The reproductive success of the Steller sea lion Eumetopias jubatus (Schreber, 1776) on Brat Chirpoev and Medny islands in 2001–2011

Permyakov, Peter A.; Ryazanov, Sergey D.; Трухин, А. М.; Mamaev, Evgeny; Burkanov, Vladimir N.

doi:10.1134/s1063074014060182

Cited by 6 publications

(5 citation statements)

References 6 publications

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“…In contrast, the heterozygosity estimate for E. jubatus is extremely low. We suggest that this fact is related to the nowadays population decline of E. jubatus, which began in the 1980s and continues to this day across its distribution range [20,21].…”

Section: Heterozygosity Of Extinct Dokdo Sea Lionmentioning

confidence: 87%

Dokdo sea lionZalophus japonicusgenome reveals its evolutionary trajectory before extinction

Kim,

Blazyte,

Choi

et al. 2024

Preprint

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BackgroundThe Dokdo sea lion (Zalophus japonicus), commonly referred to as Gangchi in Korea and known as the Japanese sea lion, was endemic to the Northwest Pacific coast before becoming extinct in the 1950s. Little is known about its origins, speciation compared to otherOtariidaespecies or how the rapid decline affected the species’ genetic diversity.ResultsTo raise the Dokdo sea lion from this relative obscurity, we sequenced DNA from 16Z. japonicus’ bone fragments, obtained from Dokdo and Ulleungdo islands in Korea. Our analysis establishesZ. japonicusas the earliest diverged species within its genus, significantly redefining its evolutionary relationship with the California (Z. californianus) and Galapagos (Z. wollebaeki) sea lions. This genome-scale analysis clarifies the phylogeny ofZ. japonicus, shedding light on its speciation and the evolutionary pathways that shaped its genetic diversity before its extinction. In addition, we discovered, population decline of theZ. japonicusstarted already 1,000 years ago, however,Z. japonicusgenome maintained a relatively high heterozygosity despite, nearing extinction.ConclusionsOur genome-scale analysis eliminated ambiguity inZ. japonicusphylogeny, and shed light on the evolutionary pathways underlying its speciation. This study highlights the importance of the genome-scale analysis for extinct species to understand their complex evolutionary histories and conservation status.

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Section: Heterozygosity Of Extinct Dokdo Sea Lionmentioning

confidence: 87%

Dokdo sea lionZalophus japonicusgenome reveals its evolutionary trajectory before extinction

Kim,

Blazyte,

Choi

et al. 2024

Preprint

View full text Add to dashboard Cite

show abstract

“…4). We suggest that this fact is related to the nowadays population decline of E. jubatus, which began in the 1980s and continues to this day across its distribution range [20,21].…”

Section: Heterozygosity Of Extinct Dokdo Sea Lionmentioning

confidence: 87%

Dokdo sea lion Zalophus japonicus genome reveals its evolutionary trajectory before extinction

Kim,

Blazyte,

Choi

et al. 2024

Preprint

View full text Add to dashboard Cite

Background The Dokdo sea lion (Zalophus japonicus), commonly referred to as Gangchi in Korea also known as the Japanese sea lion, was endemic to the Northwest Pacific coast before becoming extinct in the 1950s. Little is known about its origins and speciation compared to other Otariidae species or how the rapid decline affected the species’ genetic diversity. Results To raise the Dokdo sea lion from this relative obscurity, we sequenced DNA from 16 Z. japonicus’ bone fragments, obtained from Dokdo and Ulleungdo islands in Korea. Our genome-wide SNP-based analyses establish Z. japonicus as the earliest diverged species within its genus, significantly redefining its evolutionary relationship with the California (Z. californianus) and Galapagos (Z. wollebaeki) sea lions. Our research further elucidates the phylogeny of Z. japonicus, shedding light on the complexity of the genetic isolation process within its genus that was prompted by the geographic isolation of the three populations of Zalophus ancestral stock. Conversely, the genetic signature of Dokdo sea lion genome can be modeled as an evolutionary pathway involving gene flow from Otariidae species with shared range. In addition, we discovered, population decline of the Z. japonicus started already over 1,000 years ago, however, Z. japonicus genome maintained a relatively high heterozygosity despite nearing extinction. Conclusions Our genome-scale analysis has eliminated ambiguity in the phylogeny of Z. japonicus and shed light on the evolutionary pathways underlying its speciation and the genetic diversity before its extinction. Broadly, this study highlights the importance of genome-scale analysis for the extinct marine megafauna to elucidate the complexity of their gene flow and subsequent genetic diversities among extant species. Furthermore, this study offers retrospective genomic insights into the extinction process of a carnivorous marine mammal, information that could aid conservation efforts towards extant Otariidae species.

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“…Thirty-nine females and 38 males were age-assessed and seven females and males were of known ages. The specimens were marked at age 0 on their rookeries, and their exact ages were determined by counting backward from the date of cranium sampling (Burkanov et al 2011;Permyakov et al 2015). Thus, the ages within the entire sample ranged from 0 to 10 years for females and 0 to 11 years for males (Table 1).…”

Section: Specimensmentioning

confidence: 99%

Cranial ontogeny in Steller sea lions: Relationships between cranial morphology and suction feeding

Yuge,

Kobayashi,

Isono

et al. 2024

Preprint

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Suction feeding is a specific behavior in pinnipeds such as the Steller sea lion (Eumetopias jubatus), whereas the phylogenetically related brown bear (Ursus arctos) ingests by masticatory feeding. Because these feeding modes use different organs, the morphology and ontogeny of the cranial bones of these species may be related to differences in their feeding behavior. In this study, we performed multiple regression analyses to compare the ontogeny of Steller sea lion and brown bear cranial morphology by species and sex, using age, species, and the age × species interaction as explanatory variables and site measurements standardized by cranial length as response variables. The results showed that the palatine bone in both sexes widened with age in Steller sea lions compared to brown bears, whereas the width of the zygomatic arch was less developed in female Steller sea lions than in brown bears. This result may reflect the fact that the masticatory muscles are used less during suction feeding, whereas the tongue is used to perform force-intensive tasks. These results are consistent with previous studies on Carnivora and suggest that the development of the palatine bone and underdevelopment of the zygomatic arch represent characteristics of suction feeding.

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The reproductive success of the Steller sea lion Eumetopias jubatus (Schreber, 1776) on Brat Chirpoev and Medny islands in 2001–2011

Cited by 6 publications

References 6 publications

Dokdo sea lionZalophus japonicusgenome reveals its evolutionary trajectory before extinction

Dokdo sea lionZalophus japonicusgenome reveals its evolutionary trajectory before extinction

Dokdo sea lion Zalophus japonicus genome reveals its evolutionary trajectory before extinction

Cranial ontogeny in Steller sea lions: Relationships between cranial morphology and suction feeding

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