DOI: 10.1111/gbi.12205
Scopus记录号: 2-s2.0-84989244719
论文题名: Intraspecific variation in an Ediacaran skeletal metazoan: Namacalathus from the Nama Group, Namibia
作者: Penny A.M. ; Wood R.A. ; Zhuravlev A.Y. ; Curtis A. ; Bowyer F. ; Tostevin R.
刊名: Geobiology
ISSN: 1472-4677
EISSN: 1472-4669
出版年: 2017
卷: 15, 期: 1 起始页码: 81
结束页码: 93
语种: 英语
Scopus关键词: Ediacaran
; fossil record
; interspecific competition
; intraspecific variation
; landscape
; longevity
; metazoan
; microbial mat
; paleoecology
; redox conditions
; size distribution
; skeleton
; Namibia
; Metazoa
; Namacalathus
; animal
; aquatic species
; biodiversity
; classification
; fossil
; Namibia
; Animals
; Aquatic Organisms
; Biodiversity
; Fossils
; Namibia
Scopus学科分类: Earth and Planetary Sciences: General Earth and Planetary Sciences
; Environmental Science: General Environmental Science
; Agricultural and Biological Sciences: Ecology, Evolution, Behavior and Systematic
英文摘要: Namacalathus hermanastes is one of the oldest known skeletal metazoans, found in carbonate settings of the terminal Ediacaran (~550–541 million years ago [Ma]). The palaeoecology of this widespread, goblet-shaped, benthic organism is poorly constrained yet critical for understanding the dynamics of the earliest metazoan communities. Analysis of in situ assemblages from the Nama Group, Namibia (~548–541 Ma), shows that Namacalathus exhibited size variation in response to differing water depths, hydrodynamic conditions and substrate types. In low-energy, inner ramp environments, Namacalathus attains the largest average sizes but grew in transient, loosely aggregating, monospecific aggregations attached to microbial mats. In high-energy mid-ramp reefs, Namacalathus spatially segregated into different palaeoecological habitats with distinct size distributions. In outer ramp environments, individuals were small and formed patchy, dense, monospecific aggregations attached to thin microbial mats. Asexual budding is common in all settings. We infer that variations in size distribution in Namacalathus reflect differences in habitat heterogeneity and stability, including the longevity of mechanically stable substrates and oxic conditions. In the Nama Group, long-lived skeletal metazoan communities developed within topographically heterogeneous mid-ramp reefs, which provided diverse mechanically stable microbial substrates in persistently oxic waters, while inner and outer ramp communities were often ephemeral, developing during fleeting episodes of either oxia and/or substrate stability. We conclude that Namacalathus, which forms a component of these communities in the Nama Group, was a generalist that adapted to various palaeoecological habitats within a heterogeneous ecosystem landscape where favourable conditions persisted, and was also able to opportunistically colonise transiently hospitable environments. These early skeletal metazoans colonised previously unoccupied substrates in thrombolitic reefs and other microbial carbonate settings, and while they experienced relatively low levels of interspecific competition, they were nonetheless adapted to the diverse environments and highly dynamic redox conditions present in the terminal Ediacaran. © 2016 John Wiley & Sons Ltd Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/85084
Appears in Collections: 影响、适应和脆弱性
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作者单位: School of GeoSciences, Grant Institute, University of Edinburgh, Edinburgh, United Kingdom; Department of Biological Evolution, Faculty of Biology, Lomonosov Moscow State University, Moscow, Russian Federation; Geological Institute, Russian Academy of Sciences, Moscow, Russian Federation; Department of Earth Sciences, University College London, London, United Kingdom
Recommended Citation:
Penny A.M.,Wood R.A.,Zhuravlev A.Y.,et al. Intraspecific variation in an Ediacaran skeletal metazoan: Namacalathus from the Nama Group, Namibia[J]. Geobiology,2017-01-01,15(1)