The coot: ancestral to chickens, sparrows, parrots and giant stink birds

Fulica atra (Linneaus 1758) is the extant coot, a small water bird with large fleshy feet. Here it nests with Chauna, the screamer, but without such a deadly digit zero. The ascending process of the premaxilla spreads laterally beneath a frontal shield, a decoration on the forehead.

Figure 1. The coot (genus: Fulica) is ancestral to the chicken/parrot clade.

Figure 1. The coot (genus: Fulica) is ancestral to the chicken/parrot clade.

Certainly
an underapprciated bird, given the importance of its transitional morphology between basal storks, like the superficially similar trumpeter Psophia, and the clade of screamers + crakes + chickens + sparrows + parrots + the giant stink birds, Dinornis and Gastornis. The smallest of these became good flyers. The rest never did.

Figure 1. More taxa, updated tree, new clade names.

Figure 1. More taxa, updated tree, new clade names.

This clade
had origins in the Early Cretaceous.

References
Linnaeus C 1758. Systema naturæ per regna tria naturæ, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Tomus I. Editio decima, reformata.

wiki/Chauna
wiki/Fulica

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Dingavis: fangs on a basal bird

Here’s an Early Cretaceous bird
at the base of the Odontornithes (toothed neognaths) with premaxillary and anterior dentary teeth developed into fangs, apparently overlooked by the original authors of Dingavis longimaxilla  (IVPP V20284, O’Connor, Wang and Hu 2016). They were more intrigued by the length of the rostrum and did not appear to delve into the details (Figs. 1,2).

Figure 1. Dingavis longimaxilla in situ nests with Hongshanornis at the base of neognath birds.

Figure 1. Dingavis longimaxilla in situ nests with Hongshanornis at the base of neognath birds. This image is about 3/4 full size, so this is a robin-sized bird.

Maybe they rushed through
Attempting a reconstruction helps the mind sort out some of the problems in crushed fossils such as this one. You can try on one idea after another until one seems to fit. 

Figure 2. Dingavis skull. The large anterior teeth were overlooked in the original description. The naris appears to be quite elongate here.

Figure 2. Dingavis skull. The large anterior teeth were overlooked in the original description. The naris appears to be quite elongate here.

It’s worthwhile to compare Dingavis
to its more plesiomorphic sister, Hongshanornis (Fig. 3). Note the four tiny premaxillary teeth and the others lining the jaws.

That beak tip of Dingavis
is similar by analogy to that of the giant petrel, Macronectes. However, the size differences are too great to draw too much of an analogy.

Figure 3. Hongshanornis skull in situ. Note the four tiny premaxillary teeth, two of which enlarge in Dingavis.

Figure 3. Hongshanornis skull in situ. Note the four tiny premaxillary teeth, two of which enlarge in Dingavis.

Wikipedia reports
“Hongshanornis is a member of the group Hongshanornithidae, to which it lent its name. It is closely related to Longicrusavis, which existed alongside Hongshanornis in the Dawangzhangzi ecosystem” In the LRT these taxa are basal to the Late Cretaceous toothed birds, Hesperornis and Ichthyornis. and so appear to be part of the Odontornithes extending to the Early Cretaceous, shortly after the appearance of Archaeopteryx and other Solnhofen birds.

Figure 4. Hongshanornis in situ with drawing from original paper.

Figure 4. Hongshanornis DNHM D2945, in situ with drawing from original paper. Colors added here.

Wikipedia reports
“In 2016, it was suggested that Dingavis might be cogeneric to the closely related genera Changzuiornis and Juehuaornis [Fig. 5] that might have been found in the same formation, in which case Juehuaornis would have priority.”

Figure 5. Juehuaornis does not have premaxillary teeth, so it is not congeneric with Juehuaornis.

Figure 5. Juehuaornis does not have premaxillary teeth, so it is not congeneric with Juehuaornis.

Lacking large anterior fangs,
Juehuanornis (Fig. 5) is not congeneric with Dingavis. 

References
O’Connor JK, Wang M and Hu H 2016.
A new ornithuromorph (Aves) with an elongate rostrum from the Jehol Biota, and the early evolution of rostralization in birds, Journal of Systematic Palaeontology, DOI: 10.1080/14772019.2015.1129518
Zhou Z and Zhang F 2005. Discovery of an ornithurine bird and its implication for Early Cretaceous avian radiation. PNAS 102(52): 18998-19002. doi:10.1073/pnas.0507106102

wiki/Hongshanornis
wiki/Dingavis

 

Duck Origins

Figure 1. Click to enlarge. Duck origins recovered by the LRT. Duck descendants were long-legged walkers and later waders.

Figure 1. Click to enlarge. Duck origins recovered by the LRT. Duck descendants were long-legged walkers and later waders.

Traditional bird phylogenies
nest ducks (genus: Anas) with chickens (genus: Gallus) and screamers (genus: Anhima) close to the base of all neognath birds. 

In the large reptile tree (LRT, 1158 taxa) ducks are not primitive, but arise from a long series of long-legged, increasingly duck-like ancestors including the widely acknowledged proximal ancestor Presbyornis. Hopefully the illustration above (click to enlarge) will clarify the issue in a simple, graphic fashion, as recovered by the LRT.

This is where morphology provides
a readily visible gradual accumulation of traits in derived taxa that is often missing from DNA studies. And yes, it should be this easy.

Eogranivora has chicken feet and 6 fingers

Higher resolution data
and DGS color overlays reveal that the Early Cretaceous chicken, Eogranivora, has overlooked manual and pedal digits (Fig. 1). Digit zero makes an appearance here. Fusion was much less apparent than traced. Pedal digit 1 was overlooked, despite the tracing of pedal 1.1.

Figure 1. The manus and pes of the Early Cretaceous chicken, Eogranivora. Here digit 0 makes an appearance on the manus along with vestigial digits 4 and 5. On the pes pedal digits 1 (cyan) and 5 (purple) were overlooked. Here DGS reveals them. Overlay changes ever 5 seconds. The process of fusion implied by the drawings is not yet complete under DGS.

Figure 1. The manus and pes of the Early Cretaceous chicken, Eogranivora. Here digit 0 makes an appearance on the manus along with vestigial digits 4 and 5. On the pes pedal digits 1 (cyan) and 5 (purple) were overlooked. Here DGS reveals them. Overlay changes ever 5 seconds. The process of fusion implied by the drawings is not yet complete under DGS.

Earlier we looked at Eogranivora and nested it with Gallus the extant chicken using low-rez data. Here even the skull is updated with plate and counter plate revealing data overlooked by original authors (Figs. 2,3 for those who don’t review updated blog posts).

Figure 1b. Eogranivora skull in situ (plate and counterplate) in higher resolution.

Figure 2. Eogranivora skull in situ (plate and counterplate) in higher resolution.

Figure 1c. Skull of Eogranivora in situ and reconstructed using DGS, replacing a lower resolution attempt. Some details added for the palate here.

Figure 3. Skull of Eogranivora in situ and reconstructed using DGS, replacing a lower resolution attempt. Some details added for the palate here.

Eogranivora edentulata (Zheng et al. 2018; Early Cretaceous, Yixian Fm. Aptian, 125 mya; STM35-3) was earlier referred to Hongshanornis by (Zheng et al. 2011) who found evidence for an avian crop, along with feathers, gastroliths and seeds in the present specimen. Distinct from the holotype of HongshanornisEogranivora is toothless. This specimen is a direct link from the Early Cretaceous to the present day. With larger wings and a smaller body Eogranivora would have been a better flyer than extant chickens.

Figure 2. Gallus, the chicken, nests as a sister to the Early Cretaceous, Eogranivora, also a seed-eater.

Figure 4.. Gallus, the chicken, nests as a sister to the Early Cretaceous, Eogranivora, also a seed-eater. Note the length of the robust scapula.

With robust ribs
and a scapula extending back to the pelvis, Gallus, the chicken stands out from most birds. Eogranivora, if I have this right, also has robust ribs and an extended scapula (Fig. 5). Preservation is a funny thing when plates are split from counter plates. Sometimes we see the bone. Sometimes we see an impression of bone. Sometimes the bone splits down the middle and we see the inside of the bone. Here the parts of the scapula appear to be below and above the ribs, hence, my trepidation.

Figure 5. The crop, gizzard, sternum and scapulae of Eogranivora with DGS color overlays. Some guesswork here.

Figure 5. The crop, gizzard, sternum and scapulae? of Eogranivora with DGS color overlays. Some guesswork here. Some vertical bones apparently cross over and under the horizontal ribs. 

References
Zheng X, O’Connor JK, Wang X, Wang Y and Zhou Z 2018. Reinterpretation of a previously described Jehol bird clarifies early trophic evolution in the Ornithuromorpha. Proceedings of the Royal Society B 285: 20172494
Zheng X-T, Martin LD, Zhou Z-H, Burnham DA, Zhang F-C and Miao D 2011. Fossil evidence of avian crops from the Early Cretaceous of China. Proceedings of the National Academy of Sciences. USA 108: 15 904–907

wiki/Eogranivora
wiki/Gallus

Reconstructing Changchengornis

Changchengornis hengdaoziensis
(Ji et al. 1999, Chiappe et al. 1999; GMV-2129) is an Early Cretaceous relative of Zhongornis and Confuciusornis preserved as a plate and counter plate, flattened, but complete and articulated… with feathers and skin outlines (Figs. 1, 2). 

Figure 1. Changchengornis in situ, plate, counterplate, original drawing and new DGS tracing.

Figure 1. Changchengornis in situ, plate, counterplate, original drawing and new DGS tracing.

Missing from the original tracing
are the postorbital bones, the pubis, some tiny teeth and a series of caudal vertebrae (not a pygostyle) as in other confuciusornithiformes (Fig. 4).

Figure 2. Changchengornis original tracings, counterplate flipped to match plate. DGS found a few more bones than shown here.

Figure 2. Changchengornis original tracings, counterplate flipped to match plate. DGS found a few more bones than shown here.

Here it is reconstructed (Fig. 3).

Figure 2. Changchenornis reconstructed.

Figure 3. Changchenornis reconstructed using DGS.

So far (as I know…)
Changchengornis is the only confuciusornithiform (Fig. 4) with a convex rostrum. It also has the shortest tail. At present this clade only extends from the Late Jurassic to the Early Cretaceous.

Figure 4. Confuciusornithiformes to scale. Note the lack of a pygostyle in the majority of taxa.

Figure 4. Confuciusornithiformes to scale. Note the lack of a pygostyle in these taxa.

References
Ji Q, Chiappe L and Ji S 1999. A new Late Mesozoic confuciusornithid bird from China. Journal of Vertebrate Paleontology 19(1): 1–7.
Chiappe LM, Ji S-A, J Q, Norell MA 1999. Anatomy and systematics of the Confuciusornithidae (Theropoda:Aves) from the Late Mesozoic of northeastern China. Bulletin of the American Museum of Natural History 242: 89pp. PDF

wiki/Changchengornis

Eogranivora: an Early Cretaceous chicken!

Updated February 5, 2018 with higher resolution data of the skull. Not much changed. Eogranivora is still a chicken sister. 

This was predicted
by the large reptile tree (LRT, 1054 taxa, subset Fig. 3) and overlooked by the original authors due to a lack of an accurate tracing of the skull. Extant birds had their origin in the Early Cretaceous… they just have not been discovered there, until now.

Figure 1. Eogranivora from Zheng et al. 2018 with DGS colors added and reconstructed. Except for the longer wings and straight rostrum, most traits found here are also found in Gallus the chicken (figure 2).

Figure 1. Eogranivora from Zheng et al. 2018 with DGS colors added and reconstructed. Except for the longer wings and straight rostrum, most traits found here are also found in Gallus the chicken (figure 2).

Figure 1b. Eogranivora skull in situ (plate and counterplate) in higher resolution.

Figure 1b. Eogranivora skull in situ (plate and counterplate) in higher resolution. Colors correspond to reconstructed skull in figure 1c. Colors sure do clarify skulls like this one.

Figure 1c. Skull of Eogranivora in situ and reconstructed using DGS, replacing a lower resolution attempt. Some details added for the palate here.

Figure 1c. Skull of Eogranivora in situ and reconstructed using DGS, replacing a lower resolution attempt. Some details added for the palate here. It’s still a chicken sister.

Eogranivora edentulata (Zheng et al. 2018; Early Cretaceous, Yixian Fm. Aptian, 125 mya; STM35-3) was earlier referred to Hongshanornis by (Zheng et al. 2011) who found evidence for an avian crop, along with feathers, gastroliths and seeds in the present specimen. Distinct from the holotype of Hongshanornis, Eogranivora is toothless.

Figure 2. Gallus, the chicken, nests as a sister to the Early Cretaceous, Eogranivora, also a seed-eater.

Figure 2. Gallus, the chicken, nests as a sister to the Early Cretaceous, Eogranivora, also a seed-eater.

The authors
included Gallus the chicken (Fig. 2) in their taxon list, but failed to nest the two taxa together… even after noting that Eogranivora was a seed eater. So, this one cannot be attributed to taxon exclusion, but taking a look at their tracing of the specimen (Fig. 1) indicates they put little to no effort into deciphering the crushed bones of this complete and articulated specimen. They could have used a little DGS, which always comes with a reconstruction (Fig. 1 skull, pes).

With larger wings and a smaller body
Eogranivora would have been a better flyer than extant chickens. And that’s to be expected.

Figure 3. Eogranivora nests with Gallus the chicken in the LRT, confirming the origin of Ornithuromorpha back to the Early Cretaceous.

Figure 3. Eogranivora nests with Gallus the chicken in the LRT, confirming the origin of Ornithuromorpha in the Early Cretaceous, which makes it that much easier to have highly derived penguins appear in the Paleocene.

You may remember
the highly derived penguins first appear in the Paleocene. The appearance of volant chickens in the Early Cretaceous makes this easier (more gradual), and falsifies the earlier widely-held hypothesis of a fast radiation of extant birds shortly after the K-T extinction event.

This could have been a big news event.
Unfortunately, it falls to bloggers to make the importance of this fossil widely known.

References
Zheng X, O’Connor JK, Wang X, Wang Y and Zhou Z 2018. Reinterpretation of a previously described Jehol bird clarifies early trophic evolution in the Ornithuromorpha. Proceedings of the Royal Society B 285: 20172494
Zheng X-T, Martin LD, Zhou Z-H, Burnham DA, Zhang F-C and Miao D 2011. Fossil evidence of avian crops from the Early Cretaceous of China. Proceedings of the National Academy of Sciences. USA 108: 15 904–907

wiki/Eogranivora

Birds in the LRT with suggested nomenclature

Updated February 4, 2018 with new taxa and new provisional clade names.

Figure 1. More taxa, updated tree, new clade names.

Figure 1. More taxa, updated tree, new clade names.

Just a moment to update
the bird subset of the large reptile tree (LRT, 1157 taxa). Given the present taxon list, this is the order they fall into using the generalized characters used throughout the LRT. The names applied here are used in traditional studies, but perhaps not following previous definitions. If this cladogram can be validated by other morphological studies, then perhaps these clade names can retain their usefulness.

Does anyone see
in this list two ‘related’ taxa that do not resemble one another more so than any other taxon? If so, that needs to be noted and repaired.