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Size-frequency distributions along a latitudinal gradient in Middle Permian fusulinoideans.

Zhang Y, Payne JL - PLoS ONE (2012)

Bottom Line: We recovered the following results: keriothecal fusulinoideans are substantially larger than nonkeriothecal fusulinoideans; fusulinoideans from the equatorial zone are typically larger than those from the north and south transitional zones; neoschwagerinid specimens within a single species are generally larger in the equatorial zone than those in both transitional zones; and the nonkeriothecal fusulinoideans Staffellidae and Schubertellidae have smaller size in the north transitional zone.Temporal variation in atmospheric oxygen concentrations have been shown to account for temporal variation in fusulinoidean size during Carboniferous and Permian time, but oxygen availability appears unlikely to explain biogeographic variation in fusulinoidean sizes, because dissolved oxygen concentrations in seawater typically increase away from the equator due to declining seawater temperatures.Consequently, our findings highlight the fact that spatial gradients in organism size are not always controlled by the same factors that govern temporal trends within the same clade.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, CAS, Nanjing, Jiangsu, China. geozyc@yahoo.com

ABSTRACT
Geographic gradients in body size within and among living species are commonly used to identify controls on the long-term evolution of organism size. However, the persistence of these gradients over evolutionary time remains largely unknown because ancient biogeographic variation in organism size is poorly documented. Middle Permian fusulinoidean foraminifera are ideal for investigating the temporal persistence of geographic gradients in organism size because they were diverse and abundant along a broad range of paleo-latitudes during this interval (~275-260 million years ago). In this study, we determined the sizes of Middle Permian fusulinoidean fossils from three different paleo-latitudinal zones in order to examine the relationship between the size of foraminifers and regional environment. We recovered the following results: keriothecal fusulinoideans are substantially larger than nonkeriothecal fusulinoideans; fusulinoideans from the equatorial zone are typically larger than those from the north and south transitional zones; neoschwagerinid specimens within a single species are generally larger in the equatorial zone than those in both transitional zones; and the nonkeriothecal fusulinoideans Staffellidae and Schubertellidae have smaller size in the north transitional zone. Fusulinoidean foraminifers differ from most other marine taxa in exhibiting larger sizes closer to the equator, contrary to Bergmann's rule. Meridional variation in seasonality, water temperature, nutrient availability, and carbonate saturation level are all likely to have favored or enabled larger sizes in equatorial regions. Temporal variation in atmospheric oxygen concentrations have been shown to account for temporal variation in fusulinoidean size during Carboniferous and Permian time, but oxygen availability appears unlikely to explain biogeographic variation in fusulinoidean sizes, because dissolved oxygen concentrations in seawater typically increase away from the equator due to declining seawater temperatures. Consequently, our findings highlight the fact that spatial gradients in organism size are not always controlled by the same factors that govern temporal trends within the same clade.

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Middle Permian paleogeographic map showing three realms and blocks containing fusulinoideans in the analysis (base map modified after [68]).Abbreviations/key: N, north transitional zone; E, equatorial zone; S, south transitional zone; 1, Akiyoshi Terrane; 2, Altaid Belt; 3, Armenia; 4, Baoshan Block; 5, Carnic Alps; 6, Central Iran; 7, Changning-Menglian Belt; 8, Crimea; 9, Darvaz; 10, exotic Karakaya complex in Turkey; 11, Greece; 12, Hida Gaien Belt; 13, Indochina Block; 14, Iraq; 15, Israel; 16, Karakorum; 17, Kitakami Terrane; 18, Kunlun-Qadam Block; 19, Lhasa Block; 20, exotic blocks in New Zealand; 21, north Afghanistan; 22, north Caucasus; 23, north Pamir; 24, northern margin of North China Block; 25, Oman; 26, Qamdo Block; 27, Qiangtang Block; 28, Qinling Belt; 29, Salt Range; 30, Sanandaj-Sirjan zone of Iran; 31, Sibumasu Block; 32, Sicily; 33, Slovenia; 34, south Afghanistan; 35, South China; 36, south Pamir; 37, South Primorye; 38, Tengchong Block; 39, Tethys Himalaya; 40, Transcaucasia; 41, Tunisia; 42, Turkey.
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pone-0038603-g001: Middle Permian paleogeographic map showing three realms and blocks containing fusulinoideans in the analysis (base map modified after [68]).Abbreviations/key: N, north transitional zone; E, equatorial zone; S, south transitional zone; 1, Akiyoshi Terrane; 2, Altaid Belt; 3, Armenia; 4, Baoshan Block; 5, Carnic Alps; 6, Central Iran; 7, Changning-Menglian Belt; 8, Crimea; 9, Darvaz; 10, exotic Karakaya complex in Turkey; 11, Greece; 12, Hida Gaien Belt; 13, Indochina Block; 14, Iraq; 15, Israel; 16, Karakorum; 17, Kitakami Terrane; 18, Kunlun-Qadam Block; 19, Lhasa Block; 20, exotic blocks in New Zealand; 21, north Afghanistan; 22, north Caucasus; 23, north Pamir; 24, northern margin of North China Block; 25, Oman; 26, Qamdo Block; 27, Qiangtang Block; 28, Qinling Belt; 29, Salt Range; 30, Sanandaj-Sirjan zone of Iran; 31, Sibumasu Block; 32, Sicily; 33, Slovenia; 34, south Afghanistan; 35, South China; 36, south Pamir; 37, South Primorye; 38, Tengchong Block; 39, Tethys Himalaya; 40, Transcaucasia; 41, Tunisia; 42, Turkey.

Mentions: We compiled size data for Middle Permian fusulinoideans from 194 monographs illustrating Middle Permian fusulinoideans from the Tethyan region, together with one author's [Z.Y.] unpublished data from the south transitional zone (Fig. 1). The length and diameter of each fusulinoidean specimen was either compiled from tables or was measured from figures if no size data were provided explicitly in the monograph. Volumes were calculated by assuming that fusulinoideans are approximately three-dimensional ellipsoids: V = 4/3·π·r2·l where r represents the radius and l the half-length.


Size-frequency distributions along a latitudinal gradient in Middle Permian fusulinoideans.

Zhang Y, Payne JL - PLoS ONE (2012)

Middle Permian paleogeographic map showing three realms and blocks containing fusulinoideans in the analysis (base map modified after [68]).Abbreviations/key: N, north transitional zone; E, equatorial zone; S, south transitional zone; 1, Akiyoshi Terrane; 2, Altaid Belt; 3, Armenia; 4, Baoshan Block; 5, Carnic Alps; 6, Central Iran; 7, Changning-Menglian Belt; 8, Crimea; 9, Darvaz; 10, exotic Karakaya complex in Turkey; 11, Greece; 12, Hida Gaien Belt; 13, Indochina Block; 14, Iraq; 15, Israel; 16, Karakorum; 17, Kitakami Terrane; 18, Kunlun-Qadam Block; 19, Lhasa Block; 20, exotic blocks in New Zealand; 21, north Afghanistan; 22, north Caucasus; 23, north Pamir; 24, northern margin of North China Block; 25, Oman; 26, Qamdo Block; 27, Qiangtang Block; 28, Qinling Belt; 29, Salt Range; 30, Sanandaj-Sirjan zone of Iran; 31, Sibumasu Block; 32, Sicily; 33, Slovenia; 34, south Afghanistan; 35, South China; 36, south Pamir; 37, South Primorye; 38, Tengchong Block; 39, Tethys Himalaya; 40, Transcaucasia; 41, Tunisia; 42, Turkey.
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC3369838&req=5

pone-0038603-g001: Middle Permian paleogeographic map showing three realms and blocks containing fusulinoideans in the analysis (base map modified after [68]).Abbreviations/key: N, north transitional zone; E, equatorial zone; S, south transitional zone; 1, Akiyoshi Terrane; 2, Altaid Belt; 3, Armenia; 4, Baoshan Block; 5, Carnic Alps; 6, Central Iran; 7, Changning-Menglian Belt; 8, Crimea; 9, Darvaz; 10, exotic Karakaya complex in Turkey; 11, Greece; 12, Hida Gaien Belt; 13, Indochina Block; 14, Iraq; 15, Israel; 16, Karakorum; 17, Kitakami Terrane; 18, Kunlun-Qadam Block; 19, Lhasa Block; 20, exotic blocks in New Zealand; 21, north Afghanistan; 22, north Caucasus; 23, north Pamir; 24, northern margin of North China Block; 25, Oman; 26, Qamdo Block; 27, Qiangtang Block; 28, Qinling Belt; 29, Salt Range; 30, Sanandaj-Sirjan zone of Iran; 31, Sibumasu Block; 32, Sicily; 33, Slovenia; 34, south Afghanistan; 35, South China; 36, south Pamir; 37, South Primorye; 38, Tengchong Block; 39, Tethys Himalaya; 40, Transcaucasia; 41, Tunisia; 42, Turkey.
Mentions: We compiled size data for Middle Permian fusulinoideans from 194 monographs illustrating Middle Permian fusulinoideans from the Tethyan region, together with one author's [Z.Y.] unpublished data from the south transitional zone (Fig. 1). The length and diameter of each fusulinoidean specimen was either compiled from tables or was measured from figures if no size data were provided explicitly in the monograph. Volumes were calculated by assuming that fusulinoideans are approximately three-dimensional ellipsoids: V = 4/3·π·r2·l where r represents the radius and l the half-length.

Bottom Line: We recovered the following results: keriothecal fusulinoideans are substantially larger than nonkeriothecal fusulinoideans; fusulinoideans from the equatorial zone are typically larger than those from the north and south transitional zones; neoschwagerinid specimens within a single species are generally larger in the equatorial zone than those in both transitional zones; and the nonkeriothecal fusulinoideans Staffellidae and Schubertellidae have smaller size in the north transitional zone.Temporal variation in atmospheric oxygen concentrations have been shown to account for temporal variation in fusulinoidean size during Carboniferous and Permian time, but oxygen availability appears unlikely to explain biogeographic variation in fusulinoidean sizes, because dissolved oxygen concentrations in seawater typically increase away from the equator due to declining seawater temperatures.Consequently, our findings highlight the fact that spatial gradients in organism size are not always controlled by the same factors that govern temporal trends within the same clade.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, CAS, Nanjing, Jiangsu, China. geozyc@yahoo.com

ABSTRACT
Geographic gradients in body size within and among living species are commonly used to identify controls on the long-term evolution of organism size. However, the persistence of these gradients over evolutionary time remains largely unknown because ancient biogeographic variation in organism size is poorly documented. Middle Permian fusulinoidean foraminifera are ideal for investigating the temporal persistence of geographic gradients in organism size because they were diverse and abundant along a broad range of paleo-latitudes during this interval (~275-260 million years ago). In this study, we determined the sizes of Middle Permian fusulinoidean fossils from three different paleo-latitudinal zones in order to examine the relationship between the size of foraminifers and regional environment. We recovered the following results: keriothecal fusulinoideans are substantially larger than nonkeriothecal fusulinoideans; fusulinoideans from the equatorial zone are typically larger than those from the north and south transitional zones; neoschwagerinid specimens within a single species are generally larger in the equatorial zone than those in both transitional zones; and the nonkeriothecal fusulinoideans Staffellidae and Schubertellidae have smaller size in the north transitional zone. Fusulinoidean foraminifers differ from most other marine taxa in exhibiting larger sizes closer to the equator, contrary to Bergmann's rule. Meridional variation in seasonality, water temperature, nutrient availability, and carbonate saturation level are all likely to have favored or enabled larger sizes in equatorial regions. Temporal variation in atmospheric oxygen concentrations have been shown to account for temporal variation in fusulinoidean size during Carboniferous and Permian time, but oxygen availability appears unlikely to explain biogeographic variation in fusulinoidean sizes, because dissolved oxygen concentrations in seawater typically increase away from the equator due to declining seawater temperatures. Consequently, our findings highlight the fact that spatial gradients in organism size are not always controlled by the same factors that govern temporal trends within the same clade.

Show MeSH
Related in: MedlinePlus