Genetic rediscovery of an ‘extinct’ Galápagos giant tortoise species

Garrick, Ryan C.; Benavides, Edgar; Russello, Michael A.; Gibbs, James P.; Poulakakis, Nikos; Dion, Kirstin; Hyseni, Chaz; Kajdacsi, Brittney; Márquez, Lady; Bahan, Sarah; Ciofi, Claudio; Tapia, Washington; Caccone, Adalgisa

doi:10.1016/j.cub.2011.12.004

Cited by 52 publications

(82 citation statements)

References 7 publications

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“…These strategies are particularly pertinent in the Mascarene Islands and on Madagascar, as well as in the Galápagos. Rewilding and restoration efforts for giant tortoises in the Galápagos are increasingly being evaluated in the context of conservation genetics and the phylogenetic analysis of extant and extinct species (Poulakakis et al 2008Parham 2008;Russello et al 2010;Garrick et al 2012;Hennessy 2014). In the Mascarenes and Seychelles, genetic analysis of the various Cylindraspis and Aldabrachelys taxa, whether classified as species, subspecies, evolutionarily significant units (ESUs), or management units (MUs), has suggested rapid adaptive evolution of these various isolated insular taxa (Austin and Arnold 2001;Austin et al 2003;Gerlach and Rioux Paquette 2014).…”

Section: Island Refugiamentioning

confidence: 99%

“…Charles Darwin saw no live tortoises when he visited in 1835 and only a handful of tortoises appear to have been collected between 1840 and 1847, with final rapid exinction estimated to have occurred in about 1850 (Broom 1929;Steadman 1986). However, hybrid specimens of C. nigra and C. becki have recently been discovered on Volcan Wolf on Isabela, probably as a result of C. nigra being inadvertently released there by whalers prior to the 1830s (as with C. abingdonii), suggesting that the taxon may not yet be fully extinct (Poulakakis et al 2008;Parham 2008;Garrick et al 2012). Some authorities treat this taxon as the nominotypical subspecies of C. nigra, and it has also been referred to variously as C. galapagoensis and C. elephantopus.…”

Section: __testudinidaementioning

confidence: 99%

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Turtles and Tortoises of the World During the Rise and Global Spread of Humanity: First Checklist and Review of Extinct Pleistocene and Holocene Chelonians.

Rhodin¹,

Thomson²,

Georgalis³

et al. 2015

Chelonian Research Monographs

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ABsTrAcT. -We provide a first checklist and review of all recognized taxa of the world's extinct Pleistocene and Holocene (Quaternary) turtles and tortoises that existed during the early rise and global expansion of humanity, and most likely went extinct through a combination of earlier hominin (e.g., Homo erectus, H. neanderthalensis) and later human (H. sapiens) exploitation, as well as being affected by concurrent global or regional climatic and habitat changes. This checklist complements the broader listing of all modern and extant turtles and tortoises by the Turtle Taxonomy Working Group (2014). We provide a comprehensive listing of taxonomy, names, synonymies, and stratigraphic distribution of all chelonian taxa that have gone extinct from approximately the boundary between the Late Pliocene and Early Pleistocene, ca. 2.6 million years ago, up through 1500 AD, at the beginning of modern times. We also provide details on modern turtle and tortoise taxa that have gone extinct since 1500 AD. This checklist currently includes 100 fossil turtle and tortoise taxa, including 84 named and apparently distinct species, and 16 additional taxa that appear to represent additional valid species, but are only identified to genus or family. Modern extinct turtles and tortoises include 8 species, 3 subspecies, and 1 unnamed taxon, for 12 taxa. Of the extinct fossil taxa, terrestrial tortoises of the family Testudinidae (including many large-bodied island forms) are the most numerous, with 60 taxa. When the numbers for fossil tortoises are combined with the 61 modern (living and extinct) species of tortoises, of the 121 tortoise species that have existed at some point since the beginning of the Pleistocene, 69 (57.0%) have gone extinct. This likely reflects the high vulnerability of these large and slow terrestrial (often insular) species primarily to human exploitation. The other large-bodied terrestrial turtles, the 000e.2 Conservation Biology of Freshwater Turtles and Tortoises • Chelonian Research Monographs, No. 5As an addition to the annual checklist of extant modern turtle taxa (Turtle Taxonomy Working Group [TTWG] 2014), we here present an annotated checklist of extinct Pleistocene and Holocene turtle and tortoise species that existed in relatively recent times, prior to 1500 AD, during the history of the rise and global spread of humanity and concurrent global climatic and habitat changes. These species, recorded from archaeological and paleontological sites from the Pleistocene and Holocene epochs (Quaternary period), approximately the last 2.6 million years, are currently considered to be valid, and not synonymous with modern (post-1500 AD) taxa.These fossil species, including some unnamed taxa of indeterminate or undescribed generic or specific allocation, represent the majority of the chelonian diversity that has gone extinct relatively recently. Many of these taxa were likely extirpated by anthropogenic exploitation over the relatively long prehistory of earlier hominin (e.g., Homo erectus, H. neanderthalensi...

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Section: Island Refugiamentioning

confidence: 99%

Section: __testudinidaementioning

confidence: 99%

Turtles and Tortoises of the World During the Rise and Global Spread of Humanity: First Checklist and Review of Extinct Pleistocene and Holocene Chelonians.

Rhodin¹,

Thomson²,

Georgalis³

et al. 2015

Chelonian Research Monographs

View full text Add to dashboard Cite

show abstract

“…To establish the number of genetic clusters within the reference dataset, genotypic clustering analyses were run for K = 9-17, covering a range of K-values identified in previous studies (Russello et al, , 2010Poulakakis et al, 2008;Garrick et al, 2012). STRUCTURE v2.3.3 (Pritchard et al, 2000 was run for 1 Â 10 6 generations with a burn-in of 1 Â 10 5 and five replicate runs using a location prior.…”

Section: Detecting C Abingdoni Ancestry On Vwmentioning

confidence: 99%

“…Genotypes for 500 individuals were simulated in each hybrid classes using HYBRID-LAB (Nielsen et al, 2006) and analyzed in STRUCTURE to characterize Q-value frequency distributions. The approach of Garrick et al (2012) was used to define criteria for hybrid classification. Theoretical predictions suggested five parental crosses were involved in generating individuals with C. abingdoni ancestry (Table S2).…”

Section: Characterizing C Abingdoni Ancestry On Vwmentioning

confidence: 99%

The genetic legacy of Lonesome George survives: Giant tortoises with Pinta Island ancestry identified in Galápagos

Edwards

Benavides

Garrick

et al. 2013

Biological Conservation

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a b s t r a c tThe death of Lonesome George, the last known purebred individual of Chelonoidis abingdoni native to Pinta Island, marked the extinction of one of 10 surviving giant tortoise species from the Galápagos Archipelago. Using a DNA reference dataset including historical C. abingdoni and >1600 living Volcano Wolf tortoise samples, a site on Isabela Island known to harbor hybrid tortoises, we discovered 17 individuals with ancestry in C. abingdoni. These animals belong to various hybrid categories, including possible first generation hybrids, and represent multiple, unrelated individuals. Their ages and relative abundance suggest that additional hybrids and conceivably purebred C. abingdoni individuals still occur on Volcano Wolf. Spatial analyses suggest locations where additional individuals with C. abingdoni ancestry are most likely to be recovered, consistent with historical records of human movement of tortoises. These results provide an opportunity for species recovery of Pinta Island tortoises using individuals with C. abingdoni ancestry.

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“…O fenômeno da hibridização é frequente e tem atraído a atenção de inúmeros pesquisadores e naturalistas que ao longo do tempo registraram sua ocorrência em diversos grupos de vertebrados como tubarões, répteis e mamíferos (Wilson, 1974;Van Gelder, 1977;Morgan et al, 2011;Garrick et al, 2012). Os indivíduos híbri-dos não são necessariamente inférteis, como se acreditava anteriormente.…”

Section: Discussionunclassified

Hybridization phenomenon in cetacean and pinniped species

Schaurich

Lopes

Oliveira

2012

Neotropical Biology and Conservation

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ResumoO hibridismo é resultado do cruzamento entre indivíduos com conjuntos gênicos diferentes e isolados considerados como espécies que geram prole, frequentemente, infértil. As consequências evolutivas desse fenômeno dependem da aptidão, frequência de ocorrência do híbrido, mecanismos de isolamento reprodutivo e processos de especiação que envolvem as espécies parentais. Nos mamíferos, híbridos têm sido registrados em espécies aquáticas e terrestres, ocorrendo frequentemente em cativeiro e na natureza. Nesse sentido, esta revisão bibliográfica teve como objetivo verificar os casos de híbridos ocorridos em cetáceos e pinípedes publicados na literatura científica entre 1940 e 2010. Ao todo, foram encontrados 1.201 híbridos formalmente reportados em 37 publicações. Para os cetáceos, foram registrados 57 híbridos (natureza = 27; cativeiro = 30) e para os pinípedes, 1.144 híbridos (natureza = 1.137; cativeiro = 7). Uma possível explicação para esse fenômeno em vida livre seria a proximidade filogenética e a potencial falta de parceiros reprodutivos nas espécies que tiveram suas populações reduzidas devido à caça comercial ocorrida no passado. Esse fato é válido para os pinípedes, mas especialmente verdadeiro para a baleia-azul, Balaenoptera musculus. No caso dos pinípedes, também é importante ressaltar que cerca de 99% dos híbridos ocorreram nas ilhas subantárticas e em colônias reprodutivas simpátricas, o que facilitaria a hibridização. Como resultado deste fenômeno pode-se mencionar a potencial depressão por exocruzamento, fato que pode levar à perda de variabilidade genética, diminuição do potencial evolutivo e aumento no risco de extinção.Palavras-chave: mamíferos aquáticos, Cetartiodactyla, Carnivora, híbridos, depressão por exocruzamento, ameaça à conservação. AbstractThe hybridism is the result of mating between two individuals from different and reproductively isolated gene pools accepted as species that usually generate infertile offspring. The evolutionary consequences of this phenomenon vary depending on the mating system, hybrid's frequency, the degree of reproductive isolation and the genetic differences between the parental species as well as their speciation process. Hybrids have been recorded frequently in aquatic and terrestrial mammals, both in nature and captivity. We review studies published in peer-reviewed journals between 1940 and 2010, in which hybrid cases were reported for cetaceans and pinnipeds. We found 37 scientific papers recording 1,201 hybrids: 57 in cetaceans (nature = 27; captivity = 30) and 1,144 in pinnipeds (nature = 1,137; captivity = 7). A possible explanation for this phenomenon in the wild could be the close phylogenetic relatedness between parental species and also the potential absence of conspecific breeding partners. This last factor could be a result of population decline due to commercial exploitation occurred in the past. This fact is valid for pinnipeds, but especially true for blue whales, Balaenoptera musculus. It is important to note that about Van Gelder, 1977;...

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Genetic rediscovery of an ‘extinct’ Galápagos giant tortoise species

Cited by 52 publications

References 7 publications

Turtles and Tortoises of the World During the Rise and Global Spread of Humanity: First Checklist and Review of Extinct Pleistocene and Holocene Chelonians.

Turtles and Tortoises of the World During the Rise and Global Spread of Humanity: First Checklist and Review of Extinct Pleistocene and Holocene Chelonians.

The genetic legacy of Lonesome George survives: Giant tortoises with Pinta Island ancestry identified in Galápagos

Hybridization phenomenon in cetacean and pinniped species

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