (Fig. 5), but the pubis was longer and, since no skull was known for Sapeornis, they did not consider the two names synonyms. The later discovery of Sapeornis skulls shows that they were indeed similar to Omnivoropteryx. This may make Omnivoropteryx a junior synonym of Sapeornis, and the name may be abandoned.”

Now that you can see
the two taxa together, do you agree that they are conspecific? BTW, they nest in separate clades in the large reptile tree.

Figure 4. Omnivoropteryx shares the plate with parts of another bird.

Figure 3. Omnivoropteryx shares the plate with parts of another bird.

Omnivoropteryx was preserved
with parts of another bird (Fig. The only data I have found comes from an X-ray.

Figure 3. Epidexipteryx, another scansoriopterygid with a bird-like pelvis.

Figure 4. Epidexipteryx, another scansoriopterygid with a bird-like pelvis. The toes are not known.

Epidexipteryx (Fig. 4) is a sister
to Omnivoropteryx. Both share a long third finger. Omnivoropteryx also has a long fourth toe. Unfortunately sister taxa do not preserve the toes. This clade produced some anurognathid mimics.

Figure 4. Sapeornis does not nest as a sister to Omnivoropteryx.

Figure 5. Sapeornis does not nest as a sister to Omnivoropteryx.

Sapeornis
is basal to living birds. The scansoriopterygid clade, of course, became extinct.

References
Czerkas SA and Ji Q 2002. A preliminary report on an omnivorous volant bird from northeast China.” In: Czerkas, SJ (editor): Feathered Dinosaurs and the origin of flight. The Dinosaur Museum Journal 1:127-135.

wiki/Omnivoropteryx