The Contributions of David Malcolm Raup (24 April 1933–9 July 2015)
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Paleobiology, 42(1), 2016, pp. 172–183 DOI: 10.1017/pab.2015.54 Invited Essay IN MEMORIAM The Contributions of David Malcolm Raup (24 April 1933–9 July 2015) Michael Foote and Arnold I. Miller Michael Foote. Department of the Geophysical Sciences, University of Chicago, Chicago, Illinois 60637, U.S.A. E-mail:[email protected] Arnold I. Miller. Department of Geology, University of Cincinnati, Cincinnati, Ohio 45221, U.S.A. E-mail:[email protected] Submitted: 15 October 2015 Accepted: 9 November 2015 In recounting the exploits of the renowned do the talking; accommodating one’s own self- test pilot and World War II ace Chuck Yeager, doubts but not being defeated by them— Tom Wolfe (1979) observed that Yeager’s calm, profoundly influenced those who were lucky West Virginian drawl can still be heard in the enough to spend appreciable time around him voices of virtually all commercial pilots, dec- and, through this group, subsequent genera- ades after Yeager became the first to break the tions of students who have no idea that the sound barrier. This inflection caught on in the “voice” they are really hearing and, in turn, are late 1940s among a cadre of Yeager’s disciples seeking to emulate, is Dave Raup’s. at an airfield in the high desert of California, Dave’searliestwork,influenced in part by who sought to emulate the “ace of aces,” and it Ernst Mayr’s interest in geographic variation in spread further, from generation to generation, morphology and its relevance to the speciation aided by the participation of many of those process, concerned allometric, geographic, and disciples as astronauts in NASA’s manned environmental variation in the living sand dollar space program. During the heady days of the Dendraster (bibliog. 1–2). Among other results, Mercury, Gemini, and Apollo programs, the he made a convincing case for the ecophenotypic drawl and demeanor could be heard regularly basis of some among-population differences in in televised exchanges between astronauts and shape, and noted that many putative species- mission control. Little did any of us know that level differences among fossil populations are the voice was really Chuck Yeager’s. consistent with non-genetic variation in living Wolfe’s description of Yeager’sinfluence on populations. This work already exemplified the his peers reminds us that, in any field, there are careful analysis, logic, and attention to modern a few people whose work is so transcendent ecology and evolutionary biology that would that, by dint of the examples they set, colleagues come to characterize Dave’ssubsequent seek to emulate not only their methods, but also contributions. how they carry themselves in the arena. And so The Dendraster work was followed by a it was with Dave Raup, one of the most series of papers documenting the crystallo- influential paleontologists of the past half- graphic axis orientations of plates in the century, who died this past summer after a echinoid test (bibliog. 3–4, 6–8, 13, 18–19). brief illness. As is often true of people who These demonstrated that c-axis orientations become the best of the best, Dave did not are largely fixed within echinoid species and at actively seek the limelight. In fact, he tended to higher taxonomic levels; that species show avoid it and was never particularly comfortable ontogenetic variation following a few general as the center of attention in any forum. But the patterns; and that groups of plates within a way he carried himself—actively seeking out species often vary consistently from one holes in his own results; not dismissing some- another. Dave used the phylogenetic signal one else’sworkwithoutfirst fully understand- evident in cases where higher taxonomic ing it; letting one’s work, rather than one’sego, affinities are fairly well known as a basis for © 2016 The Paleontological Society. All rights reserved. 0094-8373/16 DAVID M. RAUP (1933–2015) 173 suggesting solutions where affinities are less theoretical morphology—acomparisonbetween clear. He also tackled the functional signifi- actual and theoretically possible forms, the latter cance of axis orientations, ultimately arguing in turn developed from generative models such for the relevance of light penetration, in view of as that for logarithmic coiling. By comparing the the among-species covariation in light sensi- spectrum of possible forms to those that had tivity and axis orientation, and suggesting that actually evolved, Dave was able to use a light penetration in the apical plates might combination of architectural, phylogenetic, and even play a role in navigation. He also argued functional arguments to make sense of why that c-axes orthogonal to the plate surface bivalves, gastropods, brachiopods, and ammo- facilitated the ontogenetic development of noids occupy largely distinct regions of the plate curvature. A study of teratologies in coiling-parameter space (bibliog. 20). He also Strongylocentrotus demonstrated that crystal- demonstrated that the concentration of ammo- lography was inverted when plate position noids in certain regions of the coiling space is was inverted, and that the missing plates in unlikely to reflect optimization of a single tetraradiate specimens could be identified. functional demand such as stability or shell Toward the end of Dave’s echinoid period, efficiency, and therefore probably reflects he and geochemist Jon N. Weber documented a tradeoff resulting from multiple demands carbon- and oxygen-isotopic variation in echi- (bibliog. 21). noid plates (bibliog. 14, 16–17, 24). As with the Dave started with a consideration of gastro- crystallographic data, different components of pod coiling (bibliog. 5, 9), but eventually the skeleton vary systematically, and the modified and extended the model to other isotopes carry a phylogenetic signal—one that coiled forms (bibliog. 12, 20–22, 35–36) and matches the signal in the c-axes and suggests even developed a soap-bubble model of echi- solutions to taxonomic problems. Although noid plating (bibliog. 25), a model for helical oxygen isotopes are somewhat sensitive to bryozoans such as Archimedes (bibliog. 69, 133), temperature, they show enough genetic varia- and an algorithm for generating grazing traces tion to limit the use of echinoids for paleo- from a few simple rules with an added environmental inference. Taxonomic variation in stochastic element (bibliog. 28). In the last carbon isotopes suggests metabolic differences example, his simulation program occasionally among clades, and the taxonomic diversification generated “mistakes”—traces that looked like of echinoids since the mid Paleozoic correlates no ichnofossils ever found. He thought the with increased variance in isotopic composition. algorithm might not be working, but his This body of work represents one of the earliest collaborator Dolf Seilacher found sense in the demonstrations of vital effects in stable isotopic mistakes by noting that they mimicked sub- composition. optimal plowing patterns that he had seen in Judging from citations to his publications, the rural Swabia, when farmers didn’t plan prop- work discussed so far seems to have been of erly and ended up crossing their own furrows! interest mainly to students of echinoids, and Although Dave evidently realized the great even then the application and extension of potential of theoretical morphology from the Dave’s findings to phylogenetic problems has start, laying out possible applications to onto- been limited (for echinoid examples, see Emlet geny, phylogeny, ecology, and adaptation, his 1988 and Kroh and Smith 2010). However, a few treatment in his earliest papers seems somewhat paleontologists, notably Dan Fisher and his cautious, referring to the coiling model mainly students, have gone on to apply crystallography as an objective way to describe gastropod form, to the systematics of other echinoderm groups, in lieu of terms such as “turbiniform” or including stylophorans, crinoids, and blasto- “turriculate,” and stating that, “the objectives zoans (Fisher and Cox 1988; Bodenbender 1996; are practical rather than theoretical” (bibliog. 5: Bodenbender and Ausich 2000; Bodenbender p. 603). Likewise, he commented that his and Hiemstra 2004). insightful analysis of ammonoid coiling, “is While Dave was engaged with echinoids, he primitive in many regards” (bibliog. 21: p. 65). began a long-term research program in Downplaying the innovative aspects of his 174 MICHAEL FOOTE AND ARNOLD I. MILLER work is something that would characterize areas, such as image analysis and biostrati- Dave’s papers for his entire career; understate- graphy, but that they had clearly succeeded in ment and claims that his approaches were the areas of mathematical modeling and simu- rather similar to what others had already done, lation, and were likely in the coming years to differing only in emphasis, were to become enable “increasingly ambitious analyses of recognizable aspects of his style. (Even mun- large data sets having to do with distribution dane titles often belied clever and groundbreak- of fossil taxa in time and space” (bibliog. 60: ing analyses; see [bibliog. 62], for example.) A p. 269). His advocacy of computing was but one common theme that emerges in the echinoid example of a lifelong dedication to improving soap-bubble work and the simulation of grazing the infrastructure of paleontology. Others traces is that, even though we do not know include his collaboration with Bernie Kummel whether the model is biologically realistic, its on Handbook of Paleontological Techniques ability to generate forms so similar to what we (bibliog. 15); his chairmanship of the National see argues that the “rules” an organism follows Research Council’s Committee on Guidelines need not exceed the complexity of the model. for Paleontological Collecting (bibliog. 103); the Such statements of parsimony and a willingness workshop on “species as particles” that he to entertain unconventional ideas would taught with Tom Schopf at the Smithsonian in emerge in later work as well; for example, his 1978; and, of course, the two editions of conclusion that the available data allow the Principles of Paleontology, co-authored with possibility that species richness has not increased Steve Stanley (bibliog.