The Caracara Conundrum: Where does the extinct Creighton’s Caracara fit in?

How does it relate to other Caracara species?

It could be a question during a pubquiz: How many species of Caracara are there? The answer to that question depends on your timeframe. Are you thinking about extant species, then the answer is two: the Northern Crested Caracara (Caracara cheriway) and the Southern Crested Caracara (C. plancus). If you extend the count to extinct species, the number quickly rises. Multiple extinct species have been described:

  • C. prelutosa (although it is difficult to distinguish from C. cheriway)
  • C. seymouri
  • C. major
  • C. creightoni
  • C. latebrosa
  • C. tellustris
  • C. lutosa

A recent study, published in the journal Molecular Phylogenetics and Evolution, focused on one of these extinct species – the Creighton’s Caracara (C. creightoni) – and figured out how it relates to the two living species.

caracara

A Southern Crested Caracara in Bolivia © Jente Ottenburghs

 

Blue Hole

The researchers were able to extract DNA from a 2500-year-old fossil of Creighton’s Caracara. This fossil was found in a blue hole (i.e. water-filled sink-hole) on the Bahamas. Fossils in these holes are well-preserved because the water is largely anoxic and sunlight does not penetrate deeply. This lack of oxygen and UV radiation minimizes the amount of DNA damage in the fossils. This allowed the reseachers to reconstruct the nearly complete mitochondrial genome of this species.

Comparing the mitochondrial DNA of Creighton’s Caracara with other species revealed that it is sister to the two living species (see phylogeny below). The divergence occurred between 1.13 and 0.41 million years ago.

1-s2.0-S1055790319301411-ga1_lrg.jpg

Creighton’s Caracara is the sister lineage of both extant Caracara species. From: Oswald et al. (2019) Molecular Phylogenetics and Evolution

 

Extinction

Why the Creighton’s Caracara went extinct is not known. It might have to do with the extinction of other animals on Cuba and the Bahamas. These islands used to contain a variety of large reptiles and mammals, which provided a rich source of carrion for Caracaras (and other scavengers, such as the extinct Condor Gymnogyps varonai). When these large animals disappeared, the Creighton’s Caracara lost an important food source and consequently went extinct.

 

References

Oswald, J. A., Allen, J. M., Witt, K. E., Folk, R. A., Albury, N. A., Steadman, D. W., & Guralnick, R. P. (2019). Ancient DNA from a 2,500-year-old Caribbean fossil places an extinct bird (Caracara creightoni) in a phylogenetic context. Molecular Phylogenetics and Evolution, 140, 106576.

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