Palaelodus: transitional between flamingos and grebes?

A short break from our Prum et al. 2015 series
as we take a peek at the origin of flamingos and other basal neognath birds, which we’ll look at in greater depth tomorrow in part 3.

Traditionally
flamingos, like Phoenicopterus (Fig. 1), have been difficult to nest in bird cladograms. Flamingos seem to stand alone. Bird expert Gerald Mayr 2004 quoted Sibley & Ahlquist (1990), who wrote flamingos are “among the ‘most controversial and long-standing problems’” in phylogenetic analysis.

Bird expert
Cracraft (1981) made a luke-warm suggestion for stork affinities. Other bird experts, Olson and Feduccia (1980) liked stilts and avocets as relatives. They also suggested that flamingo-like Palaelodus (Figs. 2, 3) ‘may have occupied a more duck-like swimming niche than do typical flamingos’, The Galloanseres (chickens + ducks invalid clade) was considered, perhaps based on the long-legged duck Presbyornis.

Using molecules,
Prum 2015 and others before them nested the flamingo, Phoenicopterus, with the flightless grebe, Rollandia (Fig. 1). And now (hopefully) you see what I mean when I say, DNA does not recover testable or valid relations over long phylogenetic distances.

Figure 1. The flamingo, Phoenicopterus, compared to the grebe, Rollandia. DNA says these two are more closely related than any other tested taxa. The LRT reports they are not related.

Figure 1. The flamingo, Phoenicopterus, compared to the grebe, Rollandia. DNA says these two are more closely related than any other tested taxa. The LRT reports they are not related.

Using morphology
the large reptile tree, (LRT, 1026 taxa) nests the flamingo with the similarly proportioned, hook-beaked seriema, Cariama sisters to the terrestrial birds of prey, represented today by Sagittarius, the secretary bird. Here (Fig. 2), based on a long list of shared traits, it is possible to see how flamingos could gradually arise from seriemas.

Figure 2. Which taxa share more traits? Phoenicopterus, the flamingo nests with Cariama, the seriema in the LRT, but with Gavia in the Prum et al. DNA study. Gavia nests with Thalasseus, the tern in the LRT.

Figure 2. Which taxa share more traits? Phoenicopterus, the flamingo nests with Cariama, the seriema in the LRT, but with Gavia in the Prum et al. DNA study. Gavia nests with Thalasseus, the tern in the LRT.

Mayr 2004 wrote:
“A recent molecular analysis strongly supported sister group relationship between flamingos (Phoenicopteridae) and grebes (Podicipedidae), a hypothesis which has not been suggested before. Flamingos are long-legged filter-feeders whereas grebes are morphologically quite divergent foot-propelled diving birds, and sister group relationship between these two taxa would thus provide an interesting example of evolution of different feeding strategies in birds.”

Morphologicaly,
grebes are quite similar to loons, like Gavia (Fig. 2), which nests with terns and penguins in the Prum et al. tree AND in the LRT. (Wow! That’s a rare happenstance!)

Then Mayr 2006
found a taxon that had been around awhile Palaelodus ambiguus (Figs. 3–5), that morphologically linked flamingos to grebes. Mayr reports, “Since both grebes and †Palaelodidae are aquatic birds which use their hindlimbs for propulsion, it is most parsimonious to assume that the stem species of (Pan-)Phoenicopteriformes also was an aquatic bird which used its hind limbs for propulsion in the water (Mayr 2004). Palaelodus has “derived skull features of flamingos with leg adaptations for hindlimb propulsion found in grebes.”

Figure 3. From Mayr 2006, who wrote, "Palaelodus sp. (†Palaelodidae; uncatalogued specimen from Alliers in France in the collection of Forschungsinstitut Senckenberg). Note that the upper beak and part of the cranium in B are reconstructed."

Figure 3. From Mayr 2006, who wrote, “Palaelodus sp. (†Palaelodidae; uncatalogued specimen from
Alliers in France in the collection of Forschungsinstitut Senckenberg). Note that the upper beak and part of the cranium in B are reconstructed.”

In the LRT
stork-like Palaelodus (1.5m tall) nests with Rhynchotus, a tinamou. Like Rhynchotus, Palaelodus appears to be fully volant.

Figure x. Data used to score Palaelodus in the LRT. Note the very flamingo-like proportions, but this is a ratite.

Figure 4. Data used to score Palaelodus in the LRT. Note the very flamingo-like proportions, but this is a tall, gracile tinamou.

70 characters and 17 suprageneric taxa later, Mayr 2004 wrote:
“Previously overlooked morphological, oological and parasitological evidence is recorded which supports this hypothesis, and which makes the taxon (Podicipedidae + Phoenicopteridae) one of the best supported higher-level clades within modern birds. It is more parsimonious to assume that flamingos evolved from a highly aquatic ancestor than from a shorebird-like ancestor.” Do you see the fatal flaw here?

Figure x. From Mayr 2006, comparing the flamingo (above) to Palaelodus (middle) and the grebe (below) assuming a gradual transition of traits from grebe to flamingo.

Figure 5. From Mayr 2006, comparing the flamingo (above) to Palaelodus (middle) and the grebe (below) assuming a gradual transition of traits from grebe to flamingo that is not readily apparent because these taxa are not related to one another in the LRT.

Mayr employed 17 suprageneric taxa,
rather than generic taxa, even though his museum has a long list of bird skeletons in its collection. The Mayr 2004 cladogram is very poorly supported with most nodes failing to attain a Bootstrap score over 50. But it did nest Gavia with Phoenicopterus and grebes. Mayr also notes a parasite common to both grebes and flamingos alone among birds. Mayr did include tinamous in his analysis. So, I suppose character scoring is to blame here. Mayr’s hypothesis of relationships (Fig. 5) appears to be untenable. Many other taxa are closer to all three in morphology.

G. Mayr wrote via email upon seeing this cladogram:
“Hmm, to me the trees make little sense. If Palaelodus results within palaeognathous birds, many characters must be incorrectly scored. Furthermore, this exemplifies the pitfalls of laerge-scale cladistzic analyses.
Best wishes,
Gerald Mayr”

Unfortunately
this reply reflects the general view of PhDs. Large scale analyses, as readers know, test more possibilities, giving each taxon more opportunities to nest wherever they most parsimoniously fit.

References
Cracraft J 1981. Toward a phylogenetic classification of the recent birds of the world (Class Aves).Auk98: 681–714.
Mayr G 2004. Morphological evidence for sister group relationship between flamingos (Aves: Phoenicopteridae) and grebes (Podicipedidae). Zoological Journal of the Linnean Society. 140 (2): 157–169. doi:10.1111/j.1096-3642.2003.00094.x. ISSN 0024-4082.
Mayr G 2006. The contribution of fossils to the reconstruction of the higherlevelphylogeny of birds. Species, Phylogeny and Evolution 1 (2006):59–64.
Mayr G 2015. Cranial and vertebral morphology of the straight-billed Miocene phoenicopteriform bird Palaelodus and its evolutionary significance. Zoologischer Anzeiger – A Journal of Comparative Zoology. 254:18–26.
Milne-Edwards A 1863. Mémoire sur la distribution géologique des oiseaux fossiles et description de quelques espèces nouvelles. Annales des Sciences Naturelles (in French). 4 (20): 132–176.
Milne-Edwards, A 1867-1871. Recherches anatomiques et paleontologiques pour servir a l’histoire des oiseaux fos- siles de la France (Paris, G. Masson).
Olson SL, Feduccia A 1980a. Relationships and evolution of flamingos (Aves: Phoenicopteridae). Smithsonian Contributions to Zoology 316: 1–73.

wiki/Palaelodidae
wiki/Palaelodus
Dr. Gerald Mayr

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Molecules vs. morphology in bird phylogeny: Prum et al. 2015 part 2

Yesterday we looked at the basal bird taxa in both the LRT (morphology) and Prum 2015 (molecules/DNA). Today that continues with Prum’s Neoaves.

Prum et al. 2015 clade 3: Strisores
Derived from a sister to screamers and megapodes, the clade, Strisores, includes nightjars, potoos, and arising from owlet nightjars, the apodiformes (= swifts + hummingbirds). In other words, this clade includes several aerial insect-eaters with a wide, short, hooked rostrum and the hummingbirds, which have a narrow, long, not-hooked rostrum.

The skull and skeleton of Apus apus,

Figure 2. The skull and skeleton of Apus apus, the Common Swift. Note the big eyes, like an owl, and hooked beak, like an owl.

In the LRT
(subset Fig. 4) hummingbirds arise from similar taxa with a narrow and long rostrum, like the sea gull, Chroicocephalus. By contrast, swifts and their kin arise from the birds of prey clade all with a short, hooked rostrum. Swifts, like Apus (Fig. 2) are most closely related to owls. Perhaps that is why the owlet nightjars nest with them (they have not yet been tested). Googling: owlet nightjar reveals that the skull is very much like that of the tested swift, Apus with the same big eyes, like an owl, only in swifts they eyeballs are not so exposed.

The swift clade
includes such supreme masters of the air that the feet are reduced and seldom used except for perching. That they should arise from dirt-pecking, ground-dwelling chicken-like taxa that run around and rarely take flight, does not make sense when looking for a gradual accumulation of traits. The better relationship is with falcons (some of the fastest of all flyers) and owls (some of the quietest of all flyers), as recovered using morphology.

Prum et al. clade 4: Columbaves
this clade derived from a sister to the swifts, is divided between cuckoos and their kin (turacos and bustards) and pigeons and their kin. Among the bustards, the Kori bustard (Ardeotis lori) is the largest extant flying bird native to Africa.

Figure 2. Ardeotis skull. Note the ridge at the posterior cranium. Compare to figure 3, the heron skull is similar.

Figure 2. Ardeotis skull. Note the ridge at the posterior cranium. Compare to figure 3, the heron skull is similar.

By contrast, the LRT, based on morphology,
widely separates cuckoos and pigeons. Cukoos and the Kori bustard both nest with herons. Pigeons, like Columba, nest with wrens and dippers.

Figure 4. Subset of the LRT focusing on birds.

Figure 4. Subset of the LRT focusing on birds.

A reader asked about
Pandion, the osprey. Here it nests between falcons and owls + swifts.

References
Prum et al. (6 co-authors) 2015. A comprehensive phylogeny of birds (Aves) using targeted next-generation DNA sequencing. Nature 526:569–573. online

Molecules vs. morphology in bird phylogeny: Prum et al. 2015

As readers know
DNA cladograms do not match morphology cladograms, like the large reptile tree (LRT, 1124 taxa). Today we’ll be looking at some of the ‘strange bedfellows‘ that the Prum et al. 2015 DNA cladograms produced.

The LRT outgroups
include a long line of taxa extending through theropods and Jurassic birds, like Archaeopteryx), and other taxa going all the way back to Devonian tetrapods. That’s a solid out group. At every node the taxa document a gradual accumulation of traits. 76+ (the number may grow) Euornithine birds comprise the in group.

Figure 2. Basal Euornithes/horizontal. Click to enlarge.

Figure 1. Basal Euornithes. Click to enlarge this horizontal view of figure 1.

The Prum et al. cladogram employed 198 euornithine birds,
and nested the ones genetically closest to crocs at the base: Struthio, the ostrich + (Leipoa, the megapode + Chauna, the screamer).

Prum et al. chose two outgroup taxa:
Two crocodilians. No theropods were included. No Jurassic birds were included.

Crocs don’t have feathers.
Their forelimbs are not transformed into wings. Morphologically crocs are not good outgroups for euornithine birds, but, when using DNA, there are no better taxa living today. Unfortunately they do not provide a readily visible gradual accumulation of traits. For those we have pertinent taxa recovered by the LRT (Figs. 1, 2).

Figure 1. Basal euornithes to scale as recovered by the LRT.

Figure 2. Basal euornithes to scale as recovered by the LRT. Basal birds, for the most part, were long-legged forms. Short forms arrive easily by way of neotony as bird hatchlings have short legs. Yanornis is Early Cretaceous.

LRT Clades 1 and 2: Tinamous and Ratites
In the LRT the first clade includes an early Eocene tinamou-like bird, Pseudocrypturus + Apteryx, the kiwi. In the next clade mid-sized tinamous are basal to giant ratites – and all other extant birds.

Prum et al. Clade 1: Ratites and Tinamous
In the Prum et al. cladogram, the giant derived ostrich splits off first, then the smaller rhea, then the even smaller kiwi (Fig. 1), then the giant cassowary and giant emu. These last two are sisters to the clade of tinamous and all members of the Palaeognathae in the DNA study. In the Prum et al. tree, the ostrich is basal to all known ratites – and all other extant birds.

This may strike you as odd.
Generally basal taxa are average to small in size (Fig. 1) and without unusual traits, but the opposite is the case in the Prum et al. cladogram.

LRT Clade 3: Toothed Birds
The next clade in the LRT includes extinct toothed birds, a clade that, perforce, has to be ignored by the Prum et al. DNA study and, for that matter, has little bearing on extant bird evolution. This clade came and went without affecting the living birds. The presence of teeth are a secondary appearance, an atavism in this clade. The basalmost taxon, Changzuiornis, had tiny teeth and most closely resembled the long-snouted, long-legged outgroup tinamous. Later toothed birds had larger teeth, shorter legs and the most derived toothed bird, Hesperornis, had vestigial wings.

Teeth in birds,
whether true teeth with dentine and enamel, or false teeth made of bone or keratin also reappear most obviously in ducks, flamingoes and Pelagornis, the giant petrel. Less obviously tiny bill projections can be found in several other bird bills on close examination.

Prum et al. Clade 2: Neognathae + Galloanseriformes
In the Prum et al cladogram the first neognath clade includes megapodes and chickens on one branch and screamers and ducks in the other. In the LRT megapodes are indeed close to chickens, but ducks are far removed from screamers. Importantly, neither screamers nor megapodes are skeletally similar to the ostrich, their proximal outgroup in Prum et al.

LRT Clade 4: Birds of Prey
Generally tinamous are infrequent flyers and so are basal members of the next clade in the LRT, the long-legged, hooked beak predators, Cariama and Sagittarius. The latter gives rise to short-legged aerial predators like Pandion (ospreys),  Falco (falcons) + Targas (Old World vultures) and Tyto (owls) + Apus (swifts).

Figure 2. Which taxa share more traits? Phoenicopterus, the flamingo nests with Cariama, the seriema in the LRT, but with Gavia in the Prum et al. DNA study. Gavia nests with Thalasseus, the tern in the LRT.

Figure 3. Which taxa share more traits? Phoenicopterus, the flamingo nests with Cariama, the seriema in the LRT, but with Gavia in the Prum et al. DNA study. Gavia nests with Thalasseus, the tern in the LRT.

Phoenicopterus, the derived flamingo is a frequent flyer, but eats while standing with a strongly hooked beak and nests with the similarly gracile basal Cariama. In summary, and heretically, swifts and flamingos nest with birds of prey in the LRT. Prum et al. nest flamingos with short-limbed, straight-billed grebes, like Gavia, and all other shorebirds (Fig. 3). The LRT nests Gavia with short-limbed, straight-billed terns and only a few other shorebirds.

More later.
It’s a big subject.

References
Prum et al. (6 co-authors) 2015. A comprehensive phylogeny of birds (Aves) using targeted next-generation DNA sequencing. Nature 526:569–573. online

Laurin and Piñeiro 2017 ‘reassess’ mesosaurs

This paper came with much anticipation
following discussions several years ago with one of the authors (GHP) about mesosaurs (Fig. 2) and their relationship to pachypleurosaurs and thalattosaurs (Fig. 2) in the LRT. Unfortunately only 17 terminal taxa (many suprageneric) were employed by Laurin and Piñeiro 2017 (vs. the 1122 taxa in the large reptile tree, LRT).

Unfortunately,
pachypleurosaurs and thalattosaurs were not among the 17 taxa employed by Laurin and Piñeiro. That makes this study worthless with regard to mesosaur interrelations. Very unfortunate.

From the Laurin and Piñeiro methods:|
“We started from the matrix of Laurin and Reisz (1995), given that this was the matrix that we knew best, that we had confidence in the accuracy of the anatomical scoring, and that we were confident that we could apply the revised scores in a manner coherent with the original scoring.” 

Figure 2. Unfortunately pachypleurosaurs and thalattosaurs are omitted from this cladogram.

Figure 1. Unfortunately pachypleurosaurs and thalattosaurs are omitted from this cladogram from Laurin and Piñeiro 2017. I don’t know of any aquatic basal synapsids or basal captor hinds. Does anyone?

The authors
nested mesosaurs between Synapsida and Captorhinidae (Fig. 1). Neither suprageneric clade include basal members that in any way resemble mesosaurs.

A sampling of mesosaur sister taxa
as recovered by the LRT is shown here (Fig. 2). I challenge the authors to find better sister taxa among the Synapsida or the Captorhinidae.

Figure 2. Click to enlarge. The origin of ichthyosaurs and thalattosaurs from basal diapsids and basal mesosaurs. Relationships are rather apparent when seen in this context.

Figure 2. The origin of ichthyosaurs and thalattosaurs from basal diapsids and basal mesosaurs. Relationships are rather apparent when seen in this context. Chronology is a little mixed up based on earlier radiations and the rarity of fossil formation.

A gradual accumulation of traits
is what we’re all looking for in a cladogram. If you don’t find that using your inclusion set, expand your inclusion set until you do.

Professors Laurin and Reisz
are at the top of the list of professional paleontologists, and have been at the top for decades. Unfortunately they’re holding on to an invalid hypothesis. There is no monophyletic clade ‘Parareptilia.’ Included members don’t look alike and simple expansion of the dataset splits them to other parts of the reptile family tree.

If you find yourself working with top workers
in the field and the results don’t make sense, you may be obligated to follow their lead. That seems to happen all too often. You’ll make more sensible discoveries if you keep a modicum of independence, or complete independence. And you’ll avoid the professional embarrassment of being criticized online instead of being hailed and complimented for ‘finally putting it all together’. This was an opportunity lost, no matter how much detail and data was provided.

This paper was edited by
Holly Woodward (Oklahoma State University) and reviewed by Michael S. Lee (South Australian Museum) and Juliana Sterli (Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Argentina). It’s almost unheard of to see editors and reviewers listed near the titles of papers, btw. More often they are thanked in the Acknowledgements section.

On the plus side
I’m happy to see Piñeiro included a mesosaur skull with every bone colored (Fig. 3). That’s the way to do it nowadays. And if you’re into mesosaurs, this paper does provide a great deal of data about mesosaurs.

Figure 3. Mesosaur skull with bones colored by Laurin and Piñeiro 2017, modified from Piñeiro et al. 2012b.

Figure 3. Mesosaur skull with bones colored by Laurin and Piñeiro 2017, modified from Piñeiro et al. 2012.

References
Laurin M and Piñeiro GH 2017. A reassessment of the taxonomic position of mesosaurs, and a surprising phylogeny of early amniotes. Frontiers in Earth Science, 02 November 2017: 13 pp.  https://doi.org/10.3389/feart.2017.00088
Piñeiro G, Ferigolo J, Ramos A and Laurin M 2012. Cranial morphology of the Early Permian mesosaurid *Mesosaurus tenuidens* and the evolution of the lower temporal fenestration reassessed. Comptes Rendus Palevol. 11(5):379-391.

Earliest confuciusornithid is Wellnhoferia (Late Jurassic) contra Navalón et al. 2017

Navalón et al. 2017
report on “the earliest representative of the clade” Confuciusornithidae, a bird clade known from hundreds of Early Cretaceous specimens of the genus Confuciusornis (Fig. 1), first reported by Hou et al. 1995. Highlights (= summary) and partial abstract copied below, but the gist is: they found an early Cretaceous confuciusornithid earlier than than other confuciusornithids, but not early enough…

Unfortunately
the Navalón team did not expand their taxon list sufficiently. They should have looked at one of the Solnhofen birds, Wellnhoferia (Fig. 1). It is the earliest known representative of the clade Confuciusornithidae in the present study.

Figure 1. Confuciusornis (early Cretaceous) and Wellnhoferia (Late Jurassic), one of the Solnhofen birds traditionally considered Archaeopteryx.

Figure 1. Confuciusornis (early Cretaceous) and Wellnhoferia (Late Jurassic), one of the Solnhofen birds traditionally considered Archaeopteryx. These two nest together in the LRT apart from most other Solnhofen birds, including the type of Archaeopteryx.

Wellnhoferia (Late Jurassic, Fig. 1) is one of the Solnhofen birds traditionally considered Archaeopteryx (the Solnhofen specimen, or no. 6). It was initially misidentified as Compsognathus and kept in a private collection. Peter Wellnhofer re-identified the specimen as the 6th Archaeopteryx (Wellnhofer 1988a,b). Elzanowski (2001) thought the specimen was generically distinct from the type, so renamed it Wellnhoferia, to honor Wellnhofer.

Elzanowski 2001 reported
the 6th specimen differed from Archaeopteryx in having:

  1. a short tail (16-17 causals)
  2. a nearly symmetrical pattern of pedal rays (toes) 2–4 with metatarsals 2 and 4 of equal length and digit 4 substantially shorter than in Archaeopteryx with only 4 phalanges
  3. large size and details of the pelvic limb are different.

Prior workers overlooked
the circular hole in the proximal humerus, a trait shared with confuciusornids, but not scored in the large reptile tree (LRT, 1122 taxa). Confuciusornis and Welllnhoferia nest together in the LRT and apart from most other Solnhofen birds, including the type of Archaeopteryx. Zhongornis is the outgroup taxon for Confuciusornithids in the LRT.

Mayr et al. (including some guy other than me named D. Peters) 2007 described the tenth Solnhofen bird and did not recognize that Wellnhoferia was distinct from Archaeopteryx. Senter and Robins 2003 supported Elzanowski (2001).

FIgure 2. Wellnhoferia (Archaeopteryx #6) grandis pink highlighting the added tail vertebrae and the humerus with the hole in it, as in Confuciusornis.

FIgure 2. Wellnhoferia (Archaeopteryx #6) grandis pink highlighting the added tail vertebrae and the humerus with the hole in it, as in Confuciusornis.

 

Highlights from Navalón et al. 2017.
“We describe an adult specimen of a confuciusornithid bird from the Huajiying Formation of the Jehol Biota, which contains the earliest representatives of the clade. The new fossil is most similar to the synchronic but immature Eoconfuciusornis zhengi, supporting the validity of the latter taxon. The confuciusornithids from the early (Huajiying Formation) and late (Yixian Formation and Jiufotang Formation) Jehol Biota are morphologically distinct from each other.”

Abstract
“The Huajiying Formation contains the earliest deposits of the Jehol Biota, representing the world’s second oldest (after Solnhofen) avifauna. This avifauna includes the early confuciusornithid Eoconfuciusornis zhengi, the oldest occurrence of this clade and one of the earliest divergences of pygostylian birds. Although E. zhengi shows unique traits, the holotype’s immature age makes comparisons with the better known Confuciusornis sanctus problematic. As a result, the taxonomic validity of E. zhengi is controversial. We describe a small, osteologically adult confuciusornithid from the same deposits as E. zhengi. The new fossil is most similar to E. zhengi but also shares traits with the stratigraphically younger Confuciusornis. The humerus of the new fossil is straighter and more slender, and bears a less dorsally-developed deltopectoral crest compared with similarly-sized and smaller specimens of Confuciusornis. The morphology of the humerus is intermediate between E. zhengi and Confuciusornis and its proximal portion is pierced by a small deltopectoral foramen, absent in the holotype of E. zhengi. However, this foramen is much smaller than in any other confuciusornithid.”

The takeaway
from this blogpost repeats an earlier hypothesis: The initial radiation of birds preceded the Late Jurassic. Solnhofen birds, few of which are congeneric, represent that a wide gamut of taxa, each a representative from that earlier initial radiation.

On a side note
Madagascar separated from Africa 160 million years ago, ten million years prior to the Solnhofen formation and the Solnhofen birds that are found there. On the African side of the split were the ancestors of the ostrich, Struthio. On the Madagascar side were the ancestors of the elephant bird, Aepyornis.

References
Elzanowski A. 2001. A new genus and species for the largest specimen of Archaeopteryx. Acta Palaeontologica Polonica 46(4):519–532.
Hou L, Zhou Z, Gu Y and Zhang H 1995. Confuciusornis sanctus, a new Late Jurassic sauriurine bird from China. Chinese Science Bulletin 40: 1545–1551.
Mayr G, Pohl B, Hartman S and Peters DS 2007. The tenth skeletal specimen of Archaeopteryx. Zoological Journal of the Linnean Society. 149 (1): 97–116.
Navalón G, Meng Q-G, Marugán-Lobón J, Zhang Y, Wang B-P,  Xing H, Liu D and Chiappe LM 2017. Diversity and evolution of the Confuciusornithidae: Evidence from a new 131-million-year-old specimen from the Huajiying Formation in NE China. Journal of Asian Earth Sciences (advance online publication)
doi: https://doi.org/10.1016/j.jseaes.2017.11.005
http://www.sciencedirect.com/science/article/pii/S1367912017306223
Senter P and Robins JH 2003. Taxonomic status of the specimens of Archaeopteryx. Journal of Vertebrate Paleontology 23(4):961–965.
Wellnhofer P 1988. A New Specimen of Archaeopteryx. Science 240(4860):1790–1790.

wiki/Confuciusornis
wiki/Wellnhoferia

Old data (from 1896) nests the elephant bird, Aepyornis, with the ostrich, Struthio

Longtime readers know
I like to make repairs and get things right, whether working from published papers or my own images and data. And longtime readers know I don’t always get things right the first time, usually for good reason (see below). I’ve been looking for Andrews 1896 for several weeks and finally got it. All the earlier problems could have been avoided if I had the data earlier that I have now. Alas, that’s just how it goes…

Figure 1. Aepyornis maximus along with eggs, the largest known. The new skull replaces the original one.

Figure 1. Aepyornis maximus along with eggs, the largest known. The new skull replaces the original one.

Earlier data on the skull of the elephant bird,
Aepyorniscame from a photograph of a commercially available restored cast. Unfortunately, the restoration included a little too much imagination and did not match the only other data currently (and most recently) available (Fig. 2, Andrews 1896).

The data from the embryo in the giant egg attributed to Aepyornis,
did not contribute to the current matrix scoring. That would be akin to creating a chimaera. However, after the fact, it’s noteworthy that the embryo still has ostrich traits not found in the present adult skull data for Aepyornis. The fragile palatal and cheek regions were not preserved or collected in the adult. The fragile cheek regions were not yet developed (or lost in the debris) of the embryo.

Figure 4. NatGeo embryo compared to Struthio and adult Aepyornis. The original maxilla is reinterpreted as the palatine. The original premaxilla is a fused premaxilla + maxilla. The original Nat Geo skull was put together in computer software from scattered parts. Mesethmoid inverted in revision. Aepyornis does not have bulbous squamosals found in Struthio and the NatGeo embryo. Not to scale.

Figure 2. NatGeo embryo compared to Struthio and adult Aepyornis. The original maxilla is reinterpreted as the palatine. The original premaxilla is a fused premaxilla + maxilla. The original Nat Geo skull was put together in computer software from scattered parts. Mesethmoid inverted in revision. Aepyornis does not have bulbous squamosals found in Struthio and the NatGeo embryo. Not to scale. The mystery of the embryo is coming into clearer focus with the latest elephant bird skull data and taxonomy.

All earlier posts
and ReptileEvolution.com pages regarding Aepyornis have been repaired. Good science makes repairs all the time. Better data is always welcome. Every hypothesis remains hypothetical, until it is confirmed over and over again through testing.

Using commercially available skulls for data
is still a good idea, but it’s also a good idea to see which parts are real and which are restored with clay. I don’t know if several skull parts from several specimens of Aepyornis were all put together to produce the skulls currently found in museums and skull shops. Andrews 1896 reports the material he published came from two. Better to take data from one specimen than to make a chimaera of several specimens, because problems like this tend to happen. Sometimes you take what you can get.

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

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

This should make certain readers happy
that Aepyornis returns to the ratites. I’m happy that better data has come forth. The latest DNA tests prefer Aepyornis to nest with the kiwi. Morphology leans toward the ostrich. With the new nesting of the elephant bird Casuarius, the cassowary, nests between tinamous and ostriches + elephant birds.

References
Andrews CW 1896. On the skull, sternum, and shoulder-girdle of Aepyornis. Ibis, Seventh Series, 2:376-389.
Balanoff AM 2003. Osteological description of an embryonic elephant bird (Ratitae: Aepyornis) using high-resolution X-ray computed tomography, with a discussion of growth in Aepyornis. M.S. thesis, The University of Texas, Austin, Texas, 175 pp.
Balanoff AM and Rowe T 2007. Osteological description of an embryonic skeleton of the extinct elephant bird, Aepyornis (Palaeognathae: Ratitae). Journal of Vertebrate Paleontology 27(sp9):1–53.
Geoffroy Saint-Hilaire I 1851. [Note sur les onze espèces nouvelles do Trochilidés de M. Bourcier.] Compt. Rend. de l’Acad. Sci 32:188.
Linnaeus C 1758. Systema naturæ per regna tria naturæ, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Tomus I. Editio decima, reformata.
Temminck 1815. Histoire naturelle generale des pigeons et des gallinaces.
Accompagne de planches anatomiques. 3: 552–747

wiki/Rhynchotus
wiki/Cassowary
wiki/Ostrich
wiki/Aepyornis

The origin of giant ‘birds’: Tyrannosaurus, a giant Zhenyuanlong

Today we conclude our foray into giant birds with a non-bird.
I could not resist this one. Today’s taxa are not birds, but very convergent. Hope you like it as we revisit the very bird-like Zhenyuanlong, with its long wing feathers, and its giant descendant, Tyrannosaurus rex (Fig. 1). We looked at this heretical pair revealed by phylogenetic analysis for the first time in the large reptile tree earlier here.

Figure 1. Zhenyuanlong compared to scale with the foot of T-rex and a another overall view of T-rex to a similar overall length.

Figure 1. Zhenyuanlong compared to scale with the foot of T-rex and a another overall view of T-rex to a similar overall length.

Tyrannosaurus rex (Osborn 1905) Late Cretaceous, 65 mya, 12.3 m in length, was derived from a sister to Sinocalliopteryx and was a sister to bird-like dinosaurs in the large reptile tree. Several varieties are known. Some are more robust. Others are gracile and smaller.

Zhenyuanlong suni (Lü and Brusatte 2015, JPM-0008) Early Cretaceous, 122 mya, over 1m in length, was derived from a sister to Tianyuraptorand is an ancestral sister to Tyrannosaurus. The fossil preserves wing feathers and so was considered the largest of the Chinese winged dromaeosaurs. Click here to see the list of traits shared with tyrannosaurs not with dromaeosaurs and to learn more. Note the short torso and tall, narrow orbit. This fossil shows that tyrannosaurs once had flight feathers.

We also looked at
the tiny arms of T-rex earlier here. They were tiny wings.

References
Lü J and Brusatte SL 2015. A large, short-armed, winged dromaeosaurid (Dinosauria: Theropoda) from the Early Cretaceous of China and its implications for feather evolution. Scientific Reports 5, 11775; doi: 10.1038/srep11775.
Osborn HF 1905. Tyrannosaurus and other Cretaceous carnivorous dinosaurs. Bulletin of the AMNH (New York City: American Museum of Natural History) 21 (14): 259–265.

wiki/Tyrannosaurus
wiki/Zhenyuanlong