The juvenile enantiornithine STM-34-1 nests with Chiappeavis in the LRT

In a paper on Early Cretaceous fossilized feather molting,
O’Connor et al. 2020 presented several specimens, among them an unnamed juvenile STM-34-1 (Figs. 1–3). The specimen originally appeared in part in Zheng et al. 2012 in their study on sternum ontogeny. O’Connor was a co-author then, too.

Figure 1. STM-34-1 in situ along with select elements.

Figure 1. STM-34-1 in situ along with select elements.

Note the shorter forelimb
and longer hind limb in the juvenile, which has no tail feathers preserved as well as those elsewhere on the body and limbs. Birds, like other archosaurs, develop allometrically, changing in shape as they mature. By contrast, pterosaurs, like other lepidosaurs, develop isometrically, not changing in shape as they mature, contra traditional thinking.

Figure 2. STM-34-1 skull in situ and reconstructed.

Figure 2. STM-34-1 skull in situ and reconstructed.

STM 34-1 is from
Liutiaogou, Ningcheng, Chifeng, Inner Mongolia, Lower Cretaceous.

Chiappeavis is from 
Jianchang, Liaoning Province, northeastern China. Jiufotang Formation, Lower Cretaceous

Figure 3. Chiappeavis, Pengornis and STM-34-1 to scale.

Figure 3. Chiappeavis, Pengornis and STM-34-1 to scale.

Added to
the large reptile tree (LRT, 1785+ taxa, subset Fig. 4) STM-34-1 nested with Chiappeavis (Fig. 3).

Figure 4. Subset of the LRT focusing on the bird clade, Enantiornithes.

Figure 4. Subset of the LRT focusing on the bird clade, Enantiornithes.

A phylogenetic analysis that tested STM 34-1
was not presented by O’Connor et al. 2020, nor by Zheng et al. 2012.


References
O’Connor JK, Falk A, Wang M and Zheng X-T 2020.
 First report of immature feathers in juvenile enantiornithines from the Early Cretaceous Jehol avifauna. Vertebrata PalAsiatica 58(1):24–44. DOI: 10.19615/j.cnki.1000-3118.190823
Zheng XT, Wang XL, O’Connor JK et al., 2012. Insight into the early evolution of the avian sternum from juvenile enantiornithines. Nat Commun, 3: 1–8.

wki/Chiappeavis

Shenqiornis: Reconstructing a Mesozoic bird skull

O’Connor and Chiappe 2011
traced (Fig. 1) and reconstructed (Fig. 2) the skull of the enantiornithine bird Shenqiornis mengi (Early Cretaceous; Wang et al. 2010; DNHM D2950-2951). This is one of the few enantiornithines with substantial skull material.

Figure 1. O'Connor et al. traced Sheqiornis like this.

Figure 1. O’Connor and Chiappe 2011 traced Shenqiornis like this.

O’Connor and Chiappe used freehand techniques
to reconstruct Shenqiornis (Fig. 2). This is almost never a good idea as assumptions and biases tend to flavor freehand reconstructions.

Figure 2. O'Connor et al. reconstructed the skull of Sheqiornis freehand.

Figure 2. O’Connor and Chiappe 2011 reconstructed the skull of Sheqiornis freehand. Missing parts are in gray, though they seem to give this bird an antorbital fossa that I don’t see and sister taxa do not have. Scale bar = 1cm.

Long time readers know, it is far better to use the DGS method
(Fig. 3) and simply transfer precisely traced shapes to the reconstruction without bias or forethought. It also permits others to see exactly what you saw in a scattered, crushed fossil.

Figure 3. The skull of Sheqiornis traced and reconstructed using DGS methods.

Figure 3. The skull of Shenqiornis traced and reconstructed using DGS methods. Compare to fig. 1 and 2. Here more bones were identified and more precisely reconstructed. Scale bar = 1 cm.

Given this data,
Sheqiornis nests with Pengornis (Fig. 4) in the large reptile tree (LRT, 1703+ taxa) based on skull traits alone.

Figure 3. Pengornis reconstructed not from tracing, but from cutting out the bones and putting them back together. Color tracing is used only for the skull elements. This holotype specimen does not have the same morphology or proportions that Chiappeavis has and it nests within the Enantiornithes.

Figure 4. Pengornis reconstructed not from tracing, but from cutting out the bones and putting them back together. Color tracing is used only for the skull elements. This holotype specimen does not have the same morphology or proportions that Chiappeavis has and it nests within the Enantiornithes.

If you think things here have been a little strange
over the last 3 weeks, you’re right. My large aging computer zapped out. Meanwhile I was able to handle posts using a small MacBook Pro, but was not able to get to my Adobe graphics software for DGS tracing and reconstructing. I was likewise unable to update the LRT. Things are back to normal now (see Fig. 3 above), so we continue!


References
O’Connor JK and Chiappe LM 2011. A revision of enantiornithine (Aves: Ornithothoraces) skull morphology. Journal of Systematic Palaeontology, 9:1, 135-157, DOI: 10.1080/14772019.2010.526639
Wang X, O’Connor J, Zhao B, Chiappe LM, Gao C and Cheng X 2010. New species of Enantiornithes (Aves: Ornithothoraces) from the Qiaotou Formation in Northern Hebei, China. Acta Geologica Sinica, 84(2):247-256.

wiki/Shenqiornis

Avimaia and her enormous egg

Bailleul et al. 2019 reported
on the posterior half of an Early Cretaceous enantiornithine bird from China, Avimaia schweitzerae (IVPP V25371, Figs. 1,2), including an enormous eggshell within her torso. The authors commented on the eggshell, which had not one, but several several layers, an abnormal condition, probably leading to the demise of the mother.

Phylogenetic analysis
The Bailleul et al. 2019 phylogenetic analysis nested Avimaia with eight most closely related taxa, of which only one, Cathayornis (Fig. 1), was also tested in the large reptile tree (LRT, 1425 taxa, subset Fig. 3) and likewise nested with Avimaia. Significantly, Cathayornis also has a very deep ventral pelvis capable of developing and expelling very large eggs.

Figure 1. Avimaia compared to Cathayornis to scale.

Figure 1. Avimaia compared to Cathayornis to scale. Cathayornis is the only other tested enantiornithine bird to have such a deep ventral pelvis.

A long, thin, straight, displaced bone was found
beneath the rib cage and identified as a rib by Bailleul et al. 2019. I wonder if it is instead a radius (Fig. 1) because it is not curved like a rib and it does not have an expanded medial process. The radius is vestigial. Regardless of the identify of this slender bone, Avimaia, appears to be ill-suited for flying based on her robust tibiae, short dorsal ribs  and giant egg. Cathayornis (Fig. 1) appears to be better-suited for flying, based on its chicken-like proportions.

Figure 2. Avimaia in situ. Some bones were originally mislabeled. Here the egg is reconstructed with a more traditional egg shape.

Figure 2. Avimaia in situ. Some bones were originally mislabeled. Here the egg is reconstructed with a more traditional egg shape.

Mislabeled bones
The right ‘pubis’ (Fig. 2) is the right ischium. The reidentified pubis has a pubic boot and the ischium does, not as in sister taxa. The authors failed to identify vestigial pedal digit 5.

The egg was originally reconstructed as a sphere (drawn as a circle) inside the abdomen. Here (Figs. 1, 2) the egg is reconstructed in a more traditional egg shape more likely to pass through the ischia and cloaca.

Figure 2. Subset of the LRT focusing on the clade Enantiornithes and the nesting of Avimaia as a derived taxon within that clade.

Figure 3. Subset of the LRT focusing on the clade Enantiornithes and the nesting of Avimaia as a derived taxon within that clade.

Most birds
lay more than one egg in a clutch. Another exceptional bird that develops a very large egg is the flightless kiwi (Apterypterx, Fig. 4).

Figure 2. Jurapteryx, Pseudocrypturus, Apteryx and Proapteryx to scale.

Figure 2. Jurapteryx, Pseudocrypturus, Apteryx and Proapteryx to scale.


References
Bailleul AM, et al. 2019. An Early Cretaceous enantiornithine (Aves) preserving an unlaid egg and probable medullary bone. Nature Communications. 10 (1275). doi:10.1038/s41467-019-09259-x
Pickrell, J 2019. “Unlaid egg discovered in ancient bird fossil”. Science. doi:10.1126/science.aax3954

wiki/Avimaia

Tiny flightless Early Cretaceous bird from Spain

Kaye et al. 2019
illuminated feathers with laser-stimulated fluorescence (Fig. 1) in a tiny, unnamed, enantiornithine bird specimen, MPCM-LH-26189 from the Las Hoyas locality (Barreminian, Early Cretaceous) of Spain. Based on the presence of those illuminated feathers and the size of the specimen (Fig. 2) the authors judged it to be a precocial hatchling, capable of walking shortly after hatching. This is the same specimen first described and not named by Knoll et al. 2018.

Figure 1. Specimen MPCM-LH-26189 a tiny enantiornithine bird in situ under white light (above, plate and counter plate) and under laser stimulated fluorescene (below). DGS colors added and used in the reconstruction in figure 2. Not sure what those red highlighted items are at lower right. See figure 2b for skull details. 

Figure 1. Specimen MPCM-LH-26189 a tiny enantiornithine bird in situ under white light (above, plate and counter plate) and under laser stimulated fluorescene (below). DGS colors added and used in the reconstruction in figure 2. Not sure what those red highlighted items are at lower right. See figure 2b for skull details.

A reconstruction of the new extra-tiny bird
is shown (Fig. 2) alongside that of another tiny coeval and closely related enantiornithine bird, Iberomesornis, to scale. Note the tiny fingers in the tiny MPCM specimen indicating flightlessness. The lower crus, distal tail and feet extend off the matrix block, so they remain unknown. Contra Kaye et al. 2019, the tiny MPCM specimen does not appear to have juvenile proportions, despite its reduced size.

Figure 2. Tiny Iberomesornis compared to scale with even tinier MPCM specimen. Note the tiny fingers. Two tibial lengths are presented since this data remains unknown. The tiny MPCM specimen does not appear to have juvenile proportions.

Figure 2. Tiny Iberomesornis compared to scale with even tinier MPCM specimen. Note the tiny fingers. Two tibial lengths are presented since this data remains unknown. The tiny MPCM specimen does not appear to have juvenile proportions.

Figure 2b. Skull of MPCM specimen traced using DGS methods and reconstructed using the resulting color parts.

Figure 2b. Skull of MPCM specimen traced using DGS methods and reconstructed using the resulting color parts.

It is always a good idea
to create a reconstruction (Fig. 2) from ‘road-kill’ taxa (Fig. 1). Such a reconstruction would have indicated the MPCM specimen did not have juvenile proportions, despite its small size… and it did not have traditional bird wings.

It is also a good idea to compare taxa
in a phylogenetic analysis to see how what you have relates to others of its kind. Here in the large reptile tree (LRT, 1423 taxa) the MPCM specimen nests close to Iberomesornis within the clade Enantiornithes.

Reversals
The MPCM specimen is the first enantiornithine to have short un-birdlike fingers (a reversal due to neotony) and such short forelimbs (another reversal).

If the tail lacked a pygostyle, as it currently appears, that would also be a reversal shared with long-tailed descendants, Pengornis and Protopteryx.

The small size of this possible adult specimen is also due to the same forces that led to tiny Iberomesornis in Early Cretaceous Spain. If the MPCM specimen had nested with much larger specimens, rather than tiny Protopteryx and Iberomesornis, then the MPCM specimen would more likely have been considered a juvenile.

Knoll et al. 2018 first studied the MPCM specimen
or its osteological correlates with other juvenile birds, not considering the possibility that phylogenetic miniaturization might make a tiny adult bird appear to be a juvenile. Perhaps that is why they concluded, “the hatchlings of these phylogenetically basal birds varied greatly in size and tempo of skeletal maturation.” Knoll et al. did not create a reconstruction nor put this specimen under phylogenetic analysis, probably on the basis of its presumed juvenile character. As your mother told you, if you assume something, you might miss out on its most intriguing aspects.

Phylogenetic analysis is so important
because it reveals so much more than just ‘eyeballing’ specimens.

Earlier we looked at other birds
that experienced a similar reversal from wings to hands. Among these are Mei long, Jinianhualong and Liaoningvenator.

In the Late Jurassic
tiny pterosaurs experienced a similar size squeeze. Traditionally considered juveniles, tiny hummingbird-sized taxa like B St 1967 I 276 (Fig. 3) and BMNH 42736 with fly-sized hatchlings, were among the few pterosaur lineages to survive the Jurassic and produce Cretaceous taxa.

From NatGeo.com
Paleo bird expert, Jingmai O’Connor reports, “All enantiornithines were super-precocial, born fully-fledged and ready to fly.”

A closer examination
indicates the MPCM specimen was never going to be ‘ready to fly.’ 

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 3. Smallest known bird, the 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.

Is the MPCM specimen the smallest dinosaur?
If it is an adult, the MPCM specimen appears to be slightly larger than the smallest known dinosaur, the bee hummingbird (Fig. 3).

Since no one else wants to name the MPCM specimen,
probably because others considered this a hatchling rather than a phylogenetically miniaturized adult, let’s call him Microcursor sanspedes (‘tiny runner without feet”) in the meantime.


References
Kaye TG, Pittman M, Marugán-Lobón J, Martín-Abad H, Sanz JL and Buscalioni AD 2019. Fully fledged enantiornithine hatchling revealed by Laser-Stimulated Fluorescence supports precocial nesting behavior. Nature.com/scientific reports (2019) 9:5006 https://doi.org/10.1038/s41598-019-41423-7

Knoll, F. et al. (16 co-authors) 2018. A diminutive perinate European Enantiornithes reveals an asynchronous ossification pattern in early birds. Nature Communications 9, 937 (2018).

Publicity

https://www.nationalgeographic.com/science/2019/03/dinosaur-era-birds-born-ready-to-run-fossil-feathers-show/

The tail feathers of Chiappeavis. The coracoid of Jianianhualong.

An exercise in DGS today
(digital graphic segregation, Fig. 1). It’s okay to increase the contrast in a fossil photo. That’s not considered ‘manipulating’ the data, but enhancing it, like using a magnifying glass of a colored filter.

Figure 1. GIF animation of the a photograph of the tail of Chiappeavis from O'Connor et al. 2016. Original tracing is included in this series.

Figure 1. GIF animation of the a photograph of the tail of Chiappeavis from O’Connor et al. 2016. Original tracing is included in this series. Photoshop was used to increase contrast.

Chiappeavis magnapremaxillo (O’Connor et al. 2016, Early Cretaceous; Figs. 1-2) is a basal enantiornithine bird with a pygostyle. The short tail was tipped with a fan of feathers. The forelimbs were relatively larger than in related taxa.

Figure 2. Chiappeavis with a shorter premaxillary ascending process and no metatarsal 5. Some small changes make big differences. Pengornis is shown to scale.

Figure 2. Chiappeavis with a shorter premaxillary ascending process and no metatarsal 5. Some small changes make big differences. Pengornis is shown to scale. The elongate corticoids were not scored in the LRT matrix.

Error amended.
Earlier I nested Chiappeavis between the Eichstaett specimen of Archaeopteryx recurva and Jianianhualong, the large troodontid-like, flightless bird of the Early Cretaceous. Then a red flag appeared. The problem was: short-tailed Chiappeavis did not belong between two long-tailed taxa. That has been repaired in the large reptile tree (LRT) and Chiappeavis has been nested appropriately as it was originally nested by O’Connor et al., with Pengornis (Fig. 2). And now there is no intervening short-tailed taxon between the small Archaeopteryx and the large Jianianhualong, both with long tails.

Figure 3. Jianianhualong and Archaeopteryx recurva to scale.

Figure 3. Jianianhualong and Archaeopteryx recurva to scale. Both are birds. Jianianhualong is the earliest known large flightless bird, and it retained asymmetrical flight feathers.

The first Big Bird
was Jianianhualong. Larger than its closest kin and definitely flightless, Jianianhualong retained asymmetrical flight feathers. It also had a coracoid nearly identical to that found in Sapeornis (Fig. 4). Jianianhualong had a reduced vestige of the large perching pedal digit 1 found in basal volant birds.

Two specimens attributed to Sapeornis, that nest together in the LRT. IVPPP V13276 is larger and more robust. DNHM-F3078 has a juvenile bone texture. Gao et al 2012 considered these two conspecific.

Figure 4. Two specimens attributed to Sapeornis, that nest together in the LRT. IVPPP V13276 is larger and more robust. DNHM-F3078 has a juvenile bone texture. Gao et al 2012 considered these two conspecific.

The cladogram of birds
has been updated with the addition of taxa (Fig. 5).

Figure 5. Subset of the LRT focusing on the bird cladogram.

Figure 5. Subset of the LRT focusing on the bird cladogram.

References|
O’Connor JK, Wang X-L, Zheng X-T, Hu H, Zhang X-M and Zhou Z 2016.
An Enantiornithine with a Fan-Shaped Tail, and the Evolution of the Rectricial Complex in Early Birds.Current Biology (advance online publication) DOI: http://dx.doi.org/10.1016/j.cub.2015.11.036

Chongmingia: no longer an enigma bird

Revised November 1, 2020
with a reconstruction of Chongmingia (Fig. 1) with new insights into to pectoral girdle and manus along with a new nesting near the base of the scansoriopterygidae in the LRT (subset Fig. 2) close to Mei and Yi (Fig. 3).

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. 2016
reported on a head-less, ‘tail-less’ basal bird fossil, which they named Chongmingia (Fig. 1).

Unfortunately the team had some difficulty nesting Chongmingia.
They reported: “For the first analysis using the coelurosaurian matrix, the analysis produced 630 most parsimonious trees of 4523 steps (Consistency index = 0.266, Retention index = 0.578). The strict consensus tree placed Chongmingia within basal Avialae, and Chongmingia is the sister taxon of Ornithothoraces. For the second analysis focusing on phylogeny of Mesozoic birds, the analysis produced four most parsimonious trees of 1009 steps. The strict consensus tree places Chongmingia as the sister to all avialans except for Archaeopteryx, and thus Chongmingia represents the most primitive bird from the Jehol Biota uncovered to date and one of the most primitive Cretaceous birds known. However, this phylogenetic hypothesis was weakly supported by both Bremer and Bootstrap values.”

Unfortunately the team did not use several Solnhofen birds 
in their phylogenetic analysis. Perhaps if they did so, like the large reptile tree (LRT, 998 [now 1752] taxa) does, then they might have recovered a single tree in which Chongmingia nests within basal Scansoriopterygidae in the LRT (Fig. 2).

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 was able to see in the published photo of Chongmingia

  1. a small string of diminishing caudal vertebrae
  2. the scapula and coracoid intertwined
  3. reidentified some disarticulated phalanges
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.

Nesting at the base of the derived taxa,
Mei, Yi, and the several other scansoropterygids with a longer manual 3 than 2, Chongmingia (Fig. 1) is the first step toward that morphology. AND… there is no hint of a new, elongate carpal bone. That mistake remains a myth.

Such a small tail
like the similarly short-changed Yi, would not have accommodated many rectrices (tail feathers). There is no evidence of a pygostyle. Relatives don’t have a pygostyle.


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

The geologically oldest Archaeopteryx (#12)

Updated November 10, 2016 with higher resolution images of the specimen. The new data moved the taxon over by one node. 

Not published yet in any academic journal,
but making the news in the popular press in Germany to promote a dinosaur museum (links below) is the geologically oldest Archaeopteryx specimen (no museum number, privately owned?). Found by a private collector in 2010, the specimen has been declared a Cultural Monument of National Significance. It is 153 million years old, several hundred thousand years older than the prior oldest Archaeopteryx. It is currently on  display at a new museum, Dinosaurier-Freiluftmuseum Altmühltal in Germany, about 10 kilometers from where the fossil was found.

Figure 1. The new oldest Archaeopteryx in situ with color tracings of bones.

Figure 1. The new oldest Archaeopteryx in situ with color tracings of bones. The ilium has been displaced to the posterior gastralia, or is absent. I cannot tell with this resolution.

Figure 1b. Archaeopteryx 12 in higher resolution.

Figure 1b. Archaeopteryx 12 in higher resolution.

So is it also the most primitive Archaeopteryx?
No. But it nests as the most primitive scansioropterygid bird. As we learned earlier, the Solnhofen birds formerly all considered members of the genus Archaeopteryx (some of been subsequently recognized by certain authors as distinct genera) include a variety of sizes, shapes and morphologies (Fig. 3) that lump and separate them on the large reptile tree. The present specimen has been tested, but will not be added to the LRT until it has a museum number or has been academically published (both seem unlikely given the private status). Given the additional publicity the specimen is now in the LRT.

The fossil is wonderfully complete and articulated
and brings the total number of Solnhofen birds to an even dozen.

This just in
Ben Creisler reports, “The fossil specimen was originally found in 2010 in fragmented condition and took great effort to prepare and piece together as it now appears.”

Figure 2. Reconstruction of the geologically oldest Archaeopteryx, now nesting at the base of the Scansoriopterygidae.   Note the large premaxillary teeth and short snout on a relatively small skull.

Figure 2. Reconstruction of the geologically oldest Archaeopteryx, now nesting at the base of the Scansoriopterygidae. Note the large premaxillary teeth and short snout on a relatively small skull.

Compared to other Archaeopteryx specimens
you can see the new one is among the smallest (Fig. 3) and has a distinct anatomy.

Figure 2. Several Archaeopteryx specimens. The geologically oldest one, (at bottom) is among the smallest and most derived, indicating an earlier radiation than the Solnhofen formation.

Figure 2. Several Archaeopteryx specimens. The geologically oldest one, (at bottom) is among the smallest and most derived, indicating an earlier radiation than the Solnhofen formation.

References
Spektakulaerer-Fund-kommt-in-Ausstellung-article
originalskelett-eines-archaeopteryx-zu-sehen.html
auf-zum-archaeopteryx

Website

Tiny Iberomesornis

Figure 1. Iberomesornis revisited. One of the smallest of the enantiornithes birds has a long pedal digit 4.

Figure 1. Iberomesornis revisited. One of the smallest of the enantiornithes birds has a long pedal digit 4. Note the placement of the longest toe beneath the center of balance at the shoulder glenoid in this volant biped, a configuration convergent with pterosaurs.

Iberomesornis romerali (Sanz and Bonaparte 1992, LH-22 (Las Hoyas Collection), Barremian, Early Cretaceous, 125 mya) tiny bird (8.7 cm axial column) with short wings (20 cm wingspan), pygostyle.  The long coracoids indicated powerful flapping muscles. The combination of a long p4.4 and short p3.3 makes the foot unique. This tiny taxon continued the phylogenetic size reduction that coincided with improvements in the ability to fly, as indicated by the longer coracoids and caudal fusion.

The Enanitornithes, or opposite birds, are so-named because their scapula/coracoid joint tabbed the opposite way of living birds. No living birds are enantiornithes.

References
Sanz JL and Bonaparte JF 1992. A New Order of Birds (Class Aves) from the Lower Cretaceous of Spain. In JJ Becker (ed): Papers in Avian Paleontology Honoring Pierce Brodkorb. Natural History Museum of Los Angeles County Contributions in Science 36:38-49

wiki/Iberomesornis

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.

 

Jim Hopson (U. Chicago) awarded Romer-Simpson Medal

Jim Hopson, Professor Emeritus, University of Chicago, honored with the Romer-Simpson medal at the Dallas 2015 meeting of the Society of Vertebrate Paleontology. Well deserved.

Jim Hopson, Professor Emeritus, University of Chicago, honored with the Romer-Simpson medal at the Dallas 2015 meeting of the Society of Vertebrate Paleontology. Well deserved.

I’m happy to report
that Jim Hopson has been awarded the highest honor the Society of Vertebrate Paleontology can bestow, the Romer-Simpson Medal for a lifetime of achievement.

Hopson focused his research
on the origin of mammals. His work indicated that mammals descended from a single lineage of mammal-like reptiles. His work on tooth replacement in mammal-like reptiles was one of the first to show that growth patterns and dental anatomy can be used to study these extinct species.

On the side
Hopson served as the expert editor for my book, “From the Beginning, the Story of Human Evolution” (Peters 1991). Shortly thereafter, in the late 80s Dr. Hopson was kind enough to host my field trip to Chicago. He showed me the collections there and at the Field Museum. Dr. Hopson also provided reams of photocopies of his work on synapsids. Much of that went into the book, which remains largely accurate today. You can read the book online in PDF form here.

Figure 1. From the Beginning - The Story of Human Evolution was published by Little Brown in 1991 and is now available as a FREE online PDF from DavidPetersStudio.com

From the Beginning – The Story of Human Evolution published by Little Brown in 1991 and is now available as a FREE online PDF from DavidPetersStudio.com by clicking here.

However, the latest
cladograms and basal mammal studies can be found at ReptileEvolution.com.

Read more
about Jim Hopson and his contributions to vert paleo here.

A note about the Liaoning bird embryo from a few days ago…
Dr. Zhou was kind enough to send a high resolution image of the specimen and I have updated the imagery and conclusions posted here on the Liaoning bird embryo. In short, the embryo now nests with the holotype (London specimen) of Archaeopteryx, which nested and still nests as a basal enantiornithine bird. Happily, this analysis confirms both the original identification of the embryo as an enantiornithine, AND a close relationship to Archaeopteryx. 

High resolution will get you there,
but low resolution can still get you close…