Dodos are flightless vultures, not pigeons.

This is what happens
when you add taxa to the mix. The large reptile tree (LRT, 1105 taxa) does what it does without tradition, taxon exclusion, bias or tribute to any overlord professor. Dodos and solitaires (Figs. 1, 3, 5-7) are not pigeons (Fig. 2) in the LRT (Fig. 8).  Given the present list of taxa dodos nest as flightless vultures, a relationship proposed over a hundred years ago by Owen (1846), but abandoned within two years by Strickland and Mehlville (1848) in favor of the earlier pigeon hypothesis by Reinhart (1842). And that has been gospel ever since.

Figure 1. The dodo, Raphus, compared to the New World vulture, Coragyps. These two nest together apart from the pigeons in figure 1. 

Figure 1. The dodo, Raphus, compared to the New World vulture, Coragyps. These two nest together apart from the pigeons in figure 1.

Current thinking (going back to Reinhart 1842)
(Wikipedia dodo page) nests the dodo (genus: Raphus, Fig. 1) with the nicobar pigeon (genus: Caloenas, Fig. 2). If you’ve ever wondered about this, I had the same giant question mark over my head, too. Here, finally, the dodo gets tested in a large gamut taxon list and another long-standing paradigm falls by the wayside.

Figure 1. Two pigeon skulls, Caloenas and Columba. These taxa nest together apart from vultures and the dodo, Raphus.

Figure 2. Two pigeon skulls, Caloenas and Columba. These taxa nest together apart from vultures (Fig. 8) and the dodo, Raphus (figure 2). Even the palate is different here. By convergence, and beside the point, these pigeons look more like the vulture, Coragyps, and less like the dodo, Raphus (Fig. 1).

The LRT 
nests the dodo, Raphus, with the New World vulture, Coragyps (Fig. 1). So, the dodo is a flightless vulture, not a pigeon. Both are derived from soaring seabirds like Macronectes. This addition of related taxa pushes the puffin, Fratercula, and the auk, Pinguinus, off to the side, as sisters to the Coragyps/Raphus clade. They also had a common ancestor among long-ranging sea birds,

Figure 4. Dodo (Raphus) skeletal data.

Figure 3. Dodo (Raphus) skeletal data.

According to Wikipedia:
“The dodo was variously declared a small ostrich, a rail, an albatross, or a vulture, by early scientists. In 1842, Danish zoologist Johannes Theodor Reinhardt proposed that dodos were ground pigeons, based on studies of a dodo skull he had discovered in the collection of the Natural History Museum of Denmark. This view was met with ridicule, but was later supported by English naturalists Hugh Edwin Strickland and Alexander Gordon Melville in their 1848 monograph The Dodo and Its Kindred, which attempted to separate myth from reality. After dissecting the preserved head and foot of the specimen at the Oxford University Museum and comparing it with the few remains then available of the extinct Rodrigues solitaire (Pezophaps solitaria) they concluded that the two were closely related. Strickland stated that although not identical, these birds shared many distinguishing features of the leg bones, otherwise known only in pigeons.”

“Strickland and Melville pointed to the very short keratinous portion of the beak, with its long, slender, naked basal part.”

A trait shared with Coragyps by convergence.

Figure 3. When vultures drift north and start finding fish attractive they evolve into auks and puffins.

Figure 4. When vultures drift north and start finding fish attractive they evolve into auks and puffins.

“Other pigeons also have bare skin around their eyes, almost reaching their beak, as in dodos.”

As in Coragyps.

Figure 4. Raphus skull compared to Coragyps, a vulture, and Caloenas, a pigeon. White arrow points to nostril.

Figure 5. Raphus skull compared to Coragyps, a vulture, and Caloenas, a pigeon. White arrow points to nostril.

“The forehead was high in relation to the beak, and the nostril was located low on the middle of the beak and surrounded by skin, a combination of features shared only with pigeons.”

And vultures.

“The legs of the dodo were generally more similar to those of terrestrial pigeons than of other birds, both in their scales and in their skeletal features.”

I can’t comment on this with available data, other than to say the description is too general and many bird legs are similar in structure, inside and out.

“Depictions of the large crop hinted at a relationship with pigeons, in which this feature is more developed than in other birds.”

Also found in vultures.

“Pigeons generally have very small clutches, and the dodo is said to have laid a single egg.”

Coragyps lays from one to three eggs.

“Like pigeons, the dodo lacked the vomer and septum of the nostrils, and it shared details in the mandible, the zygomatic bone, the palate, and the hallux.”

You can see through both nares in Coragyps, too.  The rest of this description is too generalized to comment on, other than to say the LRT recovers more dodo traits shared with the vulture, Coragyps than with the pigeon, Colaenas.

“The dodo differed from other pigeons mainly in the small size of the wings and the large size of the beak in proportion to the rest of the cranium.”

Same with Coragyps.

Not too many skeletal traits
listed by these authors. The LRT employs only skeletal traits. Not sure why vultures were excluded from dodo cladograms. And if they were not excluded, one has to wonder why dodos did not nest with Old World vultures. The long list of synapomorphies easily overwhelms any list of pigeon traits.

Raphus cucullatus (Linnaeus 1758; recently extinct; 1m tall) is the flightless dodo, endemic to the island of Maritius, east of Madagascar. Traditionally the closest living relative is the Nicobar pigeon, Caloenas. Here Raphus nests with Pezohaps and Coragyps, a New World vuluture.

The dodo has a less famous flightless relative
more closely related to it than to Coragyps. Meet Pezophaps solitaire (Fig. 6), the flightless solitaire, from the island of Rodrigues, east of Madagascar. It was also recently discovered and recently decimated by humans.

Figure 5. Swan-sized, Pezophaps, the solitaire, is the closest dodo relative. It is likewise closer to New World vultures than to African pigeons.

Figure 6. Swan-sized, Pezophaps, the solitaire, is the closest dodo relative. It is likewise closer to New World vultures than to African pigeons.

Pezophaps solitaria (Gmelin 1789; recently extinct; 70cm tall) is the flightless solitaire, from the island of Rodrigues, east of Madagascar. Here it nests with the dodo, Raphus, and both are related to the New World vulture, Coragyps.

Figure 6. Pezophaps skull. This is a very robust skull for any bird or any theropod dinosaur. 

Figure 7. Pezophaps skull. This is a very robust skull for any bird or any theropod dinosaur.

Coragyps atratus (LaMout 1853; 56 cm in length, 1.5m wingspread) is the extant black vulture and a sister to the giant petrel. Note the similar premaxilla. As in Raphus, the dodo, the head and neck lack feathers.

Unlike the flightless ratites
these flightless birds kept a deep sternum, despite having tiny wings.

Figure 8. Subset of the LRT focusing on birds. Here Raphus, the dodo, nests with the New World vulture, Coragyps (in orange), not the pigeon, Caloenas (in green).

Figure 8. Subset of the LRT focusing on birds. Here Raphus, the dodo, nests with the New World vulture, Coragyps (in orange), not the pigeon, Caloenas (in green).

Oddly, if you’ve noticed…
dodos and solitaires both lived east of Madagascar, in the Old World. They are not closely related to Old World vultures like, Torgos. Rather, dodos and solitaires are related to New World vultures. How can that be? All hypotheses and speculations are welcome. IMHO we’re going to find a long-ranging, soaring seabird that was the last common ancestor of both dodos and New World vultures. Or we’ll find some New World vulture fossils in the Old World, out-competed or diseased out of existence, except on those tiny islands East of Madagascar.

Size matters, sometimes.
Both the dodo and the solitaire are closer in size to soaring sea birds and vultures than to pigeons. I think the historical confusion arose because, for reasons unknown, pigeons do indeed share several traits with New World vultures (including dodos) by convergence (Figs. 1, 2).

At this point, I look for further citations
Meuer et al. 2014 report in an abstract that only one complete dodo skeleton is known from a single individual. Others are chimeric combinations of incomplete specimens. They report, “Dodo cranial morphology is characterized by a lengthening and heightening of the maxilla, a concomitant antero-posterior compression of the cranium and a dorsally expanded frontal region. There is no ossified nasal septum, and both specimens lack an ossified vomer. Although the orbital region forms a large part of the cranium, it is reduced in size relative to extant Columbiformes. The occipital region is flat, wide and oriented vertically. The foramen magnum and the occipital condyle are located in a posterior position on the skull. This arrangement is similar to that of the closely related Solitaire of Rodriguez, Pezophaps solitaria, but differs from extant Columbiformes, including the dodo’s closest living relative, the Nicobar Pigeon (Caloenas nicobarica).

See how hey bought into the tradition without testing. Now look at all the differences these authors find between pigeons (columbids) and the dodo:

“In these columbids, the occipital region is more rounded and both the foramen magnum and occipital condyle are located ventrally. The fossa temporal is of the dodo is deep and narrow, and the quadratum is X-shaped. Both the mandible and cranium are only gently curved dorso-ventrally. The mandibular rami are high and narrow, and contain only a single mandibular foramen. The medial mandibular process is large and triangular, and together with articulatory processes on the basitemporal plate, argues for a secondary articulation of the mandible with the basitemporal plate. Our study of the Thirioux specimens highlights the dodo’s peculiar cranial morphology, which likely evolved in response to a more demanding and specialized lifestyle and feeding mechanism than previously appreciated.”

Shapiro et al. 2002 report, “The evolutionary history of the dodo is very poorly understood.” They phylogenetically tested the dodo only against Pezophaps and 35 pigeons and doves… and they used DNA.

Switek 2011 reports, “First-hand accounts of the birds agreed that they sported plumage that was black to grey in color,”

Hume 2006 reports, “More has been written about the dodo Raphus cucullatus of Mauritius than any other bird. Many conclusions based on the available data are problematic.”

Strckland and Mehlville 1848, credit Owen 1846 with relating the dodo to the raptorial birds and Reinhart 1842 for noting the pigeon affinities with the tubular naris (Fig. 5).

Naish 2014 reviewed a book by Parish 2012. “Today it’s well known and near-universally accepted that dodos and solitaires are pigeons, deeply nested within Columbidae. Historically, however, these birds have been considered related to, or members of, ratites, gamebirds, swans, penguins, vultures, waders, and rails. Parish reviews all of these, often fanciful, suggestions (and others), using the assorted family trees and other diagrams produced by the respective authors.”

I did not have access to this book prior to posting this blog. But I have seen the evidence and I understand and attempted to show that dodos and solitaires nest with New World vultures rather than pigeons in the LRT. As readers know, I am not adverse to testing long-held paradigms and purported clades. This is just one more heresy that will someday be embraced or invalidated by others who run similar tests.

References
Gmelin JF 1789. Caroli a Linné … Systema Naturae per Regna Tria Naturae, Secundum Classes, Ordines, Genera, Species, Cum Characteribus, Differentiis, Synonymis, Locis. Editio Decima Tertia, Aucta, Reformata/ cura Jo. Frid. Gmelin. Volume 1, part 3. Lipsiae: Impensis Georg. Emanuel. Beer.
Hume J 2006. The history of the Dodo Raphus cucullatus and the penguin of Mauritius Historical Biology, 18 (2), 65-89 DOI: 10.1080/08912960600639400
Hume JP, Cheke AS and McOran-Campbell A 2009. How Owen ‘stole’ the Dodo: academic revelry and disputed rights to a newly discovered sub fossil in nineteenth century Mauritius. Historical Biology 21:33–49. online pdf
LeMaout JEM 1853. Les trois regnes de la nature. Regne animal. Histoire naturalle des oiseaux, suivant la classification de M. Isidore Geoffroy-Saint-Hillaire, avec l’indication de leurs moeurs et de leurs rapports avec les arts, le commerce et l’agriculture. Par Emm. Le Maout. L. Curmer. Paris 425 pp.
Linnaeus C 1758. Systema naturæ per regna tria naturæ, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Tomus I. Editio decima, reformata.
Meijer H, Claessens L, Hume J, Jando A and Rijsdijk K 2014. A re-evaluation of cranial anatomy of the dodo (Raphus cucullatus) based on two previously undescribed specimens. Journal of Vertebrate Paleontology abstracts, 2014:186.
Naish D 2014. A review of ‘The Dodo and the Solitaire: A natural history’. Journal of Vertebrate Paleontology 34(2):489-490.
Owen R 1846. Observations on the Dodo. Proceedings of the Zoollogical Society of London 1846:51–53.
Parish JC 2012. The dodo and the solitaire: a natural history. Indiana University Press, Bloomington, IN 406 pp.
Reinhardt JT 1842. In: Kroyer H, editor. Noiere Oplysning om det I Kiobenhavn fundne Drontehoved. Vol. 4. København (Denmark): Naturhistorisk Tidskrift. p. 71.
Shapiro B et al. (7 co-authors) 2002. Flight of the Dodo. Science Brevia. 295:5560:1683.
Strickland HE and Melville AG 1848. The dodo and its kindred. London: Reeve, Benham & Reeve. p 141.
Switek B 2011. The dodo is dead, long live the dodo! Wired.com

wiki/Coragyps atratus
wiki/Dodo
wiki/Rodrigues_solitaire

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A fresh reconstruction of Pelagornis nests it with Macronectes

Updated October 12, 2017 with a longer maxilla and a shorter mandible and a new nesting. 

Pelagornis chilensis (Lartet 1857, Mayr and Rubilar-Rogers 2010; Miocene; MNHN SGO.PV 1061; Fig. 1) is an extinct giant soaring bird here related to Macronectes, the giant Southern petrel (Fig. 2). Bony, not true teeth, developed along the jaw margins. The external naris was divided by bone.

Mayr and Rubilar-Rogers reported,
“We finally note that the phylogenetic affinities of bony-toothed birds still have not been convincingly resolved.” I made a fresh reconstruction (Fig. 1) and tested it against a long list of Cretaceous and post-Cretaceous birds to see where it nests.

FIgure 1. Pelagornis, new reconstruction of skull along with overall reconstruction from Mayr and Rubilar-Rogers

FIgure 1. Pelagornis, new reconstruction of skull along with overall reconstruction from Mayr and Rubilar-Rogers

Pelagornis is an earlier larger version of
the large soaring sea birds, the petrels (Figs. 2, 3), not far from New World vultures.

Figure 5. Macronectes, the Southern giant petrel, in vivo.

Figure 2. Macronectes, the Southern giant petrel, in vivo.

Figure 3. Macronectes giganteus, the extant Southern giant petrel.

Figure 3. Macronectes giganteus, the extant Southern giant petrel. Note the long maxilla. 

My earlier error was realized
when birds with long maxillae, like Macronectes, starting appearing in the LRT.

References
Lartet E 1857. Note sur un hum´erus fossile d’oiseau, attribu ´e `a un tr `es-grand palmip`ede de la section des Longipennes. Comptes rendus hebdomadaires des S´eances de l’Acad´emie des Sciences (Paris) 44:736–741.
Mayr G and Rubilar-Rogers D 2010. Osteology of a new giant bony-toothed bird from the Miocene of Chile, with a revision of the taxonomy of Neogene Pelagornithidae. Journal of Vertebrate Paleontology 30(5):1313-1340.

wiki/Pelagornis

Roof and floor, no walls: the skull of Aepyornis

Figure 1. The skull of Aepyornis is lacking lateral bones that help delineate fenestra, all of which are confluent.

Figure 1. The skull of Aepyornis is lacking lateral bones that help delineate fenestra, all of which are confluent.

Figure 2. Aepyornis maximus was the heaviest of all birds. Once considered a ratite, Aepyornis nests in the LRT with ducks, like Ana (Fig. 3).

Figure 2. Aepyornis maximus was the heaviest of all birds. Once considered a ratite, Aepyornis nests in the LRT with ducks, like Ana (Fig. 3).

Sure it looks like a giant ostrich,
but Aepyornis nests closer to geese and ducks. And let’s not forget that the basal duck, Presbyornis (Fig. 4), also had long, stork-like legs.

Aepyornis maximus (Geoffroy Saint-Hilaire) is the recently extinct elephant bird restricted to Madagascar. It is the heaviest of all birds and 3m tall. Long considered a ratite related to Struthio and especially Apteryx, here this taxon is recovered as a giant flightless goose. Note: all the fenestrae are confluent.

Figure 3. Anas, the mallard duck, shares more trait with Aepyornis than with other taxa in the LRT.

Figure 3. Anas, the mallard duck, shares more trait with Aepyornis than with other taxa in the LRT.

Anas platyrhynchos (Linneaus 1758) is the extant mallard duck. It has shorter legs than Presbyornis. This toothless bird has toothlike serrations on the keratin that covers its broad bill.

Figure 4. Presbyornis is the prehistoric long-legged duck, close to the elephant bird, Aepyornis.

Figure 4. Presbyornis is the prehistoric long-legged duck, close to the elephant bird, Aepyornis.

Presbyornis pervetus (Wetmore 1926; Olson and Feduccia 1980; earliest Eocene, 62 mya) is one of the first of the clade Anseriformes (ducks, geese and kin). It is known from scattered bones and was originally considered a flamingo relative, due to its long legs. The duck-like skull was found later. This clade is the sister to the predatorial long-legged taxa, like Cariama and Sagittarius.

References
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.
Olson SL and Feduccia A 1980. Presbyornis and the origin of the Anseriformes (Aves: Charadriomorphae). Smithsonian Contributions to Zoology 323: 1–24.
Wetmore A 1926. Fossil birds from the Green River deposits of Eastern Utah. Annals of the Carnegie Museum 16: 391-402.

wiki/Anas
wiki/Presbyornis
wiki/Aepyornis

SVP abstracts 2017 – Notoungulata reexamined

Remember when
members of the clade Notoungulata were dismantled and shipped to various other clades within Theria in the large reptile tree (LRT, 1051 taxa)? Keep that in mind as you read this abstract by West 2017.

From the West 2017 abstract:
“Notoungulata is an extremely diverse and disparate, entirely extinct order of placental
mammals, largely endemic to South America, which persisted through Cenozoic. There
are disagreements on intraordinal relationships among notoungulates, but the roots of the
order within Placentalia are even more enigmatic. A critical challenge is the lack of DNA
(though one taxon now has yielded collagen protein sequences), thus the greater impact
of the interpretation of morphological homology across superorders, particularly for
herbivorous ungulate placentals. This is because most characters used in higher-level
analyses of Placentalia do not adequately capture the nuances of unguligrady,
cursoriality, lophodonty, and hypsodonty, hindering accurate phylogenetic
reconstructions.

“A long-held, recently reinforced, morphology-based hypothesis for Notoungulata is that
they are most closely related to Tethytheria, an afrothere group including elephants and
manatees. An alternative hypothesis, recently corroborated by ancient collagen sequence
data, is that notoungulates and litopterns (another extinct South American ungulate order)
are sister to Perissodactyla. To test these starkly different alternatives, as well as the
hypothesis implicit in both that Notoungulata is monophyletic, I built on a published
large total-evidence matrix that was built to test placental interordinal relationships. I
added seven notoungulate and one litoptern species, a 10% taxon sampling increase. I
expanded character sampling, adding two morphological characters often used in
notoungulate intraordinal systematics, one dental and one cranial, and I added the
recently published collagen loci that had linked notoungulates and litopterns to
Perissodactyla. In multiple analyses of the total-evidence dataset and its partitions, my
results show that notoungulates form a clade sister to Tethytheria, supporting the
morphological hypothesis and overturning the hypothesis based only on the collagen
data. Intriguingly, nested consistently within the notoungulate clade in my results is an
extant taxon that also has oscillated from Perissodactyl to Afrothere: hyraxes. Molecular
data put hyraxes in Paenungulata (Afrotheria); I found new morphological character
support for this, and for the placement of Notoungulata.

“In testing affinities of fossil taxa, morphology retains critical importance even in light of
ancient molecular data. My results also reinforce the value of well-constructed homology
statements and thorough taxon sampling.”

Note that West 2017

  1. Bemoans the lack of DNA for this purported clade, not realizing that DNA analyses do not bring insight to morphological studies, but constantly confuse topologies.
  2. Discusses characters like cursoriality, but those have no business in analysis.
  3. Tests the concept of a monophyletic Notoungulata. Thats’ good! Recovers a monophyletic notoungulata. That’s probably due to taxon exclusion. Many former notoungulates now nest with marsupial wombats.
  4. Recovered hyraxes with purported notoungulates, not with elephants and manatees. This is a red flag showing some sort of error in the data set.
  5. Does not list the genera sampled.
  6. Recovers Afrotheria. That’s probably due to the DNA in the dataset.

West should
remove DNA characters, add many more fossil taxa (including wombats) and report findings afterwards. That we’d all like to see.

West AR 2017. Resolving the affinities of Notoungulata; Character selection, taxon sampling,and the influence of ancient molecular data. SVP abstracts 2017.

Shringasaurus: new rhynchocephalian lepidosaur with horns

Sengupta, Ezcurra and Bandyopadhyay 2017 bring us
a new, very large, horned rhynchocephalian lepidosaur, Shringasaurus (Fig. 1). Unfortunately, that’s not how the Sengupta team nested it (due to the sin of taxon exclusion, see below). Even so, there is consensus that the new taxon is closely related to the much smaller Azendohsaurus (Fig. 1).

Figure 1. Shringasaurus to scale with Azendohsaurus. Line art modified from Sengupta et al. Color added here. Note the anterior lappet of the maxilla over the premaxilla. The supratemporal  (dark green) remains.

Figure 1. Shringasaurus to scale with Azendohsaurus. Line art modified from Sengupta et al. Color added here. Note the anterior lappet of the maxilla over the premaxilla. The supratemporal  (dark green) remains.

From the abstract:
“The early evolution of archosauromorphs (bird- and crocodile-line archosaurs and stem-archosaurs) represents an important case of adaptive radiation that occurred in the aftermath of the Permo-Triassic mass extinction. Here we enrich the early archosauromorph record with the description of a moderately large (3–4 m in total length), herbivorous new allokotosaurian, Shringasaurus indicus, from the early Middle Triassic of India. The most striking feature of Shringasaurus indicus is the presence of a pair of large supraorbital horns that resemble those of some ceratopsid dinosaurs. The presence of horns in the new species is dimorphic and, as occurs in horned extant bovid mammals, these structures were probably sexually selected and used as weapons in intraspecific combats. The relatively large size and unusual anatomy of Shringasaurus indicus broadens the morphological diversity of Early–Middle Triassic tetrapods and complements the understanding of the evolutionary mechanisms involved in the early archosauromorph diversification.”

Allokotosauria
Shringasaurus was nested in the clade, Allokotosauria, According to Wikipedia, “Nesbitt et al. (2015) defined the group as a  containing Azendohsaurus madagaskarensis and Trilophosaurus buettneri and all taxa more closely related to them than to Tanystropheus longobardicus, Proterosuchus fergusi, Protorosaurus speneri or Rhynchosaurus articeps.” This definition was based on the invalidated hypothesis that rhynchosaurs and allokotosaurs were close to the base of the Archosauriformes as the addition of more taxa will demonstrate. Basically this clade equals Trilophosaurus, Azendohsaurus and now Shringasaurus. In the large reptile tree (LRT, 1049 taxa) this clade nests between Sapheosaurus + Notesuchus and Mesosuchus + Rhynchosauria all nesting within Sphenodontia (=  Rhynchocephalia), so they are all lepidosaurs. All you have to do is add pertinent taxa to make this happen in your own phylogenetic analysis.

Figure 2. Scene from the 1960 film, The Lost World, featuring a giant iguana with horns added presaging the appearance of Shringasaurus.

Figure 2. Scene from the 1960 film, The Lost World, featuring a giant iguana with horns added presaging the appearance of Shringasaurus.

Coincidentally the 1960 film,
The Lost World featured an iguana made up with horns similar to those of Shringasaurus.

References
Sengupta S, Ezcurra MD and Bandyopadhyay S 2017. A new horned and long-necked herbivorous stem-archosaur from the Middle Triassic of India. Nature, Scientific Reports 7: 8366 | DOI:10.1038/s41598-017-08658-8 online here.

No Wiki page yet.

You heard it here first: Chilesaurus is a basal ornithischian confirmed.

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

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

Figure 2. Look familiar? Here are the pelves of Jeholosaurus and Chilesaurus compared. As discussed earlier, this is how the ornithischian pelvis evolved from that of Eoraptor and basal saurorpodomorpha.

Figure 2. Look familiar? Here are the pelves of Jeholosaurus and Chilesaurus compared. As discussed earlier, this is how the ornithischian pelvis evolved from that of Eoraptor and basal saurorpodomorpha.

A new paper by Baron and Barrett 2017 confirms Chilesaurus (Fig. 1) as a basal member of the Ornithischia, not a bizarre theropod. As long time readers know, this was put online two years ago (other links below) in this blog.

Unfortunately, the authors don’t have an understanding of the interrelationships of phytodinosaurs, even though they report, For example, Chilesauruspossesses features that appear ‘classically’ theropod-like, sauropodomorph-like and ornithischian-like…” Nor did they mention the sister taxon, Jeholosaurus (Fig. 2).

Remember,
discovery only happens once.
More on this topic later.

This note went out this morning:
Thank you, Matthew,
for the confirmation on Chilesaurus.
In this case, it would have been appropriate to include me as a co-author since I put this online two years ago.

https://pterosaurheresies.wordpress.com/2015/04/28/chilesaurus-new-dinosaur-not-so-enigmatic-after-all/
http://www.reptileevolution.com/reptile-tree.htm
http://www.reptileevolution.com/chilesaurus.htm

References
Baron MG, Barrett PM 2017. A dinosaur missing-link? Chilesaurus and the early evolution of ornithischian dinosaurs. Biol. Lett. 13: 20170220. http://dx.doi.org/10.1098/rsbl.2017.0220 pdf online

Best regards,

What is Fruitafossor? A xenarthran close to Peltephilus.

This appears to be
yet another case of pertinent taxon exclusion. Today’s fossorial digger has several universally acknowledged xenarthran (edentate) traits. For reasons unknown it was not tested against another fossorial xenarthran, Peltephilus. Rather the authors compared their digger to an arboreal sloth, Bradypus, among several other taxa, including distinctly different anteaters and armadillos.

Figure 1. Scapula of Fruitafossor compared to several candidate sisters. Luo and Wible made things a bit more difficult by presenting left and right scapulae. Here they are all left scapulae for ready comparison. There is no doubt that the Fruitafossor scapula looks more like that of Ornithorhynchus.

ºªº Figure 1. Scapula of Fruitafossor compared to several candidate sisters. Luo and Wible made things a bit more difficult by presenting left and right scapulae. In frame 2 they are all left scapulae for ready comparison. There is no doubt that the Fruitafossor scapula was illustrated to look more like that of Ornithorhynchus. Unfortunately the photo data (Fig. 2) does not clearly support that shape. That shape is so important, it needed to be better documented.

Luo and Wible 2005
brought us a small, mostly articulated, rather crushed and incomplete Late Jurassic mammal with simple blunt teeth and digging forelimbs. Fruitafossor windscheffeli (Figs. 1–6) is best represented by a CT scan (Figs. 2–4) and original drawings (Figs. 5, 6) created by the Luo and Wible team.

Figure 2. Fruitafossor in situ from Digimorph.org and used with permission and here colorized to an uncertain extent.

Figure 2. Fruitafossor in situ from Digimorph.org and used with permission and here colorized to an uncertain extent. All those little white dots could be scattered osteoderms.

The original analysis
nested Fruitafossor between extremely tiny Hadrocodium + Shuotherium and Gobiconodon in a tree topology that does not resemble the topology of the large reptile tree (LRT, 1048 taxa). The authors noted Fruitafossor is “not a eutherian, let alone a xenarthran” despite noting Fruitafossor had tubular molars and xenarthran intervertebral articulations, traits otherwise found only in xenarthrans.

Figure 2. Same specimen from Digimorph.org and rotated to show the teeth better. See figure 3 for a closeup.

Figure 3. Same specimen from Digimorph.org and rotated to show the teeth better. See figure 3 for a closeup. All those little white dots could be scattered osteoderms. Some of this flatness is due to crushing. Some of it is due to this being a wider than deep armored mammal.

Wider than deep
Yes, the Fruitafossor specimen is crushed, but what is shown here indicates a low, wide mammal just getting some armor in the Late Jurassic. And we all know why armor might have been helpful! And this may explain the lateral sprawl of the forelimbs and giant wide humerus, another atavism!

Figure 3. Closeup of figure 2 showing maxilla and dentary in occlusion.

Figure 4. Closeup of figure 2 showing maxilla and dentary in occlusion. If there is a convex ventral dentary it must be imagined because it is not preserved.

By contrast,
the LRT nested Fruitafossor with the horned, armored digging ‘armadillo’ more closely related to BradypusPeltephilus (Fig. 5).

Figure 4. The xenarthran, Peltephilus, compared to Fruitafossor, not to scale, but to similar jaw lengths. Note the drawing from Zhou and Wible does not exactly match what one can see in the photo (Fig. 3). This data needs to be clear and it is not.

Figure 5. The xenarthran, Peltephilus, compared to Fruitafossor, not to scale, but to similar jaw lengths. Note the drawing from Luo and Wible does not exactly match what one can see in the photo (Fig. 3). This data needs to be clear and it is not.

Luo and Wible compared
Fruitafossor to the arboreal and extant Bradypus, but not to the fossorial and extinct Peltephilius (Fig. 5). I would consider that a mistake or an oversight that here overturns their hypothesis of a relationship of Fruitafossor to basalmost mammals.

Figure 5. Several drawings from Zhou and Wible that one must trust for accuracy. The verification data is too fuzzy to validate.

Figure 6. Several drawings from Luo and Wible that one must trust for accuracy. The verification data is too fuzzy to validate. As in other xenarthrans, the ilia actually form a pair of horizontal plates on either side of the long fused and eroded sacrals. Four fingers is a trait shared with Peltephilus. Imagine that rib cage wider and not so deep.

Scattered osteoderms
(Fig. 3) were not mentioned in the text. That’s one more trait shared with the armored xenarthran, Peltephilus. This overlooked relationship of derived xenarthrans moves them into the Jurassic, an era they have never been in before in phylogenetic and chronological analyses. Here placental arboreal and fossorial mammals (prior to condylarths) shared time and space with dinosaurs during the Jurassic and Cretaceous, but have, so far, been underrepresented in the fossil record. That’s changing with re-examination of the data applied to a larger gamut taxon list.

Although the illustrated scapula
(Fig. 1) looks like that of an egg-laying mammal, I will wait for better data to validate that illustration. In the meantime, Fruitafossor has blunt, tubular molars and xenarthran vertebral articulations (among many other xenarthran traits) because it is a xenarthran, not an egg-layer with convergent traits.

References
Luo Z-X and Wible JR 2005. A late Jurassic digging mammal and early mammal diversification. Science 308:103–107.