TY - JOUR
T1 - Quantitative paleoecology of marine faunas in the lower Hamilton Group (Middle Devonian, central New York)
T2 - Significance for probing models of long-term community stability
AU - Newton, Cathryn R.
AU - Newman, Willis B.
AU - Brower, James C.
N1 - Funding Information:
Brower and Newton dedicate this paper to the honor and memory of John M. Dennison, M.S. advisor to Cathryn Newton and colleague of James Brower, and Willis B. Newman, our joint doctoral student, much respected and beloved, who conducted this fieldwork and analyses but did not complete the dissertation. Acknowledgment is made to the donors of the Petroleum Research Fund of the American Chemical Society for support of this research program. We also gratefully acknowledge a New York State Honorarium to W.B. Newman and ongoing research support to C.R. Newton from the Vice Chancellor and Provost of Academic Affairs at Syracuse University. Thanks are due to G.C. Baird of the State University of New York at Fredonia, C.E. Brett of the University of Cincinnati, T.X. Grasso of Monroe Community College, L.C. Ivany of Syracuse University, D. and R.M. Linsley of Colgate University, H.B. Rollins of the University of Pittsburgh, and B. Selleck of Colgate University for assistance in the field and for helpful discussions and scientific friendship over many years. Cathryn Newton offers deep and lasting gratitude to Jim Brower, Bob Linsley, and Bud Rollins for becoming tremendous mentors who showed her how to invest in others. John Harper and an anonymous reviewer suggested slight revisions that markedly improved the figures and paleontological and stratigraphic descriptions; K. Lee Avary further lent wisdom and knowledge to the revisions process - and friendship always. CRN also thanks her students, from whom she learned much. Special thanks go to G.K. Wissink, J.R. Corbett, R. Fein, R. Hennigan, S.N. Hill, M.S. Monmonier, and A. Stützle of Syracuse University, as well as the GSA Books editorial staff, who lent expertise crucial to the completion of this research.
Funding Information:
Acknowledgment is made to the donors of the Petroleum Research Fund of the American Chemical Society for support of this research program. We also gratefully acknowledge a New York State Honorarium to W.B. Newman and ongoing research support to C.R. Newton from the Vice Chancellor and Provost of Academic Affairs at Syracuse University. Thanks are due to G.C. Baird of the State University of New York at Fredo-nia, C.E. Brett of the University of Cincinnati, T.X. Grasso of Monroe Community College, L.C. Ivany of Syracuse University, D. and R.M. Linsley of Colgate University, H.B. Rollins of the University of Pittsburgh, and B. Selleck of Colgate University for assistance in the field and for helpful discussions and scientific friendship over many years. Cathryn Newton offers deep and lasting gratitude to Jim Brower, Bob Linsley, and Bud Rollins for becoming tremendous mentors who showed her how to invest in others. John Harper and an anonymous reviewer suggested slight revisions that markedly improved the figures and paleontological and stratigraphic descriptions; K. Lee Avary further lent wisdom and knowledge to the revisions process—and friendship always. CRN also thanks her students, from whom she learned much. Special thanks go to G.K. Wis- sink, J.R. Corbett, R. Fein, R. Hennigan, S.N. Hill, M.S. Mon-monier, and A. Stützle of Syracuse University, as well as the GSA Books editorial staff, who lent expertise crucial to the completion of this research.
Publisher Copyright:
© 2020 The Geological Society of America. All rights reserved.
PY - 2020/8/12
Y1 - 2020/8/12
N2 - Beautifully fossiliferous strata in the Hamilton Group (Middle Devonian, central New York) constitute a rich "ecological archive"sufficient to probe and test foundational concepts in paleontology. The evident community stability of Hamilton faunas over 4-6 m.y. - including two proposed mechanisms for coordinated stasis - has ignited controversy. Resolving community structure and both taxonomic and ecological temporal persistence within the Hamilton Group thus becomes critical to testing whether these Hamilton communities are stable and whether they are ecologically "locked."Toward this end, we conducted multivariate analyses (cluster and correspondence analysis) of marine faunas in 81 large samples (~300 specimens each) in shallowing-upward sequences of the Cardiff and Pecksport Members (Marcellus Subgroup, Oatka Creek Formation) of the Hamilton Group. Eight statistically and ecologically distinctive benthic communities characterize the vertical gradient, from depauperate, deeper-water dark shales below to species-rich shelf siltstones above. These communities correlate strongly with grain size, bioturbation intensity, bedding thickness, density of fossils, and faunal and ecological diversity. Species richness varies inversely with weight percent organic matter. We characterized taxonomic distributions using multivariate statistics; these statistical analyses were based on percentages of 50 taxa. In order of decreasing depth, the communities are: Cephalopod-Pterochaenia, Pterochaenia- Eumetabolotoechia, Eumetabolotoechia, Emanuella, Eumetabolotoechia-Ambocoelia, Arcuaminetes-Eumetabolotoechia, Arcuaminetes- Ambocoelia, and Mucrospirifer- Ambocoelia. The Cephalopod-Pterochaenia community represents a mixed benthicpelagic fauna associated with the deepest and finest-grained facies. The Pterochaenia-Eumetabolotoechia, Eumetabolotoechia, and Emanuella communities have low to moderate species richness and are dominated by epifaunal, active suspension feeders, especially the small epibyssate bivalve Pterochaenia fragilis, and the pedunculate brachiopods Eumetabolotoechia multicostata and Emanuella subumbona. The Pterochaenia-Eumetabolotoechia community is an opportunistic fauna that developed when the substrate first became favorable for colonization by benthic organisms. To a lesser extent, this probably also holds true for the Eumetabolotoechia assemblage. Communities near the top of the shallowing-upward cycle - Eumetabolotoechia- Ambocoelia, Arcuaminetes- Eumetabolotoechia, Arcuaminetes-Ambocoelia, and Mucrospirifer-Ambocoelia - have higher taxonomic and ecological heterogeneity, with a more diverse array of trophic and locomotory groups than their counterparts in the finer-grained, and inferred deeper, facies. Cluster significance tests applied to all pairs of communities known from adequate numbers of samples demonstrated that the communities are statistically valid and distinctive. Multivariate means of all communities were significantly different; furthermore, most pairs of communities were drawn from populations that showed no overlap in terms of rectangular distributions. The community sequence and an ordination derived from the first two axes of the correspondence analysis provided relative depth curves. Our communities, with two exceptions, do not have clear counterparts among upper Hamilton Group faunas. The ecological locking model proposed to explain the stability of Hamilton faunas is not supported by our quantitative tests to date.
AB - Beautifully fossiliferous strata in the Hamilton Group (Middle Devonian, central New York) constitute a rich "ecological archive"sufficient to probe and test foundational concepts in paleontology. The evident community stability of Hamilton faunas over 4-6 m.y. - including two proposed mechanisms for coordinated stasis - has ignited controversy. Resolving community structure and both taxonomic and ecological temporal persistence within the Hamilton Group thus becomes critical to testing whether these Hamilton communities are stable and whether they are ecologically "locked."Toward this end, we conducted multivariate analyses (cluster and correspondence analysis) of marine faunas in 81 large samples (~300 specimens each) in shallowing-upward sequences of the Cardiff and Pecksport Members (Marcellus Subgroup, Oatka Creek Formation) of the Hamilton Group. Eight statistically and ecologically distinctive benthic communities characterize the vertical gradient, from depauperate, deeper-water dark shales below to species-rich shelf siltstones above. These communities correlate strongly with grain size, bioturbation intensity, bedding thickness, density of fossils, and faunal and ecological diversity. Species richness varies inversely with weight percent organic matter. We characterized taxonomic distributions using multivariate statistics; these statistical analyses were based on percentages of 50 taxa. In order of decreasing depth, the communities are: Cephalopod-Pterochaenia, Pterochaenia- Eumetabolotoechia, Eumetabolotoechia, Emanuella, Eumetabolotoechia-Ambocoelia, Arcuaminetes-Eumetabolotoechia, Arcuaminetes- Ambocoelia, and Mucrospirifer- Ambocoelia. The Cephalopod-Pterochaenia community represents a mixed benthicpelagic fauna associated with the deepest and finest-grained facies. The Pterochaenia-Eumetabolotoechia, Eumetabolotoechia, and Emanuella communities have low to moderate species richness and are dominated by epifaunal, active suspension feeders, especially the small epibyssate bivalve Pterochaenia fragilis, and the pedunculate brachiopods Eumetabolotoechia multicostata and Emanuella subumbona. The Pterochaenia-Eumetabolotoechia community is an opportunistic fauna that developed when the substrate first became favorable for colonization by benthic organisms. To a lesser extent, this probably also holds true for the Eumetabolotoechia assemblage. Communities near the top of the shallowing-upward cycle - Eumetabolotoechia- Ambocoelia, Arcuaminetes- Eumetabolotoechia, Arcuaminetes-Ambocoelia, and Mucrospirifer-Ambocoelia - have higher taxonomic and ecological heterogeneity, with a more diverse array of trophic and locomotory groups than their counterparts in the finer-grained, and inferred deeper, facies. Cluster significance tests applied to all pairs of communities known from adequate numbers of samples demonstrated that the communities are statistically valid and distinctive. Multivariate means of all communities were significantly different; furthermore, most pairs of communities were drawn from populations that showed no overlap in terms of rectangular distributions. The community sequence and an ordination derived from the first two axes of the correspondence analysis provided relative depth curves. Our communities, with two exceptions, do not have clear counterparts among upper Hamilton Group faunas. The ecological locking model proposed to explain the stability of Hamilton faunas is not supported by our quantitative tests to date.
UR - http://www.scopus.com/inward/record.url?scp=85096795873&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85096795873&partnerID=8YFLogxK
U2 - 10.1130/2020.2545(09)
DO - 10.1130/2020.2545(09)
M3 - Article
AN - SCOPUS:85096795873
VL - 545
SP - 161
EP - 195
JO - Special Paper of the Geological Society of America
JF - Special Paper of the Geological Society of America
SN - 0072-1077
ER -