Cyrilavis colburnorum: another barbet, not a stem parrot

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, Figs. 1–3), turns out to be a barbet, very similar to the extant Psilopogon (Fig. 4) and the coeval Septencoracias, all more closely related to toucans and hornbills, than to parrots (Fig. 5), as we learned here. Like the 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. It just hangs out there (Fig. 4). And that’s just the first of many traits (I don’t want to pull a Larry Martin here, especially since he found the generic type).

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

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 (Fig. 2). Here (Fig. 2) the bones are colored for identification and reconstruction using DGS.

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. They assumed their inclusion set incorrectly. So, once again, taxon exclusion messed up their results. It doesn’t matter if you view the subjects first hand or not, if you don’t include their closest sister taxa.

Figure 1. The so-called Green River parrot, Cyrilavis-colburnorum, is actually a barbet, closer to hornbills and toucans.

Figure 1. The so-called Green River parrot, Cyrilavis-colburnorum, is actually a barbet, closer to hornbills and toucans. The lacrimal here appears to be pterygoid+palatine for the top bone and a pterygoid + a triangular bone below the jaw. The actual lacrimal is inside the orbit.  DGS tracing tells us more than the original crude tracing and permits the reconstruction without free handing any bones.

Type specimen: FMNH PA 754, a skeleton (Figs. 1, 2). Referred specimen: (FMNH PA 722, a complete skull and cervicals (Fig. 3).

Figure 3. The referred skull of Cyrilavis, Here it appears that the frontals have collapsed and the lacrimal has popped out of the orbit.

Figure 3. The referred skull of Cyrilavis, Here it appears that the frontals have collapsed and the lacrimal has popped out of the orbit.

 

I have not tested
the type specimen for the genus, Cyrilavis olsoni (Feduccia and Martin 1976), but the mandible in ventral view is short, straight and sharply tipped, unlike that of parrots, but similar to barbets.

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

Figure 4. Skull of the extant barbet, Psilopogon. Note the posteriorly drooping maxilla and compare it to Septencoracias in figure 1.

And lest we forget,
like parrots, barbets likewise have a zygodactyl (pedal digit 4 oriented posteriorly) pes (Fig. 5).

FIgure 5. Psilopogon, is a living barbet from SE Asia.

FIgure 5. Psilopogon, is a living barbet from SE Asia. Note the zygodactyl pes, convergent with parrots.

The authors discuss the clade, Halcyornithidae,
a clade within Pan-Psittaiformes. 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.” 

It would probably be interesting
to reconstruct and test other members of the Halcyornithidae to see if they also nest elsewhere in the LRT. We’ll save that for later.

Figure 4. Subset of the LRT focusing on birds sized by color.

Figure 5. Subset of the LRT focusing on birds sized by color. Parrots, like Ara, are not related to barbets, like Psilopogon.

 

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

 

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