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

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A fresh look back at the ‘Archaeoraptor’ scandal

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 5. Archaevolans reconstruction. Take a look at the in situ hands. In one the metacarpals increase in length laterally. In the other metacarpals and digits 2 and 3 have changed places during taphonomy. The rest of the skeleton is scansoriotpterigid, so I went with the compact metacarpals configuration. Note the procumbent premaxilla teeth, as in Epidexipteryx.

Figure 5. Archaevolans reconstruction. Take a look at the in situ hands. In one the metacarpals increase in length laterally. In the other metacarpals and digits 2 and 3 have changed places during taphonomy. The rest of the skeleton is scansoriotpterigid, so I went with the compact metacarpals configuration. Note the procumbent premaxilla teeth, as in Epidexipteryx.

Rather than lumping all three taxa together
the cladogram split them far apart. So Archaeovolans is not a junior synonym for Yanornis nor is it closely related. Moreover, the STM9-52 specimen referred to Yanornis by Zheng et al. 2014 is not congeneric with it, but nests elsewhere on the tree based on a long list of differences.

Figure 6. Specimen STM9-52 assigned to Yanornis by O'Connor et al. but in the large reptile tree nests instead with Mei in the clade enantiornithes.

Figure 6. Specimen STM9-52 assigned to Yanornis by Zheng et al. 2014, but in the large reptile tree nests instead with the basal enantiornithine, Protopteryx. Note the enormous unfused hands, elongate sternum. lack of a pygostyle and clavicle with a stem.

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 7. Bird cladogram with the latest additions. Here the referred specimen of Yanornis nests with enantiornithes while Archaeovolans nests within the Scansoriopterygidae, not with Yanornis.

Figure 7. Bird cladogram subset of the large reptile tree with the latest additions. Here the referred specimen of Yanornis nests with enantiornithes while Archaeovolans nests within the Scansoriopterygidae, not with Yanornis. 

 

The added foot and counter foot
are the right size, but phylogenetically wrong (Fig. 8). The foot and counter foot provided to Archaeovolans have traits found in ornithurine birds, like Yanornis. The correct feet would have had a shorter digit 2, with pedal 2.1 shorter than p2.2, and probably a shorter digit 4.

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.

According to the large reptile tree
(subset in Fig. 7) the Scansorioterygidae includes at its base the Munich specimen of Archaeopteryx bavarica. Earlier we looked at the need to include several specimens of Archaeopteryx (aka Solnhofen birds) in phylogenetic analysis, because most are distinct from one another and (to my eye) not congeneric. Furthermore, several nest at the bases of the earliest bird clades.

Figure 9. Sister taxa at the base of the scansoriopterygidae include Jeholornis, Mei and Archaeovolans, here shown to scale.

Figure 9. Sister taxa at the base of the scansoriopterygidae include Jeholornis, Mei and Archaeovolans, here shown to scale.Click to enlarge. The tail was reduced in more derived scansoriopterygids, like Epidexipteryx. A relatively small pelvis is shared by all three. 

With these results
Archaeovolans can apparently keep the name that Czerkas and Xu (2002) gave it. The distinction from Yanornis seems pretty obvious. I am surprised that that old paradigm has not been busted yet.

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