Switching pedal phalanges on Sylviornis

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

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

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

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

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

Figure 1. Sylviornis figure with original pedal phalangeal setup.

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

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

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

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

wiki/Sylviornis

4 thoughts on “Switching pedal phalanges on Sylviornis

  1. Nope, that long element is a classic theropod pedal phalanx II-1, not IV-1. You see that same shape with the slight proximomedial expansion in theropods from ornithomimosaurs to Sinraptor to Gallus, and IV-I is basically always shorter than II-1 and III-1 in these taxa with generic terrestrial feet. Not to say such a misidentification never happens (see my post on Fukuivenator), but this isn’t an example of it.

  2. If you’re correct, then we have an autapomorphy with regard to sister taxa (established with the previous data). I note your examples are not closely related to Sylviornis. I have similar data. Those difference help describe the clade. You allowed for the possibility of exceptions with your comment, ‘basically always’, so you are aware of exceptions. Please get back to me when you have data on more closely related taxa. Then I’ll change the score back to what was originally proposed.

    • Your “previous data” are flawed due in part to errors like this one, so it’s circular reasoning for you to claim your topology based on errors should be evidence against this idea being an error, or that I should compare taxa which your erroneous topology places closer to Sylviornis. My examples were phylogenetically diverse to indicate this morphology for II-1 is very conservative for terrestrial theropods, and Gallus should be a valid example since Sylviornis was most recently placed as a stem-galliform based on more and better characters than yours (Worthy et al., 2017). You can also see the same morphology in megapodiid Leipoa in figure 11 of Worthy et al. (2016) that you made your figure from, btw. I’m not commenting to convince you that you’re wrong, but it’s examples like this, toothy Confuciusornis, etc. that are part of why I don’t trust your findings, which you asked me in a prior post.

  3. This brings up an interesting hypothesis that can only be resolved by adding the skeleton of Leipoa to the LRT. I could not locate one on the Internet. Send one if you have one. Remember, in the LRT megapodes and predatory birds are all basal neognaths. They are closely related to each other. I look forward to working this out.

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