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Arvind Varsani - One of the best experts on this subject based on the ideXlab platform.
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Identification of Circovirus Genome in a Chinstrap Penguin (Pygoscelis antarcticus) and Adélie Penguin (Pygoscelis adeliae) on the Antarctic Peninsula.
Viruses, 2020Co-Authors: Hila Levy, Steven R. Fiddaman, Anni Djurhuus, Caitlin Black, Simona Kraberger, Adrian Smith, Tom Hart, Arvind VarsaniAbstract:Circoviruses infect a variety of animal species and have small (~1.8–2.2 kb) circular single-stranded DNA genomes. Recently a penguin circovirus (PenCV) was identified associated with an Adelie Penguin (Pygoscelis adeliae) with feather disorder and in the cloacal swabs of three asymptomatic Adelie Penguins at Cape Crozier, Antarctica. A total of 75 cloacal swab samples obtained from adults and chicks of three species of penguin (genus: Pygoscelis) from seven Antarctic breeding colonies (South Shetland Islands and Western Antarctic Peninsula) in the 2015−2016 breeding season were screened for PenCV. We identified new variants of PenCV in one Adelie Penguin and one Chinstrap Penguin (Pygoscelis antarcticus) from Port Charcot, Booth Island, Western Antarctic Peninsula, a site home to all three species of Pygoscelid penguins. These two PenCV genomes (length of 1986 nucleotides) share > 99% genome-wide nucleotide identity with each other and share ~87% genome-wide nucleotide identity with the PenCV sequences described from Adelie Penguins at Cape Crozier ~4400 km away in East Antarctica. We did not find any evidence of recombination among PenCV sequences. This is the first report of PenCV in Chinstrap Penguins and the first detection outside of Ross Island, East Antarctica. Given the limited knowledge on Antarctic animal viral diversity, future samples from Antarctic wildlife should be screened for these and other viruses to determine the prevalence and potential impact of viral infections.
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identification of a polyomavirus in weddell seal leptonychotes weddellii from the ross sea antarctica
Archives of Virology, 2017Co-Authors: Simona Kraberger, Arvind Varsani, Greg Frankfurter, Daisy Stainton, Maketalena F Male, Jennifer M BurnsAbstract:Viruses are ubiquitous in nature, however, very few have been identified that are associated with Antarctic animals. Here we report the identification of a polyomavirus in the kidney tissue of a deceased Weddell seal from the Ross Sea, Antarctica. The circular genome (5186 nt) has typical features of polyomaviruses with a small and larger T-antigen open reading frames (ORFs) and three ORFs encoding VP1, VP2 and VP3 capsid proteins. The genome of the Weddell seal polyomavirus (WsPyV) shares 85.4% genome-wide pairwise identity with a polyomavirus identified in a California sea lion. To our knowledge WsPyV is the first viral genome identified in Antarctic pinnipeds and the third polyomavirus to be identified from an Antarctic animal, the other two being from Adelie penguin (Pygoscelis adeliae) and a sharp-spined notothen (Trematomus pennellii), both sampled in the Ross sea. The GenBank accession number: KX533457.
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identification of an avian polyomavirus associated with adelie penguins Pygoscelis adeliae
Journal of General Virology, 2015Co-Authors: Simona Kraberger, Arvind Varsani, Elizabeth L Porzig, Scott Jennings, Kata Farkas, Laurel Julian, Melanie Massaro, Grant BallardAbstract:Little is known about viruses associated with Antarctic animals, although they are probably widespread. We recovered a novel polyomavirus from Adelie penguin (Pygoscelis adeliae) faecal matter sampled in a subcolony at Cape Royds, Ross Island, Antarctica. The 4988 nt Adelie penguin polyomavirus (AdPyV) has a typical polyomavirus genome organization with three ORFs that encoded capsid proteins on the one strand and two non-structural protein-coding ORFs on the complementary strand. The genome of AdPyV shared ~60 % pairwise identity with all avipolyomaviruses. Maximum-likelihood phylogenetic analysis of the large T-antigen (T-Ag) amino acid sequences showed that the T-Ag of AdPyV clustered with those of avipolyomaviruses, sharing between 48 and 52 % identities. Only three viruses associated with Adelie penguins have been identified at a genomic level, avian influenza virus subtype H11N2 from the Antarctic Peninsula and, respectively, Pygoscelis adeliae papillomavirus and AdPyV from capes Crozier and Royds on Ross Island.
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a novel papillomavirus in adelie penguin Pygoscelis adeliae faeces sampled at the cape crozier colony antarctica
Journal of General Virology, 2014Co-Authors: Arvind Varsani, Simona Kraberger, Elizabeth L Porzig, Scott Jennings, Laurel Julian, Melanie Massaro, Grant Ballard, Annie Pollard, David G AinleyAbstract:Papillomaviruses are epitheliotropic viruses that have circular dsDNA genomes encapsidated in non-enveloped virions. They have been found to infect a variety of mammals, reptiles and birds, but so far they have not been found in amphibians. Using a next-generation sequencing de novo assembly contig-informed recovery, we cloned and Sanger sequenced the complete genome of a novel papillomavirus from the faecal matter of Adelie penguins (Pygoscelis adeliae) nesting on Ross Island, Antarctica. The genome had all the usual features of a papillomavirus and an E9 ORF encoding a protein of unknown function that is found in all avian papillomaviruses to date. This novel papillomavirus genome shared ~60 % pairwise identity with the genomes of the other three known avian papillomaviruses: Fringilla coelebs papillomavirus 1 (FcPV1), Francolinus leucoscepus papillomavirus 1 (FlPV1) and Psittacus erithacus papillomavirus 1. Pairwise identity analysis and phylogenetic analysis of the major capsid protein gene clearly indicated that it represents a novel species, which we named Pygoscelis adeliae papillomavirus 1 (PaCV1). No evidence of recombination was detected in the genome of PaCV1, but we did detect a recombinant region (119 nt) in the E6 gene of FlPV1 with the recombinant region being derived from ancestral FcPV1-like sequences. Previously only paramyxoviruses, orthomyxoviruses and avian pox viruses have been genetically identified in penguins; however, the majority of penguin viral identifications have been based on serology or histology. This is the first report, to our knowledge, of a papillomavirus associated with a penguin species.
Simona Kraberger - One of the best experts on this subject based on the ideXlab platform.
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Identification of Circovirus Genome in a Chinstrap Penguin (Pygoscelis antarcticus) and Adélie Penguin (Pygoscelis adeliae) on the Antarctic Peninsula.
Viruses, 2020Co-Authors: Hila Levy, Steven R. Fiddaman, Anni Djurhuus, Caitlin Black, Simona Kraberger, Adrian Smith, Tom Hart, Arvind VarsaniAbstract:Circoviruses infect a variety of animal species and have small (~1.8–2.2 kb) circular single-stranded DNA genomes. Recently a penguin circovirus (PenCV) was identified associated with an Adelie Penguin (Pygoscelis adeliae) with feather disorder and in the cloacal swabs of three asymptomatic Adelie Penguins at Cape Crozier, Antarctica. A total of 75 cloacal swab samples obtained from adults and chicks of three species of penguin (genus: Pygoscelis) from seven Antarctic breeding colonies (South Shetland Islands and Western Antarctic Peninsula) in the 2015−2016 breeding season were screened for PenCV. We identified new variants of PenCV in one Adelie Penguin and one Chinstrap Penguin (Pygoscelis antarcticus) from Port Charcot, Booth Island, Western Antarctic Peninsula, a site home to all three species of Pygoscelid penguins. These two PenCV genomes (length of 1986 nucleotides) share > 99% genome-wide nucleotide identity with each other and share ~87% genome-wide nucleotide identity with the PenCV sequences described from Adelie Penguins at Cape Crozier ~4400 km away in East Antarctica. We did not find any evidence of recombination among PenCV sequences. This is the first report of PenCV in Chinstrap Penguins and the first detection outside of Ross Island, East Antarctica. Given the limited knowledge on Antarctic animal viral diversity, future samples from Antarctic wildlife should be screened for these and other viruses to determine the prevalence and potential impact of viral infections.
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identification of a polyomavirus in weddell seal leptonychotes weddellii from the ross sea antarctica
Archives of Virology, 2017Co-Authors: Simona Kraberger, Arvind Varsani, Greg Frankfurter, Daisy Stainton, Maketalena F Male, Jennifer M BurnsAbstract:Viruses are ubiquitous in nature, however, very few have been identified that are associated with Antarctic animals. Here we report the identification of a polyomavirus in the kidney tissue of a deceased Weddell seal from the Ross Sea, Antarctica. The circular genome (5186 nt) has typical features of polyomaviruses with a small and larger T-antigen open reading frames (ORFs) and three ORFs encoding VP1, VP2 and VP3 capsid proteins. The genome of the Weddell seal polyomavirus (WsPyV) shares 85.4% genome-wide pairwise identity with a polyomavirus identified in a California sea lion. To our knowledge WsPyV is the first viral genome identified in Antarctic pinnipeds and the third polyomavirus to be identified from an Antarctic animal, the other two being from Adelie penguin (Pygoscelis adeliae) and a sharp-spined notothen (Trematomus pennellii), both sampled in the Ross sea. The GenBank accession number: KX533457.
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identification of an avian polyomavirus associated with adelie penguins Pygoscelis adeliae
Journal of General Virology, 2015Co-Authors: Simona Kraberger, Arvind Varsani, Elizabeth L Porzig, Scott Jennings, Kata Farkas, Laurel Julian, Melanie Massaro, Grant BallardAbstract:Little is known about viruses associated with Antarctic animals, although they are probably widespread. We recovered a novel polyomavirus from Adelie penguin (Pygoscelis adeliae) faecal matter sampled in a subcolony at Cape Royds, Ross Island, Antarctica. The 4988 nt Adelie penguin polyomavirus (AdPyV) has a typical polyomavirus genome organization with three ORFs that encoded capsid proteins on the one strand and two non-structural protein-coding ORFs on the complementary strand. The genome of AdPyV shared ~60 % pairwise identity with all avipolyomaviruses. Maximum-likelihood phylogenetic analysis of the large T-antigen (T-Ag) amino acid sequences showed that the T-Ag of AdPyV clustered with those of avipolyomaviruses, sharing between 48 and 52 % identities. Only three viruses associated with Adelie penguins have been identified at a genomic level, avian influenza virus subtype H11N2 from the Antarctic Peninsula and, respectively, Pygoscelis adeliae papillomavirus and AdPyV from capes Crozier and Royds on Ross Island.
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a novel papillomavirus in adelie penguin Pygoscelis adeliae faeces sampled at the cape crozier colony antarctica
Journal of General Virology, 2014Co-Authors: Arvind Varsani, Simona Kraberger, Elizabeth L Porzig, Scott Jennings, Laurel Julian, Melanie Massaro, Grant Ballard, Annie Pollard, David G AinleyAbstract:Papillomaviruses are epitheliotropic viruses that have circular dsDNA genomes encapsidated in non-enveloped virions. They have been found to infect a variety of mammals, reptiles and birds, but so far they have not been found in amphibians. Using a next-generation sequencing de novo assembly contig-informed recovery, we cloned and Sanger sequenced the complete genome of a novel papillomavirus from the faecal matter of Adelie penguins (Pygoscelis adeliae) nesting on Ross Island, Antarctica. The genome had all the usual features of a papillomavirus and an E9 ORF encoding a protein of unknown function that is found in all avian papillomaviruses to date. This novel papillomavirus genome shared ~60 % pairwise identity with the genomes of the other three known avian papillomaviruses: Fringilla coelebs papillomavirus 1 (FcPV1), Francolinus leucoscepus papillomavirus 1 (FlPV1) and Psittacus erithacus papillomavirus 1. Pairwise identity analysis and phylogenetic analysis of the major capsid protein gene clearly indicated that it represents a novel species, which we named Pygoscelis adeliae papillomavirus 1 (PaCV1). No evidence of recombination was detected in the genome of PaCV1, but we did detect a recombinant region (119 nt) in the E6 gene of FlPV1 with the recombinant region being derived from ancestral FcPV1-like sequences. Previously only paramyxoviruses, orthomyxoviruses and avian pox viruses have been genetically identified in penguins; however, the majority of penguin viral identifications have been based on serology or histology. This is the first report, to our knowledge, of a papillomavirus associated with a penguin species.
Andrés Barbosa - One of the best experts on this subject based on the ideXlab platform.
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Isotopic niches of sympatric Gentoo and Chinstrap Penguins: evidence of competition for Antarctic krill?
Polar Biology, 2018Co-Authors: Danijela Dimitrijević, Vitor H. Paiva, José Seco, Filipe R. Ceia, Nesho Chipev, Tiago Valente, Andrés Barbosa, Jaime A Ramos, José C. XavierAbstract:As climate change, among other factors, is increasingly affecting Antarctic marine systems, competition for prey may increase between predators, particularly in the Antarctic Peninsula which has warmed more than elsewhere. Under such a context, we tested the feeding and trophic ecology of Gentoo ( Pygoscelis papua ) and Chinstrap ( Pygoscelis antarctica ) penguins breeding in sympatry at Livingston Island (Antarctic Peninsula) in a single season. We compared the diets of adults (from faecal samples, and stable isotopes in feathers and blood) and chicks (from stomach contents, and stable isotopes in down feathers, toenails and muscles of chicks that had died of unknown causes). Antarctic krill Euphausia superba dominated the diet of both species, although Gentoo Penguins fed on larger Antarctic krill than did Chinstrap Penguins. Stable isotope analyses of adult tissues revealed that both species fed at different niches in successive years, as depicted by the different levels δ ^13C in feathers (showing values from the previous breeding season) and whole blood (showing values from the current season). Tissues collected from chicks confirmed their diet over different time scales (i.e. days to weeks): Gentoo Penguins fed at a higher trophic level (possibly due to a more varied diet) and in different habitats than Chinstrap Penguins, providing evidence of isotopic niche separation of penguins. Our results may be relevant to the monitoring programmes of the Convention on the Conservation of Antarctic Marine Living Resources (CCAMLR) and suggest that adult scats, and stomach contents and tissues of recently died chicks, can be used in such programmes.
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Gastrointestinal helminths of Adélie penguins ( Pygoscelis adeliae ) from Antarctica
Polar Research, 2016Co-Authors: Julia Inés Diaz, Bruno Fusaro, Lucrecia Longarzo, Néstor Rubén Coria, Virginia Vidal, Verónica L. D’amico, Andrés BarbosaAbstract:Knowledge about parasitic organisms in Antarctica is scarce and fragmentary. The study reported here adds to the knowledge of gastrointestinal parasites of the Adelie penguin ( Pygoscelis adeliae ) (Sphenisciformes), from 25 de Mayo/King George Island (South Shetlands), Bahia Esperanza (Hope Bay) and Avian Island (Antarctica). Thirty-five freshly dead specimens (20 chicks and 15 adults) were collected from December 2007 to December 2014 and examined for internal macroparasites. Three adult parasite species were found: one Cestoda, Parorchites zederi , and two Nematoda, Stegophorus macronectes and Tetrameres sp. Immature Tetrabothrius sp. were found in hosts from Avian Island. Helminth communities are known to be related to host feeding behaviours. Low parasite richness observed in Adelie penguins could be related to the stenophagic and pelagic diet of this host species, which feeds almost exclusively on krill. Keywords: Parorchites zederi ; Stegophorus macronectes ; Tetrameres sp.; parasites; ecosystem health. (Published: 16 June 2016) Citation: Polar Research 2016, 35 , 28516,http://dx.doi.org/10.3402/polar.v35.28516
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age related differences in the gastrointestinal microbiota of chinstrap penguins Pygoscelis antarctica
PLOS ONE, 2016Co-Authors: Andrés Barbosa, Julia Inés Diaz, Francisco Valera, Jesus Benzal, Ana Martinez, Vanessa Balague, Miguel Motas, Alex Mira, Carlos PedrosalioAbstract:The gastrointestinal tract microbiota is known to play very important roles in the well being of animals. It is a complex community composed by hundreds of microbial species interacting closely among them and with their host, that is, a microbial ecosystem. The development of high throughput sequencing techniques allows studying the diversity of such communities in a realistic way and considerable work has been carried out in mammals and some birds such as chickens. Wild birds have received less attention and in particular, in the case of penguins, only a few individuals of five species have been examined with molecular techniques. We collected cloacal samples from Chinstrap penguins in the Vapour Col rookery in Deception Island, Antarctica, and carried out pyrosequencing of the V1-V3 region of the 16S rDNA in samples from 53 individuals, 27 adults and 26 chicks. This provided the first description of the Chinstrap penguin gastrointestinal tract microbiota and the most extensive in any penguin species. Firmicutes, Bacteoridetes, Proteobacteria, Fusobacteria, Actinobacteria, and Tenericutes were the main components. There were large differences between chicks and adults. The former had more Firmicutes and the latter more Bacteroidetes and Proteobacteria. In addition, adults had richer and more diverse bacterial communities than chicks. These differences were also observed between parents and their offspring. On the other hand, nests explained differences in bacterial communities only among chicks. We suggest that environmental factors have a higher importance than genetic factors in the microbiota composition of chicks. The results also showed surprisingly large differences in community composition with other Antarctic penguins including the congeneric Adelie and Gentoo penguins.
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Gastrointestinal helminths of Adélie penguins (Pygoscelis adeliae) from Antarctica
Norwegian Polar Institute, 2016Co-Authors: Julia Inés Diaz, Bruno Fusaro, Lucrecia Longarzo, Néstor Rubén Coria, Virginia Vidal, Verónica D'amico, Andrés BarbosaAbstract:Knowledge about parasitic organisms in Antarctica is scarce and fragmentary. The study reported here adds to the knowledge of gastrointestinal parasites of the Adélie penguin (Pygoscelis adeliae) (Sphenisciformes), from 25 de Mayo/King George Island (South Shetlands), Bahia Esperanza (Hope Bay) and Avian Island (Antarctica). Thirty-five freshly dead specimens (20 chicks and 15 adults) were collected from December 2007 to December 2014 and examined for internal macroparasites. Three adult parasite species were found: one Cestoda, Parorchites zederi, and two Nematoda, Stegophorus macronectes and Tetrameres sp. Immature Tetrabothrius sp. were found in hosts from Avian Island. Helminth communities are known to be related to host feeding behaviours. Low parasite richness observed in Adélie penguins could be related to the stenophagic and pelagic diet of this host species, which feeds almost exclusively on krill
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sex identification in gentoo Pygoscelis papua and chinstrap Pygoscelis antarctica penguins can flow cytometry be used as a reliable identification method
Journal of Experimental Marine Biology and Ecology, 2014Co-Authors: Joao Loureiro, José Seco, Nesho Chipev, Tiago Valente, Andrés Barbosa, José C. Xavier, Daniela Tavares, Sonia Ferreira, Phil N TrathanAbstract:An important scientific question in ecology is how to differentiate males from females that have similar morphology. In penguins, due to their monomorphic plumage, it is difficult to determine gender. So far, most approaches to address this problem have focused on using sex based discriminant functions combined with DNA based tools as a validation method. As discriminant functions can be species and locality specific, in this study we explored the feasibility of using flow cytometry to determine the sex of two species of penguins, Pygoscelis antarctica and Pygoscelis papua. Our results for sex assessment determined by flow cytometry were compared with those obtained using morphological characters (bill length and depth), and DNA based methods (using the PL/PR primer pair) were used to validate both approaches. For both species, statistically significant differences were observed between males and females, with males presenting on average 2.1% more nuclear DNA than females. Flow cytometry enabled similar or better rates of correct sex assignment (86.4% and 80.0%) than sex discriminant functions (31.8% and 90.0%) for P. antarctica and P. papua, respectively, and thus may be considered as a promising alternative to the use of morphological data for sex identification. Nevertheless, some individuals with intermediate genome size values were observed, which increased the difficulty of categorically assigning their sex. Therefore, flow cytometry alone cannot be considered in all cases, but if used together with DNA-based methods in targeted samples, it can be used to efficiently estimate the gender of, at least, these two penguin species, with the potential to be used in other species.
Michael J Polito - One of the best experts on this subject based on the ideXlab platform.
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seasonal consistency and individual variation in foraging strategies differ among and within Pygoscelis penguin species in the antarctic peninsula region
Marine Biology, 2017Co-Authors: Rachael Herman, Maria Virginia Petry, Tom Hart, Fernanda Caminha Leal Valls, Wayne Z Trivelpiece, Michael J PolitoAbstract:Past research during the breeding season in the Antarctic Peninsula region indicates that gentoo penguins (Pygoscelis papua) are generalist foragers whereas Adelie (P. adeliae) and chinstrap (P. antarcticus) penguins tend to specialize on Antarctic krill (Euphausia superba). However, little is known about the degree of temporal consistency in the diets and foraging habitats of these three species, particularly at the individual level. Such year-round and inter-annual dietary understanding is important to help interpret contrasting trends in their populations. We used carbon and nitrogen stable isotope analysis of blood and feathers to evaluate seasonal shifts in diet and individual foraging consistency within Pygoscelis penguin species breeding in the South Shetland Islands as well as among three geographically distinct gentoo penguin populations in the western Antarctic Peninsula and South Shetland Islands. We found that gentoo penguins exhibited a generalist foraging strategy with individual consistency, Adelie penguins exhibited an intermediate generalist foraging strategy with little individual consistency, and chinstrap penguins exhibited a specialized diet with little inter-individual variation. Our results also indicated that all three species have greater variation in foraging habitat use during the post-breeding season compared to the breeding season. Finally, we observed differences in the degree of seasonal shifts in population level diet and consistency in foraging strategies at the individual level across the three gentoo penguin populations examined. This suggests that Pygoscelis penguins can differ in diets and foraging habitat use not only at the population level among species, sites, and seasons, but also in the level of variation within populations, and in the degree of seasonal consistency among individuals.
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spatial and isotopic niche partitioning during winter in chinstrap and adelie penguins from the south shetland islands
Ecosphere, 2015Co-Authors: Jefferson T Hinke, Michael J Polito, Wayne Z Trivelpiece, Michael E Goebel, Sharon Jarvis, Christian S Reiss, Simon R Thorrold, George M WattersAbstract:Closely related species with similar ecological requirements should exhibit segregation along spatial, temporal, or trophic niche axes to limit the degree of competitive overlap. For migratory marine organisms like seabirds, assessing such overlap during the non-breeding period is difficult because of long-distance dispersal to potentially diffuse foraging habitats. Miniaturization of geolocation devices and advances in stable isotope analysis (SIA), however, provide a robust toolset to quantitatively track the movements and foraging niches of wide ranging marine animals throughout much of their annual cycle. We used light-based geolocation tags and analyzed stable carbon and nitrogen isotopes from tail feathers to simultaneously characterize winter movements, habitat utilization, and overlap of spatial and isotopic niches of migratory chinstrap (Pygoscelis antarctica) and Adelie (P. adeliae) penguins during the austral winter of 2012. Chinstrap penguins exhibited a higher diversity of movements and occup...
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a reversal of fortunes climate change winners and losers in antarctic peninsula penguins
Scientific Reports, 2015Co-Authors: Gemma V Clucas, Ron Naveen, Michael J Dunn, Gareth J Dyke, Steven D Emslie, Michael J Polito, Oliver G Pybus, Alex Rogers, Tom HartAbstract:Climate change is a major threat to global biodiversity. Antarctic ecosystems are no exception. Investigating past species responses to climatic events can distinguish natural from anthropogenic impacts. Climate change produces ‘winners’, species that benefit from these events and ‘losers’, species that decline or become extinct. Using molecular techniques, we assess the demographic history and population structure of Pygoscelis penguins in the Scotia Arc related to climate warming after the Last Glacial Maximum (LGM). All three pygoscelid penguins responded positively to post-LGM warming by expanding from glacial refugia, with those breeding at higher latitudes expanding most. Northern (Pygoscelis papua papua) and Southern (Pygoscelis papua ellsworthii) gentoo sub-species likely diverged during the LGM. Comparing historical responses with the literature on current trends, we see Southern gentoo penguins are responding to current warming as they did during post-LGM warming, expanding their range southwards. Conversely, Adelie and chinstrap penguins are experiencing a ‘reversal of fortunes’ as they are now declining in the Antarctic Peninsula, the opposite of their response to post-LGM warming. This suggests current climate warming has decoupled historic population responses in the Antarctic Peninsula, favoring generalist gentoo penguins as climate change ‘winners’, while Adelie and chinstrap penguins have become climate change ‘losers’.
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a simplified method of determining the sex of Pygoscelis penguins using bill measurements
Marine ornithology, 2012Co-Authors: Michael J Polito, Tom Hart, Gemma V Clucas, Wayne Z TrivelpieceAbstract:We examined sexual dimorphism in bill size in adult Adelie Penguins Pygoscelis adeliae, adult Chinstrap Penguins P. antarctica and adult and juvenile Gentoo Penguins P. papua at King George Island, Antarctica, using a DNA-based molecular sexing technique. Bill length and depth were the most consistent dimorphic character examined, with measurements 5.4%–11.5% larger in males than in females, on average. Within breeding pairs sampled, male Chinstrap and Gentoo Penguins had consistently longer and deeper bills than their mates, although bill measurement overlapped between sexes at the population level. We used bill measurements to calculate species- and age-specific discriminant functions that correctly classified 83.2%–96.7% of the individuals in our study following cross-validation. The discriminant functions derived from this analysis provide a practical method of sex determination for all three Pygoscelis penguin species in the South Shetland Islands where they breed sympatrically. Posterior probability analysis can also be used to identify individuals that are likely to be incorrectly classified using discriminant function analysis, allowing DNA-based tests for gender to be reserved for targeted use. Furthermore, we report raw morphometric data to facilitate future analysis and discriminant function improvement
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dietary isotopic discrimination in gentoo penguin Pygoscelis papua feathers
Polar Biology, 2011Co-Authors: Michael J Polito, Stephanie Abel, Craig R Tobias, Steven D EmslieAbstract:Feathers are used commonly for stable isotope analysis to assess the foraging ecology and migration patterns of birds. However, these studies often require knowledge of species-specific feather isotopic discrimination factors (the differences in isotopic ratios between a species’ diet and feathers), which can be influenced by a species’ physiological state during molt. In this study, we determined the isotopic discrimination factors (Δ13Cdiet−feather and Δ15Ndiet−feather) between adult gentoo penguin (Pygoscelis papua) diet and feathers in a controlled study. In addition, we tested whether molt duration or the magnitude of voluntary dietary reduction during molt influenced isotopic discrimination, as previous studies have found that nutritional stress can exaggerate 15N enrichment and in some cases lead to 13C depletion in feathers. Contrary to this hypothesis, we found no effect of molt duration or dietary reduction on discrimination factors, suggesting that isotopic discrimination is not linearly related to these measures of fasting intensity in penguins. Furthermore, we found that the range of Δ15Ndiet−feather found in several species of penguins, which fast while they molt, was similar to discrimination factors in fish-eating birds, which do not fast during molt. It is likely that species-specific metabolic adaptations that limit nutritional stress while fasting and variation in their relative reliance on endogenous vs. dietary pools during feather growth may confound the use of Δ15Ndiet−feather as a general measure of nutritional stress when comparing among species.
Tom Hart - One of the best experts on this subject based on the ideXlab platform.
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A global population assessment of the Chinstrap penguin (Pygoscelis antarctica).
Scientific reports, 2020Co-Authors: Noah Strycker, Tom Hart, Michael Wethington, Alex Borowicz, Steve Forrest, Chandi Witharana, Heather J. LynchAbstract:Using satellite imagery, drone imagery, and ground counts, we have assembled the first comprehensive global population assessment of Chinstrap penguins (Pygoscelis antarctica) at 3.42 (95th-percentile CI: [2.98, 4.00]) million breeding pairs across 375 extant colonies. Twenty-three previously known Chinstrap penguin colonies are found to be absent or extirpated. We identify five new colonies, and 21 additional colonies previously unreported and likely missed by previous surveys. Limited or imprecise historical data prohibit our assessment of population change at 35% of all Chinstrap penguin colonies. Of colonies for which a comparison can be made to historical counts in the 1980s, 45% have probably or certainly declined and 18% have probably or certainly increased. Several large colonies in the South Sandwich Islands, where conditions apparently remain favorable for Chinstrap penguins, cannot be assessed against a historical benchmark. Our population assessment provides a detailed baseline for quantifying future changes in Chinstrap penguin abundance, sheds new light on the environmental drivers of Chinstrap penguin population dynamics in Antarctica, and contributes to ongoing monitoring and conservation efforts at a time of climate change and concerns over declining krill abundance in the Southern Ocean.
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Identification of Circovirus Genome in a Chinstrap Penguin (Pygoscelis antarcticus) and Adélie Penguin (Pygoscelis adeliae) on the Antarctic Peninsula.
Viruses, 2020Co-Authors: Hila Levy, Steven R. Fiddaman, Anni Djurhuus, Caitlin Black, Simona Kraberger, Adrian Smith, Tom Hart, Arvind VarsaniAbstract:Circoviruses infect a variety of animal species and have small (~1.8–2.2 kb) circular single-stranded DNA genomes. Recently a penguin circovirus (PenCV) was identified associated with an Adelie Penguin (Pygoscelis adeliae) with feather disorder and in the cloacal swabs of three asymptomatic Adelie Penguins at Cape Crozier, Antarctica. A total of 75 cloacal swab samples obtained from adults and chicks of three species of penguin (genus: Pygoscelis) from seven Antarctic breeding colonies (South Shetland Islands and Western Antarctic Peninsula) in the 2015−2016 breeding season were screened for PenCV. We identified new variants of PenCV in one Adelie Penguin and one Chinstrap Penguin (Pygoscelis antarcticus) from Port Charcot, Booth Island, Western Antarctic Peninsula, a site home to all three species of Pygoscelid penguins. These two PenCV genomes (length of 1986 nucleotides) share > 99% genome-wide nucleotide identity with each other and share ~87% genome-wide nucleotide identity with the PenCV sequences described from Adelie Penguins at Cape Crozier ~4400 km away in East Antarctica. We did not find any evidence of recombination among PenCV sequences. This is the first report of PenCV in Chinstrap Penguins and the first detection outside of Ross Island, East Antarctica. Given the limited knowledge on Antarctic animal viral diversity, future samples from Antarctic wildlife should be screened for these and other viruses to determine the prevalence and potential impact of viral infections.
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seasonal consistency and individual variation in foraging strategies differ among and within Pygoscelis penguin species in the antarctic peninsula region
Marine Biology, 2017Co-Authors: Rachael Herman, Maria Virginia Petry, Tom Hart, Fernanda Caminha Leal Valls, Wayne Z Trivelpiece, Michael J PolitoAbstract:Past research during the breeding season in the Antarctic Peninsula region indicates that gentoo penguins (Pygoscelis papua) are generalist foragers whereas Adelie (P. adeliae) and chinstrap (P. antarcticus) penguins tend to specialize on Antarctic krill (Euphausia superba). However, little is known about the degree of temporal consistency in the diets and foraging habitats of these three species, particularly at the individual level. Such year-round and inter-annual dietary understanding is important to help interpret contrasting trends in their populations. We used carbon and nitrogen stable isotope analysis of blood and feathers to evaluate seasonal shifts in diet and individual foraging consistency within Pygoscelis penguin species breeding in the South Shetland Islands as well as among three geographically distinct gentoo penguin populations in the western Antarctic Peninsula and South Shetland Islands. We found that gentoo penguins exhibited a generalist foraging strategy with individual consistency, Adelie penguins exhibited an intermediate generalist foraging strategy with little individual consistency, and chinstrap penguins exhibited a specialized diet with little inter-individual variation. Our results also indicated that all three species have greater variation in foraging habitat use during the post-breeding season compared to the breeding season. Finally, we observed differences in the degree of seasonal shifts in population level diet and consistency in foraging strategies at the individual level across the three gentoo penguin populations examined. This suggests that Pygoscelis penguins can differ in diets and foraging habitat use not only at the population level among species, sites, and seasons, but also in the level of variation within populations, and in the degree of seasonal consistency among individuals.
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a reversal of fortunes climate change winners and losers in antarctic peninsula penguins
Scientific Reports, 2015Co-Authors: Gemma V Clucas, Ron Naveen, Michael J Dunn, Gareth J Dyke, Steven D Emslie, Michael J Polito, Oliver G Pybus, Alex Rogers, Tom HartAbstract:Climate change is a major threat to global biodiversity. Antarctic ecosystems are no exception. Investigating past species responses to climatic events can distinguish natural from anthropogenic impacts. Climate change produces ‘winners’, species that benefit from these events and ‘losers’, species that decline or become extinct. Using molecular techniques, we assess the demographic history and population structure of Pygoscelis penguins in the Scotia Arc related to climate warming after the Last Glacial Maximum (LGM). All three pygoscelid penguins responded positively to post-LGM warming by expanding from glacial refugia, with those breeding at higher latitudes expanding most. Northern (Pygoscelis papua papua) and Southern (Pygoscelis papua ellsworthii) gentoo sub-species likely diverged during the LGM. Comparing historical responses with the literature on current trends, we see Southern gentoo penguins are responding to current warming as they did during post-LGM warming, expanding their range southwards. Conversely, Adelie and chinstrap penguins are experiencing a ‘reversal of fortunes’ as they are now declining in the Antarctic Peninsula, the opposite of their response to post-LGM warming. This suggests current climate warming has decoupled historic population responses in the Antarctic Peninsula, favoring generalist gentoo penguins as climate change ‘winners’, while Adelie and chinstrap penguins have become climate change ‘losers’.
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a simplified method of determining the sex of Pygoscelis penguins using bill measurements
Marine ornithology, 2012Co-Authors: Michael J Polito, Tom Hart, Gemma V Clucas, Wayne Z TrivelpieceAbstract:We examined sexual dimorphism in bill size in adult Adelie Penguins Pygoscelis adeliae, adult Chinstrap Penguins P. antarctica and adult and juvenile Gentoo Penguins P. papua at King George Island, Antarctica, using a DNA-based molecular sexing technique. Bill length and depth were the most consistent dimorphic character examined, with measurements 5.4%–11.5% larger in males than in females, on average. Within breeding pairs sampled, male Chinstrap and Gentoo Penguins had consistently longer and deeper bills than their mates, although bill measurement overlapped between sexes at the population level. We used bill measurements to calculate species- and age-specific discriminant functions that correctly classified 83.2%–96.7% of the individuals in our study following cross-validation. The discriminant functions derived from this analysis provide a practical method of sex determination for all three Pygoscelis penguin species in the South Shetland Islands where they breed sympatrically. Posterior probability analysis can also be used to identify individuals that are likely to be incorrectly classified using discriminant function analysis, allowing DNA-based tests for gender to be reserved for targeted use. Furthermore, we report raw morphometric data to facilitate future analysis and discriminant function improvement
