The true sealtribeLobodontini, collectively known as the Antarctic seals or lobodontin seals, consist of four species of seals in four genera: the crabeater seal (Lobodon carcinophaga), the leopard seal (Hydrurga leptonyx), the Weddell seal (Leptonychotes weddelli), and the Ross seal (Ommatophoca rossii). All lobodontine seals have circumpolar distributions surrounding Antarctica. They include both the world's most abundant seal (the crabeater seal) and the only predominantly mammal-eating seal (the leopard seal). While the Weddell seal prefers the shore-fast ice, the other species live primarily on and around the off-shore pack ice. Thus, though they are collectively the most abundant group of seals in the world, the combination of remote range and inaccessible habitat make them among the least well studied of the world's seals.
Schematic of crabeater seal skull teeth, illustrating the unique krill-filtering lobes and cusps
The Lobondontini are thought to have diverged from the elephant seals (Mirounga) during the late Miocene in the Southern Ocean.[2][3] The leopard and crabeater seals possess lobes and cusps on their teeth useful for straining smaller prey items out of the water (the name "Lobodontini", meaning "lobe-toothed"). Nonetheless, they have diversified into specialized prey ecological niches, thereby illustrating the radiating sympatric speciation associated with colonization of a novel environment with multiple available niches. Thus, the crabeater seal, with the most specialized sieve-like dental features, is the only seal that feeds predominantly on Antarctic krill, while the leopard seal is the only seal which actively preys on other seals and penguins, while still retaining the ability to filter-feed on krill.[4]
Abundance
The lobodontin seals in aggregate are among the most successful of all marine mammal groups, collectively accounting for at least 50% of all seals on Earth and about 80% of the global biomass of pinnipeds.[5] The extremely high abundance of crabeater seals in particular, with possibly over 30,000,000 individuals, is a testament to the high productivity of the Southern Ocean, especially with respect to krill.[6] High numbers of seals may also be the indirect result of the wide-scale extermination of large baleen whales in the Antarctic due to commercial whaling in the 19th and 20th centuries, and the subsequent increase in krill densities.[7] Genetic evidence suggests that Weddell and crabeater seal populations may have increased in size during the Pleistocene.[8] None of the four species is currently thought to be declining in numbers.
^Wozencraft, W. C. (2005). "Order Carnivora". In Wilson, D. E.; Reeder, D. M. (eds.). Mammal Species of the World: A Taxonomic and Geographic Reference (3rd ed.). Johns Hopkins University Press. ISBN978-0-8018-8221-0. OCLC 62265494.
^Rule, James P.; Adams, Justin W.; Rovinsky, Douglass S.; Hocking, David P.; Evans, Alistair R.; Fitzgerald, Erich M. G. (November 2020). "A new large-bodied Pliocene seal with unusual cutting teeth". Royal Society Open Science. 7 (11): 201591. Bibcode:2020RSOS....701591R. doi:10.1098/rsos.201591. ISSN 2054-5703. PMC7735334. PMID 33391813.
^Rule, James P.; Adams, Justin W.; Marx, Felix G.; Evans, Alistair R.; Tennyson, Alan J. D.; Scofield, R. Paul; Fitzgerald, Erich M. G. (2020-11-11). "First monk seal from the Southern Hemisphere rewrites the evolutionary history of true seals". Proceedings of the Royal Society B. 287 (1938). doi:10.1098/rspb.2020.2318. PMC7735288. PMID 33171079.
^Boyd, I. (2009). "Antarctic Marine Mammals". In Perrin, W. F.; Würsig, B.; Thewissen, J. G. M. (eds.). Encyclopedia of Marine Mammals (2nd ed.). Academic Press. pp. 30–36. ISBN978-0-12-373553-9.
^Erickson, A. W., Siniff, D. B., Cline, D. R. and Hofman, R. J. (1971). Distributional ecology of Antarctic seals. In: G. Deacon (ed.), Symposium on Antarctic Ice and Water Masses, pp. 55-76. Sci. Comm. Antarct Res., Cambridge, UK.
^Mori, M.; Butterworth, D. (2006). "A first step towards modelling the krill-predator dynamics of the Antarctic ecosystem". CCAMLR Science. 13: 217–277.
^Curtis, Caitlin; Stewart, Brent S.; Karl, Stephen A. (2009-05-01). "Pleistocene population expansions of Antarctic seals". Molecular Ecology. 18 (10): 2112–2121. doi:10.1111/j.1365-294X.2009.04166.x. ISSN 1365-294X. PMID 19344354. S2CID 5323435.
January 26, 2023
lobodontini, true, seal, tribe, collectively, known, antarctic, seals, lobodontin, seals, consist, four, species, seals, four, genera, crabeater, seal, lobodon, carcinophaga, leopard, seal, hydrurga, leptonyx, weddell, seal, leptonychotes, weddelli, ross, seal. The true seal tribe Lobodontini collectively known as the Antarctic seals or lobodontin seals consist of four species of seals in four genera the crabeater seal Lobodon carcinophaga the leopard seal Hydrurga leptonyx the Weddell seal Leptonychotes weddelli and the Ross seal Ommatophoca rossii All lobodontine seals have circumpolar distributions surrounding Antarctica They include both the world s most abundant seal the crabeater seal and the only predominantly mammal eating seal the leopard seal While the Weddell seal prefers the shore fast ice the other species live primarily on and around the off shore pack ice Thus though they are collectively the most abundant group of seals in the world the combination of remote range and inaccessible habitat make them among the least well studied of the world s seals Lobodontine seals 1 Temporal range Late Miocene to recentCrabeater seal Lobodon carcinophagaScientific classificationKingdom AnimaliaPhylum ChordataClass MammaliaOrder CarnivoraClade PinnipediaFamily PhocidaeSubfamily MonachinaeTribe LobodontiniJ E Gray 1869GeneraHydrurga Leptonychotes Lobodon Ommatophoca Contents 1 Adaptations 2 Abundance 3 Genera 4 ReferencesAdaptations Edit Schematic of crabeater seal skull teeth illustrating the unique krill filtering lobes and cusps The Lobondontini are thought to have diverged from the elephant seals Mirounga during the late Miocene in the Southern Ocean 2 3 The leopard and crabeater seals possess lobes and cusps on their teeth useful for straining smaller prey items out of the water the name Lobodontini meaning lobe toothed Nonetheless they have diversified into specialized prey ecological niches thereby illustrating the radiating sympatric speciation associated with colonization of a novel environment with multiple available niches Thus the crabeater seal with the most specialized sieve like dental features is the only seal that feeds predominantly on Antarctic krill while the leopard seal is the only seal which actively preys on other seals and penguins while still retaining the ability to filter feed on krill 4 Abundance EditThe lobodontin seals in aggregate are among the most successful of all marine mammal groups collectively accounting for at least 50 of all seals on Earth and about 80 of the global biomass of pinnipeds 5 The extremely high abundance of crabeater seals in particular with possibly over 30 000 000 individuals is a testament to the high productivity of the Southern Ocean especially with respect to krill 6 High numbers of seals may also be the indirect result of the wide scale extermination of large baleen whales in the Antarctic due to commercial whaling in the 19th and 20th centuries and the subsequent increase in krill densities 7 Genetic evidence suggests that Weddell and crabeater seal populations may have increased in size during the Pleistocene 8 None of the four species is currently thought to be declining in numbers Genera EditImage Genus Species Lobodon Gray 1844 Crabeater seal Lobodon carcinophaga Hydrurga Gistel 1848 Leopard seal Hydrurga leptonyx Ommatophoca Gray 1844 Ross seal Ommatophoca rossii Leptonychotes Gill 1872 Weddell seal Leptonychotes weddellii References Edit Wozencraft W C 2005 Order Carnivora In Wilson D E Reeder D M eds Mammal Species of the World A Taxonomic and Geographic Reference 3rd ed Johns Hopkins University Press ISBN 978 0 8018 8221 0 OCLC 62265494 Rule James P Adams Justin W Rovinsky Douglass S Hocking David P Evans Alistair R Fitzgerald Erich M G November 2020 A new large bodied Pliocene seal with unusual cutting teeth Royal Society Open Science 7 11 201591 Bibcode 2020RSOS 701591R doi 10 1098 rsos 201591 ISSN 2054 5703 PMC 7735334 PMID 33391813 Rule James P Adams Justin W Marx Felix G Evans Alistair R Tennyson Alan J D Scofield R Paul Fitzgerald Erich M G 2020 11 11 First monk seal from the Southern Hemisphere rewrites the evolutionary history of true seals Proceedings of the Royal Society B 287 1938 doi 10 1098 rspb 2020 2318 PMC 7735288 PMID 33171079 Boyd I 2009 Antarctic Marine Mammals In Perrin W F Wursig B Thewissen J G M eds Encyclopedia of Marine Mammals 2nd ed Academic Press pp 30 36 ISBN 978 0 12 373553 9 Laws R M Seals In Laws R M ed Antarctic Ecology Vol 2 Academic Press London pp 621 675 Erickson A W Siniff D B Cline D R and Hofman R J 1971 Distributional ecology of Antarctic seals In G Deacon ed Symposium on Antarctic Ice and Water Masses pp 55 76 Sci Comm Antarct Res Cambridge UK Mori M Butterworth D 2006 A first step towards modelling the krill predator dynamics of the Antarctic ecosystem CCAMLR Science 13 217 277 Curtis Caitlin Stewart Brent S Karl Stephen A 2009 05 01 Pleistocene population expansions of Antarctic seals Molecular Ecology 18 10 2112 2121 doi 10 1111 j 1365 294X 2009 04166 x ISSN 1365 294X PMID 19344354 S2CID 5323435 Retrieved from https en wikipedia org w index php title Lobodontini amp oldid 1091901310, wikipedia, wiki, book, books, library,
