Recovering the Genetic Identity of an Extinct-in-the-Wild Species: The Puzzling Case of the Alagoas Curassow

Abstract

The conservation of many endangered taxa relies on hybrid identification, and when hybrids become morphologically indistinguishable from the parental species, the use of molecular markers can assign individual admixture levels. Here, we present the puzzling case of the extinct in the wild Alagoas Curassow (Pauxi mitu), whose captive population descends from only three individuals. Hybridization with the Razor-billed Curassow (P. tuberosa) began more than eight generations ago, and admixture uncertainty affects the whole population. We applied an analysis framework that combined morphological diagnostic traits, Bayesian clustering analyses using 14 microsatellite loci, and mtDNA haplotypes to assess the ancestry of all individuals that were alive from 2008 to 2012. Simulated data revealed that our microsatellites could accurately assign an individual a hybrid origin until the second backcross generation, which permitted us to identify a pure group among the older, but still reproductive animals. No wild species has ever survived such a severe bottleneck, followed by hybridization, and studying the recovery capability of the selected pure Alagoas Curassow group might provide valuable insights into biological conservation theory.

Haemoproteus paraortalidum n. sp. in captive Black-fronted Piping-guans Aburria jacutinga (Galliformes, Cracidae): High prevalence in a population reintroduced into the wild

“…Currently, five conservation centrers breed this species for reintroduction under the Brazilian Action Plan for the Conservation of Endangered Galliformes (ICMBio, 2008;Oliveira-Jr. et al, 2016). Reintroduction of captive-bred animals is essential to avoid threatened birds from being extinct (Costa et al, 2017;Earnhardt et al, 2014;Hammer and Watson, 2012) and is successful for the Red-billed Curassow (Crax blumenbachii), for example, a Brazilian cracid that has been reintroduced in the Atlantic rainforest for almost 30 years (Bernardo et al, 2011a;São Bernardo et al, 2014).…”

An annotated avian inventory of the Brazilian state of Alagoas, one of the world’s most threatened avifauna

“…Described from a 17 th -century painting (Marcgrave, 1648;Linnaeus, 1766), rediscovered only in the 1950s (Pinto, 1952), and then extinct in the wild during the 1980s (Collar et al, 1992;Silveira et al, 2004), the Alagoas Curassow is now being reintroduced in the wild after a successful captive breeding program (Francisco et al, 2021). Information regarding its puzzling taxonomic history and conservation has been covered in detail elsewhere (Collar et al, 1992;Costa et al, 2017;Silveira et al, 2004Silveira et al, , 2008.…”

Recovered after an extreme bottleneck and saved by ex situ management: Lessons from the Alagoas curassow (Pauxi mitu [Linnaeus, 1766]; Aves, Galliformes, Cracidae)

“…The last reliable record in the wild was in 1979 when five individuals were captured for captive breeding. The current population present in captivity descend from only three of these animals (one male and two females; Costa et al, 2017; Silveira et al, 2004). After a problem of hybridization caused by the lack of pedigree control, in 2008, a wide genetic monitoring program started, and subsequently applying an analyses framework that involved diagnostic morphological and molecular markers, a pure group of individuals was identified within the population with a high level of certainty, which permitted the genetic reconstruction of the captive breeding program (Costa et al, 2017).…”

“…The survival of Alagoas curassow can be attributed to five main factors: (i) the rescue of the last remaining individuals just before species extinction; (ii) the correct reproductive management in captivity; (iii) the fact that founder individuals were not related, as evidenced by an effective population size similar to the number of founders (three; Davanço, 2012); (iv) a rapid demographic expansion, with the second generation presenting 19 individuals, which permitted the genetic variability of the founders to pass to the subsequent generations; and (v) a long‐term genetic monitoring program that contributed to avoiding further genetic variability losses. It resulted in moderate genetic variability, with two to five alleles per microsatellite loci (3.0 ± 0.78), in contrast to 2 to 14 alleles per loci (4.36 ± 3.27) in the closely related razor‐billed curassow, Pauxi tuberosa (Costa et al, 2017).…”