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Fig. 5 in Subcutaneous merocercoids of Clistobothrium sp. in two Cape fur seals (Arctocephalus pusillus pusillus)

Fig. 5. Suggested life cycle of Phyllobothriidea and the potential way of infection in the present cases.

Fig. 2 in Subcutaneous merocercoids of Clistobothrium sp. in two Cape fur seals (Arctocephalus pusillus pusillus)

Fig. 2. Histological section of subcutaneous adipose tissue of a 25- year–old, female fur seal (case No. 1) containing metacestode tapeworms with associated inflammation (box). The parasitic structures are characterized by a tegument (arrow) and centrally a parenchymatous matrix (asterisks) is present (A, bar = 1000 μm). Within the parenchymatous matrix of the parasite, numerous calcareous corpuscles stained with the "von Kossa" –method are present (B, bar = 100 μm). The parasite is surrounded by an inflammatory reaction composed of lymphocytes, plasma cells, macrophages and neutrophils (C, bar = 100 μm). A, C = hematoxylin and eosin.

Fig. 3 in Subcutaneous merocercoids of Clistobothrium sp. in two Cape fur seals (Arctocephalus pusillus pusillus)

Fig. 3. Light micrographs of isolated subcutaneous Clistobothrium sp. merocercoids of a fur seal (case No. 2). (A) merocercoid with invaginated scolex, (B) merocercoid with evaginated scolex on a long filament (cross), (C) scolex with terminal apical organ and four large bothridia (asterisk) each with anterior sucker (arrow), (D) bothridium with folded margin (asterisk) and large oval anterior sucker (arrow) with well–developed musculature.

Fig. 4 in Subcutaneous merocercoids of Clistobothrium sp. in two Cape fur seals (Arctocephalus pusillus pusillus)

Fig. 4. Phylogenetic trees of Clistobothrium sp. merocercoids from the Cape fur seal and related phyllobothriid species based on the 18S and 28S D2 rDNA regions using maximumlikelihood method. Nodal support is indicated by bootstrap values in percent; scale: number of substitutions per site; country and accession no. after the species name.

Fig. 1 in Subcutaneous merocercoids of Clistobothrium sp. in two Cape fur seals (Arctocephalus pusillus pusillus)

Fig. 1. Subcutaneous adipose tissue of a 27-year–old, female fur seal (case No. 2). Up to 1 cm in diameter large cavities (A, arrow) containing one or more parasites (B, arrow) as detected in the cross section. Bars = 1 cm.

opencc-by-4.0Dec 2019View details →

Fig. 3 in First report of pulmonary cysticercosis caused by Taenia crassiceps in a Cape fur seal (Arctocephalus pusillus)

Fig. 3. Alignment result for the partial sequence of the COX 1 gene (fur seal) with an exemplary T. crassiceps COX 1 gene sequence (accession no. KY321321.1), obtained from NCBI BLASTN tool. Homology was 100% (query: KY321321.1, sbject: herein obtained sequence).

Fig. 2 in Comparative analysis of the diet of Arctocephalus gazella (Pinnipedia), at two localities of the South Shetland Islands, with emphasis on the fish component

Fig. 2. Estimated standard length frequency distribution of Gymnoscopelus nicholsi (Gilbert, 1911), preyed on by Antarctic fur seals Arctocephalus gazella (Peters, 1875), at Stranger Point and Duthoit Point, South Shetland Islands, in February 2012.

Fig. 1 in Comparative analysis of the diet of Arctocephalus gazella (Pinnipedia), at two localities of the South Shetland Islands, with emphasis on the fish component

Fig. 1. The study area at South Shetland Islands: Stranger Point, King George Island/Isla 25 de Mayo and Duthoit Point, Nelson Island (modified from MALVÉ et al., 2014 and BRAUN et al., 2017).

Fig. 4 in Comparative analysis of the diet of Arctocephalus gazella (Pinnipedia), at two localities of the South Shetland Islands, with emphasis on the fish component

Fig. 4. Estimated standard length frequency distribution of Electrona antarctica (Gunther, 1878) preyed on by Arctocephalus gazella (Peters, 1875), at both sampling sites, Stranger Point and Duthoit Point, South Shetland Islands, in February 2012.

Fig. 3 in Comparative analysis of the diet of Arctocephalus gazella (Pinnipedia), at two localities of the South Shetland Islands, with emphasis on the fish component

Fig. 3. Estimated standard length frequency distribution of Pleuragramma antarctica (Boulenger, 1902) preyed on by Arctocephalus gazella (Peters, 1875), at both sampling sites, Stranger Point and Duthoit Point, South Shetland Islands, in February 2012.

publicJul 2024View details →

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Data from: Refinement of the Antarctic fur seal (Arctocephalus gazella) reference genome increases continuity and completeness

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Data from: Terrestrial spatial distribution and summer abundance of Antarctic fur seals (Arctocephalus gazella) near Palmer Station, Antarctica, from drone surveys

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publicJan 2025View details →

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Data from: Paleoclimatic changes resulted in range expansion and subsequent divergence in brown fur seals, Arctocephalus pusillus

Past climatic change as a driving force of marine diversification is still largely unclear, particularly for Southern Hemisphere species. Here, we present a case study using the brown fur seal, Arctocephalus pusillus, and assess the geographical structure and demographic history using mitochondrial and nuclear data. Results show the two previously defined subspecies (one from Australia and the other from Southern Africa) are phylogeographically distinct. Migration analyses based on nuclear data suggest the absence of migrants among the two genetically close assemblages. The demographic history of A. pusillus is characterized by a glacial population expansion (~18 Kya) in the Southern African taxon, which coincides with time estimates of population expansion of prey species of seals. Approximate Bayesian Calculations support an eastward dispersal event during the Last Glacial Maximum (LGM) when sea levels were lower, followed by a postglacial divergence event, ~ 13 Kya. The demographic history of the brown fur seal in the Southern Oceans provides support that recent paleoclimatic changes could have facilitated expansions in some marine species and that postglacial sea-level rise may have acted as a dispersal barrier for species mostly confined to continental shelves.

opencc-zeroAug 2022View details →

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Data from: Paleoclimatic changes resulted in range expansion and subsequent divergence in brown fur seals, Arctocephalus pusillus

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publicAug 2022View details →

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Data from: Behavioural thermoregulation in the Australian fur seal (Arctocephalus pusillus doriferus)

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publicSep 2025View details →

opencc-zeroDec 2010View details →

Data from: Gene discovery in the Antarctic fur seal (Arctocephalus gazella) skin transcriptome

Next-generation sequencing provides a powerful new approach for developing functional genomic tools for nonmodel species, helping to narrow the gap between studies of model organisms and those of natural populations. Consequently, massively parallel 454 sequencing was used to characterize a normalized cDNA library derived from skin biopsy samples of twelve Antarctic fur seal (Arctocephalus gazella) individuals. Over 412 Mb of sequence data were generated, comprising 1.4 million reads of average length 286 bp. De novo assembly using Newbler 2.3 yielded 156 contigs plus 22 869 isotigs, which in turn clustered into 18 576 isogroups. Almost half of the assembled transcript sequences showed significant similarity to the nr database, revealing a functionally diverse array of genes. Moreover, 97.9% of these mapped to the dog (Canis lupis familiaris) genome, with a strong positive relationship between the number of sequences locating to a given chromosome and the length of that chromosome in the dog indicating a broad genomic distribution. Average depth of coverage was also almost 20-fold, sufficient to detect several thousand putative microsatellite loci and single nucleotide polymorphisms. This study constitutes an important step towards developing genomic resources with which to address consequential questions in pinniped ecology and evolution. It also supports an earlier but smaller study showing that skin tissue can be a rich source of expressed genes, with important implications for studying the genomics not only of marine mammals, but also more generally of species that cannot be destructively sampled.

opencc-zeroDec 2009View details →

Data from: Exploring the mechanisms underlying a heterozygosity-fitness correlation for canine size in the Antarctic fur seal Arctocephalus gazella

Although heterozygosity-fitness correlations (HFCs) are widely reported in the literature, most studies use too few markers to allow the proximate mechanisms to be convincingly resolved. Two competing hypotheses have been proposed: the general effects hypothesis, in which marker heterozygosity correlates with genome-wide heterozygosity and hence the inbreeding coefficient f, and the local effects hypothesis, in which one or more of the markers by chance exhibit associative overdominance. To explore the relative contributions of general and local effects in a free-ranging marine mammal population, we revisited a strong HFC found using nine microsatellite loci for canine tooth size in 84 male Antarctic fur seals Arctocephalus gazella (Hoffman et al. 2010). Increasing the number of markers to 76, we find that heterozygosity is uncorrelated across markers, indicating that inbred individuals are rare or absent. Similarly, while the HFC based on overall heterozygosity is lost, stochastic simulations indicate that when an HFC is due to inbreeding depression, increasing marker number effectively invariably strengthens the HFC. Together these observations argue strongly that the original HFC was not due to inbreeding depression. In contrast, a subset of markers show individually significant effects, and these are non-randomly distributed across the marker panel, being preferentially associated with markers cloned from other species. Using BLAST searches, we were able to locate 94% of loci to unique locations in the dog genome, but the local genes are functionally diverse, and the majority cannot be linked directly to growth. Our results suggest that inbreeding depression contributes little if at all to the relationship between heterozygosity and tooth size, but that instead the primary mechanism involves associative overdominance. These findings contribute to a growing body of evidence suggesting that general effects are likely to be uncommon in natural populations

opencc-zeroDec 2015View details →

Data from: Low spatial genetic differentiation associated with rapid recolonization in the New Zealand fur seal Arctocephalus forsteri

Population declines resulting from anthropogenic activities are of major consequence for the long-term survival of species because the resulting loss of genetic diversity can lead to extinction via the effects of inbreeding depression, fixation of deleterious mutations, and loss of adaptive potential. Otariid pinnipeds have been exploited commercially to near extinction with some species showing higher demographic resilience and recolonization potential than others. The New Zealand fur seal (NZFS) was heavily impacted by commercial sealing between the late 18th and early 19th centuries, but has recolonized its former range in southern Australia. The species has also recolonized its former range in New Zealand, yet little is known about the pattern of recolonization. Here, we first used 11 microsatellite markers (n = 383) to investigate the contemporary population structure and dispersal patterns in the NZFS (Arctocephalus forsteri). Secondly, we model postsealing recolonization with 1 additional mtDNA cytochrome b (n = 261) marker. Our data identified 3 genetic clusters: an Australian, a subantarctic, and a New Zealand one, with a weak and probably transient subdivision within the latter cluster. Demographic history scenarios supported a recolonization of the New Zealand coastline from remote west coast colonies, which is consistent with contemporary gene flow and with the species' high resilience. The present data suggest the management of distinct genetic units in the North and South of New Zealand along a genetic gradient. Assignment of individuals to their colony of origin was limited (32%) with the present data indicating the current microsatellite markers are unlikely sufficient to assign fisheries bycatch of NZFSs to colonies.