Maybe the best way to compare congeneric taxa

Online presentations
have certain advantages over published books and journals. What you’ll see today could be more widely presented in the future as biology, morphology and phylogeny move from books and journals to the Internet, complete with inexpensive animation, transparency and lap dissolves.

Figure 1. GIF movie of tiger and leopard skulls for comparison. See text for details.

Figure 1. GIF movie of tiger and leopard skulls for comparison. See text for details.

Obviously related to one another,
but isolated geographically to produce distinct species, the tiger (Panthera tigris) and the leopard (Panthera pardus, Fig. 1) are interesting to compare one skull with another. A GIF movie makes comparisons easy to see. A roll-over would be easier to handle, but roll-overs are not permitted on WordPress.com sites yet.

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A giant Romanian pterosaur mandible fragment

FIgure 1. LPB R 2347 largest pterosaur mandible compared to Bakonydraco.

FIgure 1. LPB R 2347 largest pterosaur mandible compared to Bakonydraco.

Vremir et al. 2018
describe a pterosaur mandible fragment (Figs. 1, 2), “This specimen represents the largest pterosaur mandible ever found and provides insights into the anatomy of the enigmatic giant pterosaurs.”

Figure 2. LPR pterosaur mandible compared to related taxa, like Eopteranodon, and to the largest known pterosaur, Quetzalcoatlus. Figure 2. LPR pterosaur mandible compared to related taxa, like Eopteranodon, and to the largest known pterosaur, Quetzalcoatlus.

Figure 2. LPR pterosaur mandible compared to related taxa, like Eopteranodon, and to the largest known pterosaur, Quetzalcoatlus to scale.

It’s worthwhile
to place the jaw fragment in context with other pterosaurs. We don’t have a similar jaw fragment for the big Quetzalcoatlus (Fig. 2), which likely stood twice as tall as the giant eopteranodontid owner of the jaw fragment. Bakonydraco is a likely eopteranodontid, larger than Eopteranodon, but much smaller than the jaw fragment owner.

Earlier this jaw fragment was used as the basis for restoring the rest of this pterosaur as a giant azhdarchid nicknamed, ‘Dracula’ (with beaucoup errors, Fig. 2).

Figure 1. Dracula the giant azhdarchid pterosaur museum mount. Hopefully it's not too late to fix the problems here.

Figure 2. Dracula the giant pterosaur model built and based on the jaw fragment in today’s post. That’s a lot of imagination!

References
Vremir M et al. 2018. Partial mandible of a giant pterosaur from the uppermost Cretaceous (Maastrichtian) of the HaÈeg Basin, Romania. Lethaia doi: https://doi.org/10.1111/let.12268 https://onlinelibrary.wiley.com/doi/abs/10.1111/let.12268

Switching pedal phalanges on Sylviornis

According to Worthy et al. 2016
“Numerous phalanges are known for Sylviornis neocaledoniae. While no articulated material is known, the collection reveals that this bird had the usual digital formula of 2:3:4:5 for digits I to IV as shown in a composite set (Fig 11, here Fig. 1) assembled based on matching size of the elements from The Pocket, in Cave B.”

Figure 1. By switching two phalages (2.1 and 4.1) you get a pes that includes a p3.1>p2.1 as in all sister taxa. This minor change is revealed by phylogenetic analysis.

Figure 1. By switching two phalages (2.1 and 4.1) you get a pes that includes a p3.1>p2.1 as in all sister taxa. Note the red PIL intersecting the joint when repaired. This minor change is revealed by phylogenetic analysis. Image modified from Worthy et al. 2016. Cave bones, like this, can sometimes be scattered.

Sylviornis neocaledoniae (Poplin 1980, recently extinct) was originally considered a ratite, then a megapode, then a stem chicken (Gallus), not quite a meter in length. Here it nests at the base of the hook-beaked predatory birds between Sagittarius and Cariama. The premaxilla forms a crest. The narrow rostrum is mobile relative to the wide cranium. We looked at Sylviornis earlier here.

Figure 1. Sylviornis is not a giant chicken. It's a basal predatory bird.

Figure 1. Sylviornis figure with original pedal phalangeal setup.

On a similar note…
I found this skeleton of Phoenicopterus, the flamingo (Fig. 3), with its toes switched on this unknown museum mount. The preparators should have mounted digit 2 medially and digit 4 laterally.

Figure 2. Flamingo skeleton with toes switched. Pedal 2 should be medial. Pedal 4 should be lateral.

Figure 2. Beautiful flamingo skeleton with toes switched. Pedal 2 should be medial. Pedal 4 should be lateral. Science is at its best when it is both appreciative and critical.

References
Poplin F 1980. Sylviornis neocaledoniae n. g., n. sp. (Aves), ratite éteint de la Nouvelle-Calédonie. Comptes Rendus de l’Académie des Sciences, Série D (in French). 290: 691–694.
Worthy TH et al. 2016. Osteology Supports a Stem-Galliform Affinity for the Giant Extinct Flightless Bird Sylviornis neocaledoniae (Sylviornithidae, Galloanseres). PLoS ONE 11(3): e0150871. doi:10.1371/journal.pone.0150871

wiki/Sylviornis

An OpenLetter to the OpenWings Project

According to their website:
“The goal of the OpenWings Project (http://blog.openwings.org) is to understand the evolutionary history of and evolutionary relationships among birds.”

“One of our goals in this project is to collect genomic data from DNA samples that have an associated voucher specimen in a research collection.”

Figure 2. Newell's shearwater (Puffinus newelli) in vivo.

Figure 1 Newell’s shearwater (Puffinus newelli) in vivo. We’ll examine the skeleton of this bird in an upcoming blogpost. 

“The fundamental and missing piece of this otherwise powerful comparative biology toolkit is an accurate and complete avian phylogeny. The overarching goal of the OpenWings Project is to fill this gap by producing: a complete phylogeny for all 10,560 bird species that will provide a unifying framework for understanding the origins and maintenance of avian diversity… as well as serving as a case study of the benefits and challenges of sampling all species in a major clade.”

Suggestion #1:
Start with a dozen diverse birds. IF the genotypes and phenotypes produce identical tree topologies, double that number and test two dozen birds. IF those produce identical tree topologies, test four dozen birds. Etc. Etc. You’ll get to 10,560 at that rate in ten steps with confidence that your results have been validated at every step.

If at any point the genotypes and phenotypes don’t produce identical tree topologies, review your paradigms and hypothesis. There is something wrong if they don’t match. In my testing, birds genes do not recover the same tree topologies as bird traits. Don’t waste your time and money testing 10,560 bird genes only to find they don’t deliver the same tree topology as bird traits.

Suggestion #2:
Since no large scale genomic and phenomic studies of birds have ever matched, just study phenotypes. Then you can include fossils and you won’t have to exclude taxa critical to understanding the phylogeny of birds. Click here for a starter list of taxa.

I would have contacted the OpenWings Project directly,
but (at present) they don’t provide access except through apps (like Twitter) I don’t have or want.

We looked at another DNA analysis of birds
by Prum et al. 2015 here and here and found it matched dissimilar taxa while separating similar taxa. So beware of DNA. It can only be validated with trait analysis and too often it produces odd results needing odd explanations.

References
https://www.markmybird.org
http://blog.openwings.org/2018/04/10/introducing-the-openwings-project/
https://www.ReptileEvolution.com/reptile-tree.htm

More evidence for a narrow chord wing membrane in pterosaurs

Unidentified by a museum number
this beautifully complete and articulated Solnhofen (Late Jurassic) Rhamphorhynchus specimen (Figs. 1, 2) preserve outlines of soft tissue, including a narrow-chord wing membrane (supporting Zittel 1882; Schaller 1985; Peters 2002; contra Unwin and Bakhurina 1994; Elgin, Hone and Frey 2011).

Figure 1. Rhamphorhynchus specimen preserving soft tissue, including a narrow-chord wing membrane. For details see figure 2.

Figure 1. Rhamphorhynchus specimen preserving soft tissue, including a narrow-chord wing membrane. For details see figure 2.

A closer view reveals a wing-tip ungual
(Fig. 2) better presented when Photoshop increases the contrast in the photo. Note: the other wingtip is more buried. This one less so. You’re still seeing the matrix over the wingtip ungual. The preparators did not excavate the entire wingtip from either wing.

Also worthy of note:
the propatagium extends to the deltopectoral crest, not to the neck. Pedal digit 5 is not connected to the uropatagia or any other membrane. And there is no single deep chord uropatagium extending between the legs. The toes are also webbed in other specimens. Here those webs are covered by the brachiopatagium.

Figure 2. Closer view of the specimen in figure 1 with overlays showing the various membranes and wingtip ungual.

Figure 2. Closer view of the specimen in figure 1 with overlays showing the various membranes and wingtip ungual, here a little bit buried along with the tip of m4.4, probably expanding the apparent size of the wing tip, just as burying an arrowhead necessitates using more mud to cover the edges and smooth out the edges.

As documented
earlier, the deep chord wing membrane is never found in pterosaurs. Both Unwin and Bakhurina 1994 and Elgin, Hone and Frey 2011 used cartoonish outlines to fudge their data. And when Elgin, Hone and Frey 2011 could not fudge their data (e.g. the Zittel wing), their desperation to avoid confirming Peters 2002 forced them to claim ‘membrane shrinkage‘ when there was none. I’m not sugar-coating this. This is what some paleontologists do in the present age. Be ready for it when you enter this field.

Click to animate. This is the Vienna specimen of Pterodactylus, which preserves twin uropatagia behind the knees.

Click to animate. This is the Vienna specimen of Pterodactylus, which preserves twin uropatagia behind the knees.

Is this a case of confirmation bias?
Yes. But I have yet to see any examples that confirm any other interpretation. Please send them if you have them.

References
Elgin RA, Hone DWE and Frey E 2011. The extent of the pterosaur flight membrane. Acta Palaeontologica Polonica 56 (1), 2011: 99-111. doi: 10.4202/app.2009.0145
Peters D 2002. A New Model for the Evolution of the Pterosaur Wing – with a twist. – Historical Biology 15: 277–301.
Peters D 2009. A reinterpretation of pteroid articulation in pterosaurs. Journal of Vertebrate Paleontology 29:1327-1330.
Prondvai E and Hone DWE 2009. New models for the wing extension in pterosaurs. Historical Biology DOI: 10.1080/08912960902859334
Schaller D 1985. Wing Evolution. In: Hecht, M., Ostrom, J.H., Viohl, G. and Wellnhofer, P., eds, The Beginning of Birds. Proceedings of the International Archaeopteryx Conference, Eichstätt 1984, (Freundes Jura Museum, Eichstätt),pp. 333–348.
Unwin DM and Bakhurina NN 1994. Sordes pilosus and the nature of the pterosaur flight apparatus. Nature 371: 62-64.
Zittel KA 1882. Über Flugsaurier aus dem lithographischen Schiefer Bayerns. Palaeontographica 29: 7-80.

http://reptileevolution.com/pterosaur-wings.htm
http://reptileevolution.com/pterosaur-wings2.htm
http://reptileevolution.com/rhamphorhynchus-wings.htm

 

The tooth-billed pigeon Didunculus: reopening the trait/molecule argument

The rare tooth-billed pigeon
or manumea, (Didunculus strigirostris, Figs. 1, 2) is considered by Wikipedia “a large pigeon found only in Samoa. It has a large, curved, and hooked bright red bill with tooth-like projections on the lower mandible. The genus name means ‘little dodo.'” The parrot-like beak arose by convergence with parrots.

Figure 1. Skull of Didunculus compared to tracing of photo and adjusted to match.

Figure 1. Skull of Didunculus compared to tracing of photo and adjusted to match.

Shapiro et al. 2002
used DNA to nest the solitaire (Pezophaps) with the dodo (Raphus) with outgroups including the Nicobar pigeon (Caloenas), the crowned pigeon (Goura) and the tooth-billed pigeon (Didunculus (Figs 1, 2) in order of increasing distance.

Figure 2. Figures of the Didunculus skeleton.

Figure 2. Figures of the Didunculus skeleton. This taxon is transitional between ocean-going skuas and island-dwelling adzebills, and something similar was basal to dodos and solitaires.

By contrast
the large reptile tree (LRT, 1191 taxa) found Didunculus to be basal to the solitaire (Pezophaps), the dodo (Raphus) but more closely to another large flightless island bird, the adzebill (Aptornis). Pigeons, like Columba and Caloenas, nested is another clade, one that also includes the black vulture (Coragyps) and its new sister, Goura, the crested pigeon. So, once again, we have a DNA/trait mismatch. Close, but no cigar.

Figure 3. Subset of the LRT focusing on the pigeons and their kin.

Figure 3. Subset of the LRT focusing on the pigeons and their kin.

Descendants of ocean-going skuas
(genus: Catharacta) could have populated the remote and widespread islands (Fig. 4) on which many of the taxa in figure 3 can be found. I have not yet found a skua or another taxon closer to the pigeons and New World vultures, so, for now, Catharacta will have to suffice as a model. Suggestions are welcome.

Figure 4. Skuas fly from Antarctica to Alaska and probably populated the widespread remote islands on which many of the large flightless birds listed here are known, evolving in isolation.

Figure 4. Skuas fly from Antarctica to Alaska and probably populated the widespread remote islands on which many of the large flightless birds listed here are known, evolving in isolation.

The skua, Catharacta
(Fig. 5) also joins the LRT.

Figure 5. The great skua, Catharacta, is close to the ancestry of dodos, pigeons, Old World Vultures, petrels, auks and puffins.

Figure 5. The great skua, Catharacta, is close to the ancestry of dodos, pigeons, Old World Vultures, petrels, auks and puffins based on its traits.

References
Shapiro B et al. (7 co-authors) 2002. Flight of the Dodo. Science Brevia 295:1683.

https://en.wikipedia.org/wiki/Tooth-billed_pigeon

European evolution

The attached video from YouTube
shows the changing boundaries and populations of various clades of Europeans and their invading neighbors evolving over a brief amount of time: only 2417 years. You’ll witness growth, death, aggression, expansion, division, union, stasis, invasion, decay and exploration.

In evolutionary terms, Europe is a petrie dish
and we who have ancestors that lived there with rising and falling fortunes. And there is no reason to suggest that things will never change in the future. Similar videos have appeared for Asia, the world, various words, etc. etc.

Things happen.
Weather changes. Volcanoes spew. Diseases decimate. People interbreed and emigrate. Languages change. So does DNA. Sometimes education is elevated. Sometimes religion is elevated. Sometimes slaves are imported. Sometimes slaves are freed. Sometimes autocrats run amok. Sometimes cooler heads prevail.

Somehow everyone living today
had an unbroken chain of ancestors going back to tetrapods in the Devonians, chordates in the Cambrian and worms in the Ediacaran and beyond. All of this is evolution at its finest, both short term (Fig. 1) and long.