Hostname: page-component-586b7cd67f-t8hqh Total loading time: 0 Render date: 2024-11-23T20:32:29.922Z Has data issue: false hasContentIssue false

Substrate affinities of higher taxa and the Ordovician Radiation

Published online by Cambridge University Press:  20 May 2016

Arnold I. Miller
Affiliation:
Department of Geology, Post Office Box 210013, University of Cincinnati, Cincinnati, Ohio 45221-0013. [email protected]
Sean R. Connolly
Affiliation:
Department of Geosciences, University of Arizona, Tucson, Arizona, 85721

Abstract

The Ordovician Radiation exhibited a global transition in dominance from the Cambrian evolutionary fauna (e.g., trilobites), to the Paleozoic and Modern faunas (e.g., articulate brachiopods and bivalve molluscs). Although its causes have yet to be determined definitively, the transition coincided with increased global tectonism. Erosion of source areas uplifted during orogenic activity increased the siliciclastic richness of marine substrates in many venues, and it has been hypothesized previously that higher taxa with affinities for siliciclastics diversified in association with these environmental changes, whereas higher taxa not exhibiting such affinities either failed to radiate or declined in diversity. Here, we provide an initial test of this substrate affinity hypothesis by evaluating the Ordovician affinities of trilobites and articulate brachiopods.

Our analyses—at the class level for both trilobites and articulate brachiopods, and at the order level for orthid and strophomenid brachiopods—were based on the affinities of constituent genera for siliciclastic, carbonate, and mixed siliciclastic/carbonate settings. Individual genus affinities are calculated with a database of genus occurrences encompassing nine Ordovician paleocontinents. Using these values, we developed a standardized relative affinity (SRA) metric to compare the propensities of higher taxa, and to assess changes in relative affinities of individual higher taxa from series to series.

A simple comparison of trilobites and articulate brachiopods for the Ordovician in aggregate does not appear to support the substrate affinity hypothesis: articulate brachiopods, which contributed increasingly to overall diversity through the period, exhibit an overall affinity for carbonates and an aversion to siliciclastics. However, a rather different view emerges when we consider the affinity trajectories of higher taxa through the period: articulate brachiopods exhibit a growing affinity for siliciclastics and a declining affinity for carbonates, whereas the opposite is the case among trilobites. Among constituent articulate brachiopod orders, the affinity trajectories of orthids and strophomenids mirror that of the class. Thus, the increasing dominance of articulate brachiopods in the Middle and Late Ordovician may have been linked to the affinity for siliciclastics of a diversifying subset of the group, but further investigation will be required to verify this claim.

Type
Articles
Copyright
Copyright © The Paleontological Society 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Literature Cited

Adrain, J. M.Fortey, R. A.Westrop, S. R. 1998. Post-Cambrian trilobite diversity and evolutionary faunas. Science 280: 19221925.CrossRefGoogle ScholarPubMed
Babin, C. 1993. Rôle des plates-formes gondwaniennes dans les diversifications des mollusques bivalves durant l'Ordivicien. Bulletin de la Société Géologique de France 164:141153.Google Scholar
Babin, C. 2000. Ordovician to Devonian diversification of the Bivalvia. American Malacological Bulletin 15:167178.Google Scholar
Connolly, S. R.Miller, A. I. 2002. Global Ordovician faunal transitions in the marine benthos: ultimate causes. Paleobiology 28 (in press).Google Scholar
Connolly, S. R.Miller, A. I. 2001a. Joint estimation of sampling and turnover rates from fossil databases: capture-mark-recapture methods revisited. Paleobiology 27:751767 (this volume).2.0.CO;2>CrossRefGoogle Scholar
Connolly, S. R.Miller, A. I. 2001b. Global Ordovician faunal transitions in the marine benthos: proximate causes. Paleobiology 27:779795 (this volume).2.0.CO;2>CrossRefGoogle Scholar
Foote, M. 1991. Morphological patterns of diversification: examples from trilobites. Palaeontology 34:461485.Google Scholar
Foote, M. 1993. Discordance and concordance between morphological and taxonomic diversity. Paleobiology 19:185204.CrossRefGoogle Scholar
Foote, M. 2000. Origination and extinction components of taxonomic diversity: Paleozoic and post-Paleozoic dynamics. Paleobiology 26:578605.Google Scholar
Khain, V. E.Seslavinsky, K. B. 1996. Historical geotectonics: Palaeozoic. Balkema, Rotterdam.Google Scholar
Kirschner, M.Gerhart, J. 1998. Evolvability. Proceedings of the National Academy of Sciences USA 95:84208427.CrossRefGoogle ScholarPubMed
Li, X.Droser, M. L. 1999. Lower and Middle Ordovician shell beds from the Basin and Range Province of the Western United States (California, Nevada, and Utah). Palaios 14:215233.Google Scholar
Miller, A. I. 1997a. Comparative diversification dynamics among palaeocontinents during the Ordovician Radiation. Géobios Mémoire Spécial 20:397406.Google Scholar
Miller, A. I. 1997b. Dissecting global diversity trends: examples from the Ordovician radiation. Annual Review of Ecology and Systematics 28:85104.Google Scholar
Miller, A. I. 1997c. A new look at age and area: the geographic and environmental expansion of genera during the Ordovician Radiation. Paleobiology 23:410419.Google Scholar
Miller, A. I.Foote, M. 1996. Calibrating the Ordovician radiation of marine life: implications for Phanerozoic diversity trends. Paleobiology 22:304309.Google Scholar
Miller, A. I.Mao, S. 1995. Association of orogenic activity with the Ordovician radiation of marine life. Geology 23:305308.Google Scholar
Miller, A. I.Mao, S. 1998. Scales of diversification and the Ordovician radiation. Pp. 288310in McKinney, M. L.Drake, J. A., eds. Biodiversity dynamics: turnover of populations, taxa, and communities. Columbia University Press, New York.Google Scholar
Patzkowsky, M. E.Holland, S. M. 1993. Biotic response to a Middle Ordovician paleoceanographic event in eastern North America. Geology 21:619622.Google Scholar
Patzkowsky, M. E.Holland, S. M. 1997. Patterns of turnover in Middle and Upper Ordovician brachiopods of the eastern United States: a test of coordinated stasis. Paleobiology 23:420443.Google Scholar
Patzkowsky, M. E.Holland, S. M. 1999. Biofacies replacement in a sequence stratigraphic framework: Middle and Upper Ordovician of the Nasville Dome, Tennessee, USA. Palaios 14:301323.Google Scholar
Raup, D. M. 1991. The future of analytical paleobiology. In Gilinsky, N. L.Signor, P. W., eds. Analytical paleobiology. Short Courses in Paleontology 14:207216. Paleontological Society, Knoxville, Tenn.Google Scholar
Sepkoski, J. J. Jr. 1979. A kinetic model of Phanerozoic taxonomic diversity II. Early Phanerozoic families and multiple equilibria. Paleobiology 5:222251.CrossRefGoogle Scholar
Sepkoski, J. J. Jr. 1981. A factor analytic description of the Phanerozoic marine fossil record. Paleobiology 7:3653.Google Scholar
Sepkoski, J. J. Jr. 1997. Biodiversity: past, present, and future. Journal of Paleontology 71:533539.Google Scholar
Sepkoski, J. J. Jr.Miller, A. I. 1985. Evolutionary faunas and the distribution of Paleozoic benthic communities in space and time. Pp. 153190in Valentine, J. W., ed. Phanerozoic diversity patterns: profiles in macroevolution. AAAS, Pacific Division and Princeton University Press, Princeton, N.J.Google Scholar
Sepkoski, J. J. Jr.Sheehan, P. M. 1983. Diversification, faunal change, and community replacement during the Ordovician radiations. Pp. 673717in Tevesz, M. J. S.McCall, P. L., eds. Biotic interactions in Recent and fossil benthic marine communities. Plenum, New York.Google Scholar
Westrop, S. R.Adrain, J. M. 1998. Trilobite alpha diversity and the reorganization of Ordovician benthic marine communities. Paleobiology 24:116.Google Scholar