Wednesday, August 14, 2019

[Ornithology • 2019] Ancient DNA from A 2,500-year-old Caribbean Fossil Places An Extinct Bird (Caracara creightoni) in A Phylogenetic Context

Caracara creightoni

in Oswald, Allen, Witt, et al., 2019. 

• New methods and unique fossil sites offer potential to recover tropical bird aDNA.
• The bird, Caracara creightoni, went extinct upon human arrival in the Caribbean.
 • We obtained mitochondrial genome data from C. creightoni.
Caracara creightoni was sister to the two extant continental Caracara species.
• It shared a common ancestor with extant species during the Pleistocene.

Since the late Pleistocene humans have caused the extinction of species across our planet. Placing these extinct species in the tree of life with genetic data is essential to understand the ecological and evolutionary implications of these losses. While ancient DNA (aDNA) techniques have advanced rapidly in recent decades, aDNA from tropical species, especially birds, has been historically difficult to obtain, leaving a gap in our understanding of the extinction processes that have influenced current distributions and biodiversity. Here we report the recovery of a nearly complete mitochondrial genome from a 2,500 year old (late Holocene) bone of an extinct species of bird, Caracara creightoni, recovered from the anoxic saltwater environment of a blue hole in the Bahamas. Our results suggest that this extinct species is sister (1.6% sequence divergence) to a clade containing the extant C. cheriway and C. plancus. Caracara creightoni shared a common ancestor with these extant species during the Pleistocene (1.2-0.4 MYA) and presumably survived on Cuba when the Bahamas was mostly underwater during Quaternary interglacial intervals (periods of high sea levels). Tropical blue holes have been collecting animals for thousands of years and will continue to improve our understanding of faunal extinctions and distributions. In particular, new aDNA techniques combined with radiocarbon dating from Holocene Bahamian fossils will allow us to place other extinct (species-level loss) and extirpated (population-level loss) vertebrate taxa in improved phylogenetic, evolutionary, biogeographic, and temporal contexts.

Keywords: aDNA, Bahamas, Extinction, Falconiformes, Holocene fossils

phylogeny of focal Caracara species and other members of the Falconidae.

 Jessica A. Oswald, Julia M. Allen, Kelsey E. Witt, Ryan A. Folk, Nancy A. Albury, David W. Steadman and Robert P. Guralnick. 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. DOI: 10.1016/j.ympev.2019.106576