Luchibang xingzhe enters the LPT… again… still not an istiodactlyid

Luchibang (Hone, Fitch, Ma and Xu 2020) is a new pterosaur from China
(Figs, 1–3) which we first learned about from a Flugsaurier 2018 abstract with photo (Hone and Xu 2018) and more recently from a pair of ‘Archosaur musings’ blogposts (links below).

Critically, Dr. Hone wrote in his blogpost:
“I didn’t include a phylogenetic analysis for a number of reasons, but notably as the specimen was so clearly an istiodactylid and their own relationships were rather unresolved, adding what was obviously a juvenile into the mix would have been a fair bit of work to not actually add any real information.” The paper includes a cladogram now, but it is heavily biased toward ornithocheirids and excludes important taxa discussed here in 2018.

Both then (233 taxa) and now (242 taxa)
with more highly resolved data the large pterosaur tree (LPT) nests Dr. Hone’s ‘young istiodactylid’ with the largest pterodactylids (Fig. 2), not istiodactylids or ornithochierids. We’ve known this for two years, so it is surprising to see this mistake perpetuated in a recent paper. Dr. Hone acknowledges the many ways in which Luchibang was ‘odd’ for an  istiodactylid: long legs, large feet, long metacarpals, short wings and a long neck.

Figure 1. The Erlianhaote specimen attributed by Hone and Xu 2018 to istiodactylidae nests in the LPT with the large derived pterodactylids.

Figure 1. The Erlianhaote specimen attributed by Hone and Xu 2018 to istiodactylidae nests in the LPT with the large derived pterodactylids.

It should be noted
that the skulls of the largest pterodactylids (Fig. 2) mimic those of istiodactylids to a remarkable degree. However, the rest of the body is distinctively different.

Figure 2. The Erlianhaote specimen nests with these pterodactylids in the LPT, not with Istiodactylus (Fig. 3). Compare to valid istiodactylids in figures 4–6/

Figure 2. The Erlianhaote specimen nests with these pterodactylids in the LPT, not with Istiodactylus (Fig. 3). Compare to valid istiodactylids in figures 4–6/

The new data from Hone et al. 2020
(Fig. 3) is more highly resolved, but the phylogenetic results are the same. Luchibang does not have the proportions of an istiodactylid, nor an ornithocheirid. Taxon exclusion might be to blame here. That, and an over reliant confidence on an earlier hunch by Dr. Hone (see quote above), a young professor known to toss out and ignore data on several previous occasions. Links can be found here, but most infamously here.

In the old days
papers would be submitted then reviewed by readers and colleagues. Nowadays, papers are reviewed prior to publication. Thereafter they may be cited, but are rarely reviewed. Dr. Hone notes that his team’s manuscript was rejected by another publication, not on the basis of its phylogenetic shortcomings, but on the suspicion that the odd proportions (for an istiodactylid) of the specimen resulted from a chimaera of unrelated pterosaur parts glued together to form a single complete specimen. That does not appear to be the case. All left and right parts are identical.

Figure 3. Istiodactylus has a shorter neck, longer wing finger and deep cristospine, among other traits not found in the new Erlianhaote specimen.

Figure 4. Istiodactylus has a shorter neck, longer wing finger and deep cristospine, among other traits not found in the new Erlianhaote specimen.

Oddly,
none of the referees mentioned in the blog posts by Dr. Hone (below) noted that Luchibang was a pterodactylid, not an istiodactylid. Unfortunately, that is the level of expertise we are dealing with out there in this topsy-turvy world, where the PhDs have no idea and thus leave it to the amateurs to do the “fair bit of work” as Dr. Hone put it (see quote above).

Also oddly,
Pterodactylus antiquus (Fig. 2) was included in the Hone et al. analysis, but did not attract Luchibang as it did in the LPT. I have not checked the scores published by Hone et al., but Hone’s own words (see above) demonstrate an initial and continuing bias toward making Luchibang an istiodactylid, despite the many traits he considered odd.

Figure 3. New tracings from Hone et al. 2020 of Luchibang (spelled Luichibang in the caption). Valid istiodactylids (see below) have much larger wings, much shorter metacarpals, much shorter necks and much smaller feet.

Figure 3. New tracings from Hone et al. 2020 of Luchibang (spelled Luichibang in the caption). Valid istiodactylids (see below) have much larger wings, much shorter metacarpals, much shorter necks and much smaller feet.

The danger from the Hone et al. paper lies in the
supposition of Hone’s team that this ‘young istiodactylid’ would grow allometrically to someday match the proportions of a full-grown istiodactylid. The Hone team does not yet realize that as tritosaur lepidosaurs, pterosaurs grow isometrically, with hatchlings having identical proportions to adults, as demonstrated by the JZMP embryo ornithocheirid.

The largest ornithocheirid

Figure 6. The unnamed largest ornithocheirid, SMNK PAL 1136

As you can see 
valid istiodactylids have much larger wings, much shorter metacarpals, much shorter necks and much smaller feet.

Figure 7. Luchibang skull in situ and reconstructed. Contra Hone et al. 2020, the cranial portion of the skull is visible and can be reconstructed.

Figure 7. Luchibang skull in situ and reconstructed. Contra Hone et al. 2020, the cranial portion of the skull is visible and can be reconstructed. The skull does resemble that of istiodactlyids by convergence, but details overlooked by the authors indicate otherwise.

Hone reported,
“apart from the back of the skull, the tail and few tiny bits, everything is there.” Using DGS methods, here (Fig. 7)  the scattered parts making up the face and back of the skull were identified, colored and reconstructed. Below (Fig. 8) the complete tiny tail is identified along with a reconstruction of the pelvis and a possible egg shell.

Figure 8. Pelvic area of Luchibang from Hone et al. 2020 with elements, including the overlooked tiny tail (green in ghosted oval) colorized. A possible egg is indicated here (blue).

Figure 8. Pelvic area of Luchibang from Hone et al. 2020 with elements, including the overlooked tiny tail (green in ghosted oval) colorized. A possible egg is indicated here (blue).

Fellow pterosaur workers…
the LPT is an open access cladogram that helps one avoid the sort of mistakes encountered by the Hone team. Coloring the bones (DGS) using layers in Photoshop is a better way to identify crushed bones. Reconstructions are essential.


References
Hone DWE and Xu 2018. An unusual and nearly complete young istiodactylid from the Yixian Formation, China. Flugsaurier 2018: the 6th International Symposium on Pterosaurs. Los Angeles, USA. Abstracts: 53–56.
Hone, DWE, Fitch AJ, Ma F, and Xu X 2020. An unusual new genus of istiodactylid pterosaur from China based on a near complete specimen. Palaeontologica Electronica 23(1):a09 Online link to PDF

https://archosaurmusings.wordpress.com/2020/03/09/a-long-overdue-welcome-to-luchibang/

https://archosaurmusings.wordpress.com/2020/03/10/ten-years-in-the-making-of-luchibang/#comment-105683

https://pterosaurheresies.wordpress.com/2018/08/11/flugsaurier-2018-young-istiodactylid-nests-with-tall-pterodactylids-in-the-lpt/

2 thoughts on “Luchibang xingzhe enters the LPT… again… still not an istiodactlyid

  1. It strikes me as odd that the body is that of Sinopterus in almost all respects. Zoom in on the images provided in Hone’s paper, and the bone colour and texture between the postranial remains and the rostrum are rather too different for my liking. One wonders if Chinese fossils forgers are getting better at their job.

    • Thanks for your comment, Dave. When you say ‘body’ can you detail that more precisely? (e.g. post-crania sans wings, torso only) Anything is possible. Pterodactylids are related to Germanodactlyids are related to sinopterids in the LPT, so perhaps the torso was conserved… to your point. In any case, the specimen is not an istiodactylid or an ornithocheirid, which referees and Hone’s team should have realized.

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