Associate Professor
McClain lab website
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Education · Research Interests · Current Projects · Research Group · Selected Publications


  • Ph.D., 2003, Environmental Biology
    University of Massachusetts, Boston
  • B.A., 1997, Biology
    Hendrix College


  • Deep-sea biodiversity and ecology
  • Energetics and metabolism
  • Body size evolution and ecology
  • Invertebrate zoology
  • Climate change impacts on marine invertebrate communities


  • Evolution of metabolism and scaling in marine invertebrates
  • Evolution and ecology of body size in deep-sea invertebrates
  • Processes underpinning diversity-energy relationships
  • Biodiversity of deep-sea woodfall communities
  • Changes in marine community energy usage through time


  • Clifton Nunnally, Research Associate
    • Ph.D., 2012, Oceanography
      Texas A&M University
    • M.S., 2003, Oceanography
      Texas A&M University
    • B.S., 1998, Biology
      Abilene Christian University
  • Chase Landry, Undergraduate Research Assistant


  • J.C. Uyeda, M.W. Pennell, E.T. Miller, R. Maia, and C.R. McClain (2017) The Evolution of Energetic Scaling across the Vertebrate Tree of Life.
    The American Naturalist 190 (2), 000-000
  • C.R. McClain (2017) Practices and promises of Facebook for science outreach: Becoming a “Nerd of Trust”. PLoS biology 15 (6), e2002020
  • T.J. Webb, J.P. Barry, and C.R. McClain (2016) Abundance‐occupancy relationships in deep-sea wood fall communities. Ecography, Online early.
  • Stuart, C.T.,  S. Brault, G.T. Rowe, C.‐L. Wei, M. Wagstaff, C.R. McClain, M.A. Rex (2016) Nestedness and species replacement along bathymetric gradients in the deep sea reflect productivity: a test with polychaete assemblages in the oligotrophic north‐west Gulf of Mexico. Journal of Biogeography. Online early.
  • Smith, F.A., J.L. Payne, M. Balk, S. Finnegan, N.A. Heim, M. Kowalewski, S.K. Lyons, C.R. McClain, D.W. McShea, P.M. Novack-Gottshall, P.A. Spaeth Anich and S.C. Wang (2016) Body size evolution across the Geozoic. Annual Review of Earth and Planetary Sciences. 44:523–53
  • McClain, C.R.,P. Barry, D. Eernisse, T. Horton, J. Judge, K. Kakui, C. Mah, and A. Warén (2016) Multiple processes generate productivity-diversity relationships in experimental wood-fall communities. Ecology 97: 885–898
  • Nunn, C.L., S.C. Alberts, R. McClain, S. Meshnick, T.J. Vison, B.M. Weigmann, A.G. Rodrigo (2015) Linking Evolution, Ecology, and Health: TriCEM. Bioscience, 8;748-749
  • McClain, C.R. and M.A. Rex (2015) Toward a conceptual understanding of beta-diversity in the deep-sea benthos. Annual Review of Ecology and Systematics 46:623-642
  • Orzechowski, E., R. Lockwood, J. Byrnes, S. Anderson, S. Finnegan, P. Harnik, Z.V. Finkel, D. Lindberg, L. Liow, H. Lotze, R. McClain, J. McGuire, A. O’Dea, J. Pandolfi, C. Simpson, and D. Tittensor (2015) Marine extinction risk shaped by trait-environment interactions over 500 million years. Global Change Biology, 10:3595–3607
  • Finnegan, S., S.C. Anderson, P.G. Harnik, C. Simpson, D.P. Tittensor, J.E. Byrnes, Z.V. Finkel, D.R. Lindberg, L.H. Liow, R. Lockwood, H. Lotze, R. McClain, J.L. McGurie, A. O’Dean, and J.M. Pandolfi (2015) Paleontological baselines for evaluating extinction risk in the modern oceans. Science 348:567-570
  • McClain, C.R. and T. Schlacher (2015) On some hypotheses of diversity of animal life at great depths on the seafloor. Marine Ecology online early
    Bik, H.M., A.D.M. Dove, M.C. Goldstein, R. Helm, R. MacPherson, K. Martini, A. Warneke, R. McClain(2015) Ten simple rules for effective online outreach. PLOS Computational Biology 11:e1003906
  • McClain, R., M.A. Balk, M.C. Benfield, T.A. Branch, C. Chen, J. Cosgrove, A. Dove, R.R. Helm, F.G.E. Hochberg, L.C. Gaskins, F.B. Lee, S.E. McMurray, C. Schanche, S.N. Stone, and A.D. Thaler (2015) Sizing ocean giants: patterns of intraspecific size variation in marine megafauna. Peer J, 2:e715
  • Martin, L.J., R.R. Dunn, R. Adams, A. Bateman, H.M. Bik, J. Hawks, S. Hird, D. Hughes, S. Kembel, K. Kinney, S.-O. Kolokotronis, C. Levy, R. McClain, J.F. Meadow, R. Medina, G. Mhuireach, C. Moreau, J. Munshi-South, C. Palmer, L. Popova, C. Schal, M. Taubel, M. Trautwein, J. Ugalde, (2015) Evolution of the indoor biome Trends in Ecology and Evolution 30:223-232
  • McClain C.R. and L. Lundsten (2015) Assemblage structure is related to slope and depth on a deep offshore Pacific seamount chain. Marine Ecology 36:210-220
  • McClain, C.R. and L. Neeley (2015) A critical evaluation of science outreach via social media: its role and impact on scientists. Faculty of 1000 Research 3:300
  • McClain, C.R., R. Filler, and J.R. Auld (2014) Does energy availability predicts diversity in gastropod reproductive strategies? Proceedings of the Royal Society, B 281:20140400
  • McClain, C.R. and J. Barry (2014) Beta-diversity on deep-sea wood falls reflects gradients in energy availability. Biology Letters 10:20140129
  • Payne, J., N. Heim, M. Knope, R. McClain (2014) Metabolic dominance of bivalves predates brachiopod diversity decline by 200 million years. Proceedings of the Royal Society, B 281:20133122
  • Brault, S., C.T. Stuart, M.C. Wagstaff, R. McClain, J.A. Allen, M.A. Rex (2013) Contrasting patterns of α- and β-diversity in deep-sea bivalves of the eastern and western North Atlantic. Deep-Sea Research II 92:157-164
  • Rodrigo A., S. Alberts, K. Cranston, J. Kingsolver, H. Lapp, R. McClain, R. Smith, T. Vision, J. Weintraub, and B. Weigmann(2013) Science Incubators: Synthesis Centers and Their Role in the Research Ecosystem. PLoS Biology 11: e1001468
  • McClain, C.R., P.A.P. Durst, A.G. Boyer, and C.D. Francis (2013) Unraveling the determinants of insular body size shifts. Biology Letters 9:1-3
  • Payne, J.L., F.A. Smith, M. Kowalewski, R.A. Krause, A.G. Boyer, R. McClain, S. Finnegan, P.M. Novack-Gottshall, and L. Sheble (2012) A lack of attribution: closing the citation gap through a reform of citation and indexing practices. Taxon. Online early
  • Thaler, A.D., K.A. Zelnio, A. Freitag, R. MacPherson, D. Shiffman, H. Bik, M.C. Goldstein, and R. McClain (2012). Digital Environmentalism: Tools and strategies for the evolving online ecosystem. In D. Gallagher (ed.) Environmental Leadership: A Reference Handbook.SAGE Reference
  • Harnik, P.G., H.K. Lotze, S.C. Anderson, Z.V. Finkel, S. Finnegan, D.R. Lindberg, L.H. Liow, R. Lockwood, R. McClain, J.L. McGuire, A. O’Dea, J.M. Pandolfi, C. Simpson, and D.P. Tittensor (2012) Extinctions in ancient and modern seas. Trends in Ecology and Evolution. 27:608-617
  • McClain, C.R., A.P. Allen, D.P. Tittensor, and M.A. Rex (2012) The Energetics of Life on the Deep Seafloor. Proceedings of the National Academy of Science, U.S.A. 38:15366-15371
  • McClain, C.R., P. Unmack, J. Jackson-Ricketts, and T. Gullet (2012). Increased Energy Promotes Size-Based Niche Availability in Marine Mollusks. Evolution 66:2204-2215
  • McClain, C.R., J.C. Stegen, and A.H. Hurlbert (2012) Dispersal, Niche Dynamics, and Oceanic Patterns in Beta-Diversity in Deep-Sea Bivalves. Proceeding of the Royal Society, B 22:1993-2002
  • Kowalewski, M., J.L. Payne, F.A. Smith, S.C. Wang, D.W. McShea, S. Xiao, P.M. Novack-Gottshall, R. McClain, R.A. Krause, A.G. Boyer, S. Finnegan, S.K. Lyons, J.A. Stempien, J. Alroy, and P.A. Spaeth (2011) The Geozoic Supereon. Paleos 26:251-255
  • Tittensor, D.P., M.A. Rex, C.T. Stuart, R. McClain, and C.R. Smith (2011) Species-energy relationships in deep-sea mollusks, Biology Letters, 7:718-722
  • McClain, C.R., J.Nekola, L.Kuhnz, and J. Barry (2011) Local-scale faunal turnover on the deep Pacific floor. Marine Ecology Progress Series, 442:193-200
  • Finnegan, S., C.R. McClain, M.A. Kosnik, and J.L. Payne (2011) Escargot through time: an energetic comparison of marine gastropod assemblages before and after the Mesozoic Marine Revolution. Paleobiology, 37:252-269
  • Payne, J.L., C.R. McClain, A.G. Boyer, J.H. Brown, S. Finnegan, M. Kowalewski, R.A. Krause Jr., S.K. Lyons, D.W. McShea, P.M. Novack-Gottshall, F.A. Smith, J.A. Stempien, and S.C. Wang (2011) The evolutionary consequences of oxygenic photosynthesis: a body size perspective. Photosynthesis Research, 107:37-57
  • Rex, M.A., C.T. Stuart, R.J. Etter, and R. McClain (2010) Biogeography of the deep-sea gastropod Oocorys sulcata Fischer 1884. Journal of Conchology 40: 287-290
  • McClain, C.R. and S. Hardy (2010) The dynamics of biogeographic ranges in the deep sea. Proceeding of the Royal Society, B, 277:3533-3546
  • McClain, C.R., L. Lundsten, J. Barry, and A. DeVogelaere (2010) Assemblage structure, but not diversity or density, change with depth on a northeast Pacific seamount. Marine Ecology, 31:1-12
  • McClain, C.R. and Barry, J.P (2010) Habitat heterogeneity, biogenic disturbance, and resource availability work in concert to regulate biodiversity in deep submarine canyons. Ecology, 91:964-976
  • McClain, C.R.,A. Rex, and R.J. Etter. (2009) Macroecological Patterns in the Deep Sea. In Marine Marcoecology. Eds. K. Roy and J. Whitman. University of Chicago Press
  • Lundsten, L., R. McClain, J.P. Barry, G.M. Caillet, D.A. Clague, A. DeVogelaere, and J.B. Geller (2009) Ichthyofauna on three seamounts off southern and central California. Marine Ecology Progress Series, 398:223-232
  • McClain, C.R. and A.G. Boyer (2009) Biodiversity and body size are linked across metazoans. Proceedings of Royal Society B: Biological Sciences, 276: 2209-2215 [Highlighted by Faculty of 1000]
  • McClain, C.R., L. Lundsten, M. Ream, J. Barry, and A. DeVogelaere (2009) Endemicity, Biogeography, Composition, and Community Structure On a Northeast Pacific Seamount. PLoS One, 4:e4141
  • Payne, J.L., A.G. Boyer, J.H. Brown, S. Finnegan, M. Kowalewski, R.A. Krause Jr., S.K. Lyons, R. McClain, D.W. McShea, P.M. Novack-Gottshall, F.A. Smith, J.A. Stempien, and S.C. Wang (2009) Two-phase increase in the maximum size of life over 3.5 billion years reflects biological innovation and environmental opportunity. Proceedings of the National Academy of Science, U.S.A.,1:24-27 [Highlighted by Faculty of 1000]
  • McClain, C.R. and J.C. Nekola (2008) The role of local-scale process on terrestrial and deep-sea gastropod body size distributions across multiple scales. Evolutionary Ecology Research, 10:129-146
  • McClain, C.R. (2007). Guest Editorial: Seamounts: Identity Crisis or Split Personality? Journal of Biogeography, 34:2001-2008
  • Johnson, N.A., M.A. Rex, J.W. Campbell, R. McClain, T.S. Moore, and M.D. Dowell (2007) The relationship between the standing stock of deep-sea macrobenthos and surface production in the western North Atlantic. Deep-Sea Research, 54:1350-1360
  • McClain, C.R., E.P. White, and A.H. Hurlbert (2007) Challenges in the application of geometric constraint models. Global Ecology and Biogeography, 16:257-264
  • Rex, M.A., R.J. Etter, J.S. Morris, J. Crouse, R. McClain, N.A. Johnson, C.T. Stuart, R. Thies, R. Avery (2006) Global bathymetric patterns of standing stock and body size in the deep-sea benthos. Marine Ecology Progress Series, 317:1-8 [featured article]
  • McClain, C.R. and J. Crouse (2006) The influence of ecological role on bathymetric patterns of deep-sea species: size clines in parasitic gastropods. Marine Ecology Progress Series, 320:161-167
  • McClain, C.R., A. Boyer, G. Rosenberg (2006) The island rule and the evolution of body size in the deep sea. Journal of Biogeography, 33:1578-1584 [featured article]
  • McClain, C.R., (2005) Bathymetric patterns of morphological disparity in deep-sea gastropods from the western North Atlantic Basin. Evolution, 59:1492-1499
  • McClain, C.R., M.A. Rex, and R. Jabbour. (2005) Deconstructing bathymetric patterns of body size in deep-sea gastropods. Marine Ecology Progress Series, 297:181-187
  • Rex, M.A., R. McClain, N.A. Johnson, R.J. Etter, J.A. Allen, P. Bouchet, A. Warén (2005) A source-sink hypothesis for abyssal biodiversity. American Naturalist, 165:163-178 [Am. Nat. Highlight Paper of 2005]
  • McClain, C.R., and Etter, R.J. (2005) Mid-domain models as predictors of species diversity patterns: a case study using bathymetric diversity gradients in the deep sea. Oikos, 109:555-566
  • McClain, C.R. (2004) Connecting species richness, abundance, and body size in deep-sea gastropods. Global Ecology and Biogeography, 13: 327-334
  • McClain, C.R., M.A. Rex, and N. Johnson (2004) Morphological disparity as a biodiversity metric in lower bathyal and abyssal gastropod assemblages. Evolution, 58:338-348
  • Linse, K., M. Schrödl, R. McClain, and L. Allcock (2003) Mollusca in the Antarctic deep sea-preliminary notes on their taxonomy, biogeography, and diversity. Reports on Polar and Marine Research (ANDEEP I & II: Antarctic benthic deep-sea biodiversity). 470:95-101
  • McClain, C.R., M. Fougerolle, M.A. Rex, and J. Welch. (2001) MOCNESS estimates of thesSize and abundance of a pelagic Gonostomatid fish (Cyclothone pallida) off the Bahamas. Journal of the Marine Biological Association of the United Kingdom, 81:869-871
  • McClain, C.R. and Rex, M.A. (2001) The relationship between dissolved oxygen concentration and maximum size in deep-sea Turrid gastropods: an application of quantile regression. Marine Biology, 139: 681-685