AMNH Trilobite Research

Melanie Hopkins, Ph.D.
Assistant Curator, Invertebrate Paleontology, Division of Paleontology 
Assistant Professor, Richard Gilder Graduate School
Melanie Hopkins Profile Image

Research Interests

Dr. Hopkins’s research focuses on the study of morphological evolution in the fossil record. She combines species-level phylogenetic analysis with high-resolution biostratigraphy in order to create frameworks for testing hypotheses about the role of geographic variation, ontogenetic variation, and modularity in the evolution of different clades. She also studies the interaction between different measures of diversity and the circumstances under which morphological, taxonomic, and functional diversity are decoupled. She has dabbled in global change biology and paleoecology and remains interested in niche evolution, particularly in its potential association with morphological evolution and speciation. Other recent projects demonstrated pervasive mosaic evolution throughout the fossil record, and explored how decisions made by scientists regarding what traits to measure influence the study of rates and modes of evolution.
Dr. Hopkins’s taxonomic interest lies with arthropods. Most of her research focuses on the paleobiology and early evolutionary history of trilobites, but she has also studied variation in extant fiddler crabs. Her research makes use of a variety of quantitative methods, most notably geometric morphometrics. Many projects are specimen based and rely on the extensive use of museum and new field collections. Other projects have made use of community databases, such as the Paleobiology Database. She is active in field work, particularly the Great Basin of the western U.S.


2017          Hopkins MJ, Chen F, Hu S, Zhang Z. The oldest known digestive system consisting of both paired digestive glands and a crop from exceptionally preserved trilobites of the Guanshan Biota (Early Cambrian, China). PLOSone doi: 10.1371/journal.pone.0184982

2017          Kröger B, Finnegan S, Franeck F, Hopkins MJ. The Ordovician succession adjacent to Hinlopenstretet, Ny Friesland, Spitsbergen. American Museum Novitates: 3882: 28 p. doi: 10.1206/3882.1.

2017          Rubin M, Lamsdell JC, Prendini L, Hopkins MJ. Exocuticular hyaline layer of sea scorpions and horseshoe crabs suggests cuticular fluorescence is plesiomorphic in chelicerates. Journal of Zoology. doi: 10.1111/jzo.12493

2017          Hopkins MJ, Sylvain G. Morphological disparity. In Nuño de la Rosa, Müller, Erwin (eds).Evolutionary Developmental Biology – a Reference Guide. Springer. doi:10.1007/978-3-319-33038-9_132-1.

2017          Hopkins MJ. Development, trait evolution, and the evolution of development in trilobites.Integrative and Comparative Biology 57:488-498. 

2017          Lamsdell JC, Congreve CR, Hopkins MJ, Krug AZ, Patzkowsky M. Phylogenetic paleoecology: tree-thinking and ecology in deep time. Trends in Ecology and Evolution 32:452-463.

2017          Hopkins MJ. How well does a part represent the whole? A comparison of cranidial shape evolution with exoskeletal character evolution in the trilobite family Pterocephaliidae.Palaeontology 60:309-318.

2017          Bapst DW, Hopkins MJ. Comparing cal3 and other a posteriori time-scaling approaches in a case study with the pterocephaliid trilobites. Paleobiology 43: 49-67.


2016          Hopkins MJ, Pearson JK. Non-linear ontogenetic shape change in Cryptolithus tesselatus(Trilobita) using three-dimensional geometric morphometrics. Palaeontologia Electronica19.3.42A.

2016          Hopkins MJ, Lidgard S. Fossil species lineages and their defining traits—taxonomic usefulness and evolutionary modes. In Allmon, W.D., and Yacobucci, M.M. (eds.), Species and Speciation in the Fossil Record. University of Chicago Press, pp. 366-388.

2016          Hopkins MJ, Haber A, Thurman CL. Constraints on geographic variation in fiddler crabs (Ocypodidae: Uca) from the western Atlantic. Journal of Evolutionary Biology, 29:1553-1568.

2016          Hopkins MJ. Magnitude versus direction of change and the contribution of macroevolutionary trends to morphological disparity. Biological Journal of the Linnean Society, 118: 116-130.


2015          Hopkins MJ, Lidgard S. Gradualism, in Losos, J. B., ed., Oxford Bibliographies on Evolutionary Biology: New York, Oxford University Press. DOI:10.1093/OBO/9780199941728-0072

2015          Hunt G, Hopkins MJ, Lidgard S. Simple versus complex models of trait evolution, and stasis as a response to environmental change, Proceedings of the National Academy of Sciences USA, v. 112, no. 16, p. 4885-4890.

2015          Hopkins MJ, Smith AB. Dynamic evolutionary change in post-Paleozoic echinoids, and the importance of scale when interpreting rates of evolution: Proceedings of the National Academy of Sciences USA, v. 112, no. 2, p. 3758-3763.

2015          Lidgard S, Hopkins MJ, 2015, Stasis, in Losos, J. B., ed., Oxford Bibliographies on Evolutionary Biology: New York, Oxford University Press. DOI:10.1093/OBO/9780199941728-0067


2014          Hopkins MJ. Environmental patterning of trilobite morphological disparity. Paleobiology40:352-373.

2014          Hopkins MJ, Simpson C, Kiessling W. Differential niche dynamics among major marine invertebrate clades, Ecology Letters 17: 314-323. doi:10.1111/ele.12232.

2014          Seddon AWR, +68 others including Hopkins MJ. Looking forward through the past. Identification of fifty priority research questions in palaeoecology. Journal of Ecology 102: 256-267. doi:10.1111/1365-2745.12195.

2014          Hampton KR, Hopkins MJ, McNamara JC, Thurman CL. Intraspecific variation in carapace morphology among eight Species of Fiddler Crabs (Genus Uca) from the Atlantic coast of Brazil. Aquatic Biology 20: 53-67. doi:10.3354/ab00545.

2014          Wieman AC, Berendszen PB, Hampton KR, Jang J, Hopkins MJ, Jurgenson J, McNamara JC, Thurman CL. A panmictic fiddler crab from the coast of Brazil? Impact of divergent ocean currents and larval dispersal potential on genetic and morphological variation in Uca maracoani. Marine Biology 161: 173-185.


2013          Korn D, Hopkins MJ, Walton, SA. Extinction space—a method for the quantification and classification of changes in morphospace across extinction boundaries. Evolution 67: 2795-2810. doi:10.1111/evo.12162.

2013          Hopkins MJ. Decoupling of taxomonic diversity and morphological disparity during decline of the Cambrian trilobite family Pterocephaliidae. Journal of Evolutionary Biology26:1665-1676. doi:10.1111/jeb.12164.


2012          Hopkins MJ, Lidgard S. Evolutionary mode varies amongst morphological traits in fossil species lineages. Proceedings of the National Academy of Sciences 109: 20520-20525. doi: 10.1073/pnas.1209901109.


2011          Hopkins MJ. How species longevity, intraspecific morphological variation, and geographic range size are related: a comparison using late Cambrian trilobites. Evolution 65: 3252-3273. doi: 10.1111/j.1558-5646.2011.01379.x.

2011          Gerber S, Hopkins MJ. Mosaic heterochrony and evolutionary modularity: The trilobite genus Zacanthopsis as a case study. Evolution 65: 3241-3252. doi: 10.1111/j.1558-5646.2011.01363.x.

2011          Hopkins MJ. Species-level phylogenetic analysis of the Pterocephaliidae (Trilobita) from the Great Basin, western USA.  Journal of Paleontology 85: 1128-1153.


2010          Hopkins MJ, Thurman CL. The geographic structure of morphological variation in eight species of fiddler crabs (Ocypodidae: genus Uca) from the eastern United States and Mexico. Biological Journal of the Linnean Society 100: 248-270.


2009          Hopkins MJ, Webster M. Ontogeny and geographic variation of a new species of the corynexochine trilobite Zacanthopsis (Dyeran, Cambrian). Journal of Paleontology 83: 524-547.


2008          Hopkins MJ, Webster M. Morphological and ontogenetic change in the “Early” Cambrian trilobite Zacanthopsis during an interval of environmental change. Pp. 185-187 in Rábano, I., Gozalo, R., and García-Bellido, D (eds.), Advances In Trilobite Research. Cuadernos del Museo Geominero 9. Instituto Geológico y Minero de España, Madrid.


2007          Ludington S, Moring BC, Miller RJ, Stone PA, Bookstrom AA, Bedford DR, Evans JG, Haxel GA, Nutt CJ, Flyn KS, Hopkins MJ. Preliminary integrated geologic map databases for the United States. USGS Open-File Report 2005-1305.


2006          Dusel-Bacon C, Hopkins MJ, Mortensen JK, Williams I, Helsop K, Dashevsky SS, Bressler JR, Day WD. Paleozoic tectonic and metallogenic evolution of the Yukon-Tanana terrane, east-central Alaska, in, Colpron, Nelson, and Thompson, eds., Paleozoic Evolution and Metallogeny of Pericratonic Terranes at the Ancient Pacific Margin of North America, Canadian and Alaskan Cordillera: Geol. Assoc. of Canada, Spec. Paper, 45, p. 25-74.


2004          Dusel-Bacon C, Wooden J, Hopkins, MJ. U-Pb zircon and geochemical evidence for bimodal mid-Paleozoic magmatism and syngenetic base-metal mineralization in the Yukon-Tanana terrane, Alaska: GSA Bulletin 116: 989-1015.

2004          Glen JMG, McKee EH, Ludington S, Ponce DA, Hildenbrand TG, Hopkins MJ. Geophysical terranes of the Great Basin and parts of surrounding provinces: USGS Open-File Report 04-1008.


2003          Sloan J, Henry CD, Hopkins MJ, Ludington S. revised, National Geochronological Database: USGS Open-File Report 03-236,