The origin of giant birds: Phorusrhacos, the giant secretary bird

Figure 1. Phorushacids to scale. The extant Sagittarius is in color at lower right. Considering how closely Sagittarius looks like these taxa, one might be surprised to hear that Cariama (Fig. 4) is widely considered the extant relative. Cariama is not the sister in the LRT.

Traditionally
the seriema (genus: Cariama; Fig. 4) has been allied to the ‘terror’ birds, the phorusrhacids (Fig. 1), but it does not have the elevated external naris and deep beak found in the secretary bird (genus: Sagittarius, Figs. 1, 3). Sagittarius also has a more robust set of cervicals. Heretically, in the large reptile tree (LRT, 1120 taxa), the secretary bird of Africa is closer to phorusrhacids of South America.

Figure 3. Skull of Phorusrhacos, a giant terror bird in three views.

The terror-bird clade is represented in the fossil record
all the way back to the mid-Paleocene (Paleopsilopterus, no skull material known).

Figure 4. Sagittarius (secretary bird) and Cariama (seriema). While clearly related, these two nest at the base of two different major bird clades. Sagittarius is allied with terror birds. Cariama is allied with flamingo.

Sagittarius serpentarius (Miller 1779) The extant secretary bird is a chiefly terrestrial bird with long legs capable of short flights. It is a sister to Llallawavis, an ancient ‘terror bird.’

References
Alvarenga, HMF and Höfling E 2003. Systematic revision of the Phorusrhacidae (Aves: Ralliformes). Papéis Avulsos de Zoologia 43(4): 55-91.
Statius Müller PL 1776. Des Ritters Carl von Linné Königlich Schwedischen Leibarztes &c. &c. vollständigen Natursystems Supplements- und Register-Band über alle sechs Theile oder Classen des Thierreichs. Mit einer ausführlichen Erklärung. Nebst drey Kupfertafeln.Nürnberg. (Raspe).

wiki/Phorusrhacos
wiki/Sagittarius

The origin of giant birds: Gastornis (Diatryma), the giant parrot

Earlier we talked about the giant Gastornis as the sister to the parrot, Ara in the large reptile tree (LRT, 1119 taxa). Traditionally workers considered Gastornis a giant goose. Not sure why… unless they never tested Gastornis with parrots.

But first
let’s take a look at a recent paper on parrot origins, Wright et al. 2008. I came by this study while looking for fossil parrots, especially those without a descending beak tip. I did not find any. The Wright et al. study found an Australasia origin for the clade during the Cretaceous without any close relationships among modern birds.

That last conclusion is, of course, unacceptable and illogical. 
Here’s the problem: Wright’s team chose Falconiformes (Falcons), Columbiformes (pigeons and doves), Cuculiformes (cuckoos), Piciformes (woodpeckers), Coraciiformes (kingfishers), Strigiformes (owls), and Coliiformes (mousebirds) as outgroups because each was considered an ally or sister of parrots at one time or another in recent molecular phylogenetic work.

Therein lies the answer to the problem.
The large reptile tree (LRT, 1119 taxa) based on morphology nests all of these taxa far from parrots, a clade that nests with the hoatzin (Opisthocomus), the sparrow (Passer) and the chicken (Gallus) in order of increasing distance. DNA does not work over large phylogenetic distances ~ especially when sister taxa are excluded from the analysis!!

On a similar note
Bourdon and Cracraft 2011, nested Gastornis deep within the terror birds, which they mistakenly labeled, the Cariamae. I say mistakenly because the seriema, Cariama, is more closely related to flamingoes than to terror birds in the LRT, as reported earlier. This is where a wide gamut study, like the LRT, comes in handy. If Gastornis were truly a terror bird, it would have nested with them in the LRT.

Readers,
don’t guess, imagine or follow tradition or your professors when choosing your taxon list. Let an overarching study, like the LRT, guide you in your selection.

Now, on to our main topic…

Figure 1. Gastornis (=Diatryma) to scale with Ara the parrot (lower right).

Ara macao (Linneaus 1758; extant ) is the scarlet macaw. Here it nests with the giant Eocene parrot, Gastornis in the LRT. Both are among the few birds that separate the orbit from the temporal fenestrae. In parrots digit 4 (mislabeled above) extends posteriorly along with digit 1. This happens by convergence in several clades, btw.

Figure 3. Skulls of Gastornis, Brontornis and Ara, the scarlet macaw. Ara is not to scale. Brontornis is another giant parrot known from a mandible, a metatarsus and little else.

Gastornis parisiensis (Hebert 1855, Matthew et al. 1917) is one of several species, including G. (formerly Diatryma) gigantea. Derived from a sister to Opisthocomus, the hoatzin, Gastornis nests as a sister to Ara. Likely an herbivore, Gastornis had vestigial forelinmbs, cursorial hind limbs and redeveloped an upper temporal fenestra with an enlarged postfrontal, postorbital and squamosal, as in parrots. The rostrum is chiefly composed of the premaxilla, as in parrots.

Figure 4. Bird giants in the bird subset of the LRT.

References
Bourdon E and Cracraft J 2011. Gastornis is a terror bird: New insights into the evolution of the cariamae (Aves, Neornithes). Society of Vertebrate Paleontology 71stAnnual Meeting Program and Abstracts, p. 75
Cope ED 1876. On a gigantic bird from the Eocene of New Mexico. Proceedings of the Academy of Natural Sciences of Philadelphia 28 (2): 10–11.
Hébert E 1855a. Note sur le tibia du Gastornis pariensis [sic] [Note on the tibia of G. parisiensis]. C. R. Hebd. Acad. Sci. Paris (in French) 40: 579–582.
Hébert E 1855b. Note sur le fémur du Gastornis parisiensis [Note on the femur of G. parisiensis]. C. R. Hebd. Acad. Sci. Paris (in French) 40: 1214–1217.
Linnaeus C 1758. Systema naturæ per regna tria naturæ, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Tomus I. Editio decima, reformata.
Matthew WD, Granger W and Stein W 1917. The skeleton of Diatryma, a gigantic bird from the Lower Eocene of Wyoming. Buletin of the American Museum of Natural History, 37(11): 307-354.
Owen R 1843. On the remains of Dinornis, an extinct gigantic struthious bird. Proceedings of the Zoological Society of London: 8–10, 144–146.
Prévost C 1855. Annonce de la découverte d’un oiseau fossile de taille gigantesque, trouvé à la partie inférieure de l’argile plastique des terrains parisiens [Announcement of the discovery of a fossil bird of gigantic size, found in the lower Argile Plastique formation of the Paris region]. C. R. Hebd. Acad. Sci. Paris (in French) 40: 554–557.
Wright TF, et al. (ten co-authors) 2008. A Multilocus Molecular Phylogeny of the Parrots (Psittaciformes): Support for a Gondwanan Origin during the Cretaceous. Molecular Biology and Evolution, 25 (10), 2141-2156 DOI: 10.1093/molbev/msn160.

wiki/Ara
wiki/Gastornis

http://scienceblogs.com/grrlscientist/2008/12/24/the-evolution-and-origin-of-pa/

 

National Geographic brings back pterosaurs: Nov. 2017

Years ago,
National Geographic (Monastersky R, May 2001?) put out an article on pterosaurs that marveled at their wonder.

This year,
National Geographic (Conniff R, Nov 2017) put out another article that was supposed to be an update, but turned out to be less than hoped. The entire article and artwork is online and it, too, marvels at their wonder. Reporter Conniff crossed the globe to visit paleontologists in the field at Big Bend National Park seeking Quetzalcoatlus, a house full of footprints in Washington DC, and  to see the latest finds in Beijing, many not yet published. The article features wonderful photographs, of course, and some great information. There was also much to criticize here.

I’m not happy with

1. the Quetzalcoatlus photo leaning on its tiny fingers and rising to a digitigrade stance. But that’s the fault of the sculptor, following Witton, etc.
2. re: Darwinopterus with egg, “evidence that for some male pterosaurs, as for some modern birds, big, brightly colored crests probably functioned as a sexual display device.” No. They found a female. Males might have been crestless in that Darwinopterus species, too. No specimen has yet been found to match “Mrs. T” but with the addition of a crest. All Darwinopterus specimens so far are specifically and/or generically distinct.
3. The gatefold artwork has several errors, including the cladogram nesting pterosaurs between crocs and dinos, deep chord wings, joined uropatagia, and a diagram of Habib’s pole-vaulting takeoff.
4. Michael Habib, reported, “They (scientific illustrators) basically take a bird model and put a membrane wing and a crest on it, but pterosaur proportions were not birdlike.” Frankly, I have never seen this. Nor do all pterosaurs have certain proportions. Nor do all birds.
5. Habib reported on the first pterosaurs arising from “light, strong reptiles adapted for running and leaping after prey. Jumping – to catch on insect or dodge a predator – evolved into ‘jumping and not coming down for a while.” He has no idea what pterosaurs are and with this sounds like a Creationist telling a ‘just so’ story lacking evidence.
6. Habib reiterated his invalid pole-vaulter hypothesis because “taking off from land with an upright, bipedal stance, as other researchers had proposed, would have shattered the femurs of larger species.” Perhaps Habib forgets that most pterosaurs, including the original ones were not ‘larger species’ and that at the same time the flapping wings were producing several times more thrust than the legs. And femurs are not prone to shatter in any tetrapods ‘doing their thing.’ On the same point, Habib reports pterosaurs often had “freakishly small feet”, (only the ornithocheirids), omitting the fact that most pterosaurs had normal feet while some, like Pterodaustro had large feet.
7. “Pterosaur wings consist of a membrane attached to each flank from shoulder to ankle”. Evidence only supports a wingtip to elbow wing membrane (Peters 2002).
8. “Changing the angle of a wrist bone called the pteroid may have given them the equivalent of the leading-edge slats on a passenger jet, for increased lift at low speeds.” No. The pteroid was relatively immobile, passively folding the propatagium whenever the wing finger was folded.
9. “The result is that pterosaurs have begun to look less like a train wreck in the sky and more like sophisticated aviators.” No animal evolves to be a train wreck, no matter how much pterosaur workers try to imagine them that way.
10. When asked about the giant heads, Habib avoided the right answer and talked about brains and hollow bones. Here Habib is quoted as calling pterosaurs, “giant flying murder heads.” Perfect for Halloween, or comedians. Not so much for the scientifically curious.
11. Following a discussion of a feud between J-C Lü and X. Wang, who went their separate ways, the following is reported: 

“We’re a very small group, and we don’t really get along,” one pterosaur specialist says. The field, says another, “has a reputation for people who viciously despise one another.” Pterosaur researcher A will readily volunteer that B is “a waste of carbon,” while C independently remarks of A that certain people “would happily see him at the bottom of the ocean.” Their combat is a natural by-product of all those optimistic hypotheses built on fragmentary evidence, and it makes the Chinese rivalry look like a tea party. Lü shrugs off talk of mutual loathing, and Wang manages to avoid talking about it at all.”

There is no reason for this to take place
or to be aired out in public. We’ve seen enough of this. It has to stop. Again, it makes all paleontologists look bad when we demean one another instead of focusing on the work itself. That being said, workers should not hold themselves up as pterosaur experts unless they can tell reporters:

1. what pterosaurs are (what animals they evolved from)
2. the only valid wing shape and stance (maybe show evidence)
3. why certain pterosaurs had big heads (often without a crest)
4. that they could not know what they know without the collections, data and analyses of their esteemed colleagues

References

Peters D 2002. A New Model for the Evolution of the Pterosaur Wing – with a twist. – Historical Biology 15: 277–301.

Nat Geo pterosaur article online here

 

 

Cyrilavis colburnorum: a mouse bird, not a stem parrot

Updated December 19, 2021 with a revision to the LRT due to adding taxa

While researching fossil parrots,
in preparation for tomorrow’s post on a giant parrot, I found a paper by Ksepka, Clarke and Grande 2011 describing a Green River “stem parrot.” Cyrilavis colburnorum (early Eocene, Fig. 1), turns out to be a primitive mouse bird, very similar to the extant Urocolius (Fig. 2)  Convergent with two tested barbets, the posterior maxilla extends lateral to and below the jawline and terminates without narrowing to a point or suturing to other bones.

FIgure 1. Skeleton of Cyrilavis in situ. This is not a parrot, but a barbet from the Green River formation.

Originally the skull was crudely traced
with an outline that failed to identify several bones and misidentified others.

The Ksepka team also failed to include
barbets in their phylogenetic analysis. Only parrots and the outgroups passeriformes, falconidae, and mouse birds in order of increasing distance.

Figure 2. Urocolius, the blue-napes mousebird, converges with parrots in having a reversible toe 4, the ability to feed upside-down and having a short, deep, hooked beak…plus that long parrot-like tail!

Like parrots,
and barbets, mouse birds sometimes have a zygodactyl (pedal digit 4 oriented posteriorly) pes (Fig. 5).

The authors discuss the clade, Halcyornithidae,
a clade within Pan-Psittaciformes. The authors report, “All character states potentially supporting halcyornithid monophyly are reconstructed as ambiguous synapomorphies due to the unresolved polytomy containing the five sampled taxa.” 

References
Feduccia A and Martin LD 1976. The Eocene zygodactyl birds of North America (Aves: Piciformes). Smithsonian Contributions to Paleontology, 27:101–110.
Ksepka DK, Clarke JA, and Grande L 2011. Stem parrots (Aves, Halcyornithidae) from the Green River Formation and a combined phylogeny of Pan-Psittaciformes. Journal of Paleontology 85:835-854

The origin of giant birds: Dinornis, the giant hoatzin

There have been several giant birds
in the fossil record (Fig. 1), and a few, like the ostrich, Struthio, are still alive today. In the next few days we’ll examine several giant birds and their smaller progenitors.

Figure 1.
Giant Dinornis compared to chicken-sized Opisthocomus to scale and similar in torso length.

Dinornis, the giant hoatzin
Dinornis maximus (Owen 1843; recently extinct; 3.6m tall), the moa, is the tallest bird that ever lived. Females were apparently distinct and larger than males. Long considered a ratite based on its resemblance to Struthio, the ostrich, here in the large reptile tree (LRT, 1119 taxa, subset Fig. 3) Dinornis nests between the hoatzin, Opisthocomus (see below) and parrots like Ara. Feather color was similar to the hoatzin, but perhaps more hair-like in substance.

Opisthocomus hoazin (Müller 1776, Hoatzin) The extant hoatzin, or stink bird, is a chiefly arboreal bird capable of short flights. A sister to Gallus and Dinornis, Opisthocomus is famous for having chicks with claws on two of the wing digits that metamorphosize into the standard fused bird hand as adults. This appears to be an atavism, or reappearance, of a trait that is lost in all other birds. The hoatzin is an herbivore. The feet are large. The taxonomic positiion of Opisthocomus has been debated, but it appears to be a primitive member of extant birds, close to the much larger Dinornis (below).

Here, another big flightless bird:

Figure 2. The extinct and flightless Cnemiornis (at right, note the little forelimbs) compared to the extant and volant Cereopsis.

This is Cnemiornis
(Fig. 3, right; Owen 1866; recently extinct; 1 m tall), the New Zealand goose, a very large and flightless goose with reduced forelimbs, reduced sternum and not much webbing between the toes. The neck is longer and pedal digit 1 is absent.

As in the unrelated Dinornis, relative to Opisthocomus,
the skull is relatively smaller, the neck is longer and has more cervicals, the dorsal neural spines are taller, the pelvis is less ossified, the forelimbs are vestiges, the patella is larger, and pedal digit 1 is smaller (actually absent in Cnemiornis).

Figure 3. Bird giants in the bird subset of the LRT.

References
Owen R 1843. On the remains of Dinornis, an extinct gigantic struthious bird. Proceedings of the Zoological Society of London: 8–10, 144–146.
Owen R 1866. XI. On Dinornis (Part X.): containing a Description of part of the Skeleton of a flightless Bird indicative of a New Genus and Species (Cnemiornis calcitrans, Ow.) Journal of Zoology 1866 The Zoological Society of London.
Statius Müller PL 1776. Des Ritters Carl von Linné Königlich Schwedischen Leibarztes &c. &c. vollständigen Natursystems Supplements- und Register-Band über alle sechs Theile oder Classen des Thierreichs. Mit einer ausführlichen Erklärung. Nebst drey Kupfertafeln.Nürnberg. (Raspe).

wiki/Hoatzin
wiki/Dinornis
wiki/Cnemiornis

Dinosaur family tree: Langer et al. responds to Baron et al. 2017 in Nature

Earlier
Baron et al. revised the dinosaur family tree by uniting Ornithischia with Theropoda to the exclusion of Herrerasaurus + Sauropodomorpha. Then Baron and Barrett 2017 moved Chilesaurus (Fig. 1) from Theropoda to Ornithischia, confirming the earlier hypothesis advanced here in 2015, but in the context of uniting Ornithischia with Sauropodomorpha (= Phytodinosauria) to the exclusion of Herrerasaurus + Theropoda.

Figure 1. Chilesaurus and kin, including Damonosaurus and basal phytodinosauria.

Today
Langer et al. 2017 argue, “we evaluate and reanalyse the morphological dataset underpinning the proposal by Baron et al.5 and provide quantitative biogeographic analyses, which challenge the key results of their study by recovering a classical monophyletic Saurischia and a Gondwanan origin for dinosaurs. Our international consortium of early dinosaur evolution specialists has come together to critically assess the Baron et al.5 dataset.”

The Langer team recovered a traditional Saurischia/Ornithischia tree, but noted it would take only 2-3 additional steps to enforce a Sauorpodomorpha/ Ornithoscelida split, as recovered by the Baron team – this after changing 2,500 scorings (10% of the dataset). The Langer team also confirmed the origin of dinos in southern Pangaea and left with three conclusions (my comments follow):

1. There is currently great uncertainty about early dinosaur relationships and the basic structure of the dinosaur family tree. Not in the large reptile tree (LRT, 1119 taxa)/
2. Dataset construction is key. No, taxon inclusion is the key. Neither the Baron team nor the Langer team included the correct outgroup taxa nor a long list of basal dinosaur taxa (see below) that direct the tree topology toward the phytodinosaur clade.
3. It is important to use appropriate computational analytical tools before making macro-evolutionary claims. No, taxon exclusion will lead to wrong results. Trait selection matters, but not as much. Scoring correctly matters, but not as much. Employing decades old software does not matter because the math and statistics are the same. Remember, only a poor workman blames his tools so don’t  blame the “computational analytical tools” for poor macro-evolutionary claims.

Bottom line:
The Langer team used the same incomplete taxon list as the Baron et al. team did. So they were looking for their ‘keys’ beneath the bright lamp, while the keys were lost in the dark alley they ignored.

This happens so often.

And
Baron et al. 2017 reply. “This  extensive re-scoring results in recovery of the ‘traditional’ topology, although with less resolution and very weak support; their result is statistically indistinguishable from the possibility that our topology provides a better explanation of the data. This weak support, despite these extensive changes, suggests that the ‘traditional’ tree struggles to account for many character distributions.”

And they disagree with many of the re-scorings. Their re-scoring of just Pisanosaurus reproduced the clade Ornithoscelida in their revised tree.

Both presented trees were poorly resolved.
The LRT is fully resolved. Baron et al. defended the possibility of a Northern origin for dinosaurs. That big ‘maybe’ does not follow the data in the LRT.

On a similar, but side note
Biology Letters was kind enough to publish my reply to the Baron and Barret 2017 paper on Chilesaurus, but much of it has bearing for today’s discussion. Here is that letter in its entirety:

Baron and Bennett [1] nest Chilesaurus [2] as the sister group to Ornithischia, rather than a tetaneuran theropod as previously proposed [2]. Unfortunately, the Baron and Bennett [1] taxon list, like the Novas et al. [2] taxon list before it, did not include many of the taxa essential to resolve this issue.

A larger study of over 1060 taxa [3] includes more taxa essential to resolve this issue. The matrix was created using MacClade [4]. Analyses were run in PAUP 4.0b10 [5] using a heuristic search and a Bootstrap/Jackknife search for 100 random addition replicates. Scores are indicated on the webpage.

On that cladogram Chilesaurus (Late Jurassic) nests as a basal ornithischian in a clade that also includes Daemonosaurus (Late Triassic) and Jeholosaurus (Early Cretaceous). The latter two taxa were not included in Baron and Bennett [1]. This clade of three taxa nested as a sister to the Sauropodomorpha with Leyesaurus at its base. The analysis recovered the clade Phytodinosauria as the sister taxa to the Theropoda. Herrerasaurus was the outgroup to these two clades as basalmost member of the Dinosauria. Basal phytodinosaurs not nesting within Sauropodomorpha + Ornithischia include Barberenasuchus, Eodromaeus, Eoraptor and Pampadromaeus.

On that cladogram Silesaurus nests within a clade Poposauridae outside the Archosauria. The clade Archosauria includes only the Crocodylomorpha + the Dinosauria. Lagerpeton nests with Tropidosuchus and other proterochampsids. The pterosaur, Dimorphodon, nests with lepidosaurs like Huehuecuetzpalli, Macrocnemus and Cosesaurus (the last of which had an antorbital fenestra by convergence [6, 7]). None of these are archosauriformes nor prolacertiformes [contra 7]. The following pertinent taxa were not included in Baron and Bennett [1]: Daemonosaurus, Jeholosaurus, Haya, Barberenasuchus, Buriolestes, Segisaurus, Procompsognathus, PVL 4597, Junggarsuchus, Pseudhesperosuchus, Carnufex, Trialestes, Gracilisuchus, Scleromochlus, Decuriasuchus, Turfanosuchus, Poposaurus, Lotosaurus, Shuvosaurus, Effigia and Tropidosuchus.

Chilesaurus was first nested as a basal ornithischian in April 2015 [8] in an earlier version of the above analysis, then with fewer taxa. With the addition of more pertinent taxa the position of Chilesaurus is indeed well resolved contra the previous e-letter [9].

1. Baron MG and Barrett PM 2017. A dinosaur missing-link? Chilesaurus and the early evolution of ornithischian dinosaurs. Biology Letters 13, 20170220.
2. Novas FE et al. 2015. An enigmatic plant-eating theropod from the Late Jurassic period of Chile. Nature 522(7556), 331.
3. http://www.ReptileEvolution.com/reptile-tree.htm .nex file link on that webpage
4. Maddison DR., & Maddison WP 2001 MacClade 4.08: Analysis of Phylogeny and Character Evolution. Version 4.03. Sinauer Associates.
5. Swofford D 2002 PAUP 4.0 b10: Phylogenetic analysis using parsimony. Sinauer Associates.
6. Ellenberger P. and de Villalta JF 1974. Sur la presence d’un ancêtre probable des oiseaux dans le Muschelkalk supérieure de Catalogne (Espagne). Note preliminaire. Acta Geologica Hispanica 9, 162-168.
7. Peters D 2000. A Redescription of Four Prolacertiform Genera and Implications for Pterosaur Phylogenesis. Rivista Italiana di Paleontologia e Stratigrafia 106 (3): 293–336.
8.https://pterosaurheresies.wordpress.com/2015/04/28/chilesaurus-new-dinos…
9. King B 2017. Chilesaurus is not a basal ornithischian. http://rsbl.royalsocietypublishing.org/content/13/8/20170220.e-letters

References
Baron MG and Barrett PM 2017. A dinosaur missing-link? Chilesaurus and the early evolution of ornithischian dinosaurs. Biology Letters 13, 20170220.
Baron MG, Norman DB and Barrett PM 2017. A new hypothesis of dinosaur relationships and early dinosaur evolution. Nature 543: 501–506;  doi:10.1038/nature21700
Baron MG, Norman DB and Barrett PM 2017. Baron et al. reply. Nature 551: doi:10.1038/nature24012
Langer et al. (8 co-authors) 2017. Untangling the dinosaur family tree. Nature 551: doi:10.1038/nature24011

Unwin 2017: Early origin of pterodactyloid bauplan

Unforunately Dr. David Unwin has brought us

1. the invalid Monofenestrata
2. Darwinopterus as the transitional taxon linking long-tails to short-tails.
3. Modular evolution
4. a 1994 continuation of the deep chord wing membrane misinterpretation of Sordes

From the Unwin 2017 abstract:
“The origin of the pterodactyloid bauplan from that of non-monofenestratan (‘rhamphorhynchoid’) pterosaurs involved extensive anatomical changes and had profound consequences for the evolutionary history of Pterodactyloidea,”

Not really. Phylogenetic analysis shows it happened gradually four times. So there is no clade. “Pterodactyloidea.” Dr. Unwin is way out of date with the latest research.

“Evolution of the pterodactyloid skull construction predates the Middle Jurassic, but remains almost completely undocumented by fossils.”

Not really. Dr. Unwin does not include a sufficient number of tiny adult pterosaur taxa. Traditionally he has ignored the tiny transitional taxa that document the origin of the pterodactyloid-grade. He does not want to accept that this grade has been attained four times and two other clades, Anurognathidae and Wukongopteridae, evolve some, but not all pterodactyloid-grade traits.

“Liaodactylus reveals that innovation in pterodactyloid skull anatomy and the appearance of derived features was well underway prior to the Upper Jurassic. Douzhanopterus, a derived NPM, demonstrates that elongation of the metacarpus and reduction of the tail and fifth toe (classic pterodactyloid synapomorphies) also predates the Upper Jurassic, but disjunction in the degree of their development across taxa is not consistent with simple explanations such as ‘adaptation for flight’. Overall, late Early to early Late Jurassic pterosaurs were much more diverse and had a far more complex evolutionary history than heretofore recognized.”

Figure 1. Douzhanopterus at top in situ compared to scale with related pterosaurs, including Jianchangopterus, Ningchengopterus and the Painten pterosaur, all at the base of the Pterodactylidae.

Not really. 
Peters 2007 recognized the ‘far more complex evolutionary history’ that Unwin has yet to accept.

Earlier we looked at Douzhanopterus (Late Jurassic) and found it nested among the primitive members of the Pterodactylus clade. Earlier we looked at Liaodactylus, which nested among the Ctenochasmatidae.

Dr. Unwin still doesn’t get the big picture
due to taxon exclusion in his analyses. Pterodactyloid-grade pterosaurs had four origins (azhdarchids and ctenochasmatids arising from Dorygnathus. Scaphognathus gives rise to pterodactylids and germanodactylids, which give rise to  tapejarids and pteranodontids. This topology has been in the literature since Peters 2007, and online since 2011 at ReptileEvolution.com. If you know Dr. Unwin, please steer him gently in that direction.

References
Unwin D 2017. The complicated and surprisingly early origin of the pterodactyloid bauplan. SVPCA-SPPC Birmingham, abstracts September 12-15, 2017.
Peters D 2007. The origin and radiation of the Pterosauria. Flugsaurier. The Wellnhofer Pterosaur Meeting, Munich 27 online here. (Please ignore the notes on Jesairosaurus and Drepanosauridae, which no longer nest with the pterosaur clade. The latest info is here and here.)
Unwin DM and Bakhurina NN 1994. Sordes pilosus and the nature of the pterosaur flight apparatus. Nature 371: 62-64.

/

A little cleanup in the bird cage, er, I mean, bird clade

Birds, as I’ve said before,
and as everyone agrees, are difficult to manage in a cladogram. But not impossible. As I learn about taxa, earlier mistakes are corrected.

Figure 1. Septencoracias, earlier nested with kingfishers, now nests with barbets, like Psilopogon in figure 2. Note the posteriorly drooping maxilla.

First up
Septencoracias morsensis (Bourdon et al., 2016; Eocene 54mya; 25 cm length; Fig. 1) is an extinct barbet, not a kingfisher, as originally identified. A tiny claw remained on manual digit 1. Note the strong resemblance to Psilopogon with the concave maxilla extending below the dentary laterally.

Figure 2. Skull of the extant barbet, Psilopogon. Note the posteriorly drooping maxilla and compare it to Septencoracias in figure 1.

Psilopogon pyrolophus (S. Müller 1836; 28 cm in length; SE Asia) is the extant fire-tufted barbet. This frugivore resides at the base of toucans + hornbills and it uses tree cavities to nest and raise chicks in.

Figure 2. Chroicocephalus, the black-headed sea gull in vivo and as a skeleton.

Second
sea gulls, like Chroicocephalus, move a little closer to hummingbirds, though still not far from kingfishers, penguins and dippers in the large reptile tree (LRT, 1119 taxa). 

Figure 3. Bird subset of the LRT showing changes mentioned above. Note: Aepyornis now nests with Struthio.

Chroicocephalus ridibundus (Linneaus 1766; 40cm long; Fig. 2) is the extant black-headed gull. It was previously listed as the genus Larus and is a gregarious, opportunistic omnivore, usually seen close to the coast. Here gulls are descendants of crows and terns, sisters to stilts + storks and basal to hummingbirds.

It’s not enough
to get a fully resolved tree or subset thereof when Bootstrap scores are less than 50 for certain nodes. To get them over 50 takes a more robust tree. Presently and provisionally there are strengths and weaknesses in birds as they are here based on generalized LRT reptile traits, rather than bird-specific traits. Working a clade like this, the cladogram tells me what traits to reexamine and why. This is still a limited taxon list, despite it’s overall size. Nevertheless and despite today’s changes, most of the LRT has  grown without the topology shifting very much.

Growing a cladogram
a taxon or two at a time is still superior to the traditional methods: 1) accepting previously published work as true and complete, then adding a new taxon; and 2) building a supertree from several previously published trees and accepting them as true and complete. Experience with the widening gamut of the LRT shows that is not often enough the case.

References
Bourdon E, Kristoffersen AV and Bonde N 2016. A roller-like bird (Coracii) from the Early Eocene of Denmark. Scientific Reports. 6. 34050. doi:10.1038/srep34050
Linneaus C von 1766. Systema naturæ per regna tria naturæ, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Tomus I. Editio duodecima, reformata. pp. 1–532. Holmiæ. (Salvius)
Müller S 1836. Reizen en onderzoekingen in den Indischen archipel, gedaan op last der Nederlandsche Indische regering, tusschen de jaren 1828 en 1836, 1857

wiki/Septencoracias
wiki/Fire-tufted_barbet

Which Hesperornis palate is correct (or better)?

Short one today.
Sometimes those who see things firsthand do not agree on what they see. Today two versions of the Hesperornis palate from the literature (Fig. 1). No photos available to DGS it. Which one is more correct?

Figure 1. Two drawings of the Hesperornis palate. Only a few parts are in agreement. Colors added for clarity.

 

New insights from the Early Cretaceous bird Changzuiornis

Figure1. Changzuiornis in situ, isolated from matrix, and repositioned to an invivo pose, each 5 seconds.

About a year and a half ago,
Huang et al. 2016 brought us a complete and articulated skeleton of a new ornithurine bird, Changzuiornis ahgmi (Fig. 1), from the Early Cretaceous very close to Yanornis. The rostrum is more elongate with a large naris and tiny teeth (Fig. 2).

Please note
the better detail DGS brings to understanding where the bones are in this crushed fossil. The original line drawing (Fig. 2 below) leaves almost everything up to the imagination.

Figure 2. Changzuiornis skull in situ showing what you can do with DGS vs. traditional tracing from the original paper.

The maxilla clearly makes up most of the rostrum
in Changzuiornis. And this came as a surprise to Huang et al., who report this is “a characteristic not present in the avian crown clade in which most of the rostrum and nearly the entire facial margin is made up by premaxilla.” (Fig. 3)

Figure 3. From Huang et al. showing in red the extent of the maxilla in their interpretations. This is not long enough according to present interpretations.

It’s actually much worse than they think.
Their interpretation (Fig. 3) of the avian crown clade rostrum is too short, at least for tested taxa like Changzuiornis and Yanornis. Huang et al. do not extend the anterior maxilla far enough anteriorly, ignoring the portion where it overlaps and laminates to the lateral premaxilla (Fig. 2). For comparison, here’s a new interpretation of Struthio, the ostrich with a larger maxilla (Fig. 4) similarly laminated to the lateral premaxilla.

If I’m wrong
I’ll gladly go through a spanking machine (a silly kid’s party game).

If that’s not enough, check out
Yanornis, Cariama, Phoenicopterus, Sagittarius, Llallawavis, Falco and Tyto for a similar anteriorly extended maxillae. All are now repaired from my earlier mistakes as I wrongly followed traditional interpretations.

Figure 3. Struthio skull with a long maxilla.

Otherwise
Changzuiornis is a close sister to Yanornis, with a longer rostrum and some other minor differences apparently a wee bit closer to Gansus, Ichthyornis and Hesperornis. For instance, pedal digits 3 and 4 are similar in length.

Speaking of Hesperornis
It’s difficult to find photographic data on the the rostrum of Hesperornis and Parahesperornis. I failed to do so because authors from Marsh to Gingreich to Martin instead provided line drawings (Fig. 4), which purported to show a tiny maxilla beneath a naris with a premaxilla forming at least half of the ventral margin of the naris. Unfortunately, no sister taxa have such a morphology. Martin 1984 let loose a clue that Parahesperornis had an anteriorly extended maxilla with that line extending anterior to the naris. I provide that option here (Fig. 4 in green) and wish for actual fossil images to work on.

Figure 4. Parahesperornis and Hesperornis skulls with a small traditional maxilla and the a new large one as interpreted here.

Ichthyornis and Gansus can’t help us.
Their skulls are too poorly known.

References
Huang J, Wang X, Hu Y-C, Liu J, Peteya JA and Clarke JA 2016. A new ornithurine from the Early Cretaceous of China sheds light on the evolution of early ecological and cranial diversity in birds. PeerJ.com
Martin L 1984. A new Hesperornithid and the relationships of the Mesozoic birds. Transactions of the Kansas Academy of Science 87:141-150.

 

wiki/Parahesperornis