The Great Fossil Enigma

by Simon J. Knell

  9. E. L. Yochelson, “Introduction,” in Proceedings of the North American Paleontological Convention, vol.1 (Lawrence, Kans.: Allen Press, 1970). Thanks to Derek Briggs and Dick Aldridge for this important source.

  10. Austin (pers. comm.) recalled this rumor, though he did not subscribe to it himself. Rhodes, pers. comm., 29 October 2010.

  11. William G. Melton died on December 25, 1991. He was sixty-eight. He was the preparator of vertebrate paleontology under Claude W. Hibbard from March 1957 to August 1966 and worked with him for many summers in Meade, Kansas. Geoscience News, University of Michigan alumni news letter, December 1992, http://www.geo.lsa.umich.edu/geonews/archive/9212.pdf/.

  12. Pander Society Letter 2 (October 1969).

  13. E. S. Richardson, “The conodont animal,” Earth Science 6 (1969): 256–57.

  14. Rhodes expressed his skepticism of the Melton and Scott animal in the book in which it was published, and again with Austin in the Treatise published in 1981, though he did so with such delicacy that readers, including Scott, may have been uncertain precisely where he stood on the matter. Certainly, he did not conclusively support their interpretation. Frank Rhodes, pers. comm., 29 October 2010.

  15. R. J. Riedl, “Gnathostomulisa from America,” Science 163 (1969): 445–52; C. J. Durden, J. Rogers, E. L. Yochelson, and R. J. Riedl, “Gnathostomulida: Is there a fossil record? (correspondence),” Science 164 (1969): 855–56; O. Wetzel, “Die in organischer substanz erhaltenen mikrofossilien des baltischen Kriedefeuersteins,” Palaeontogr. Abt. A. Paleozoool.-Stratigr. 78 (1933): 1–110.

  16. John R. Horner (b. 15 June 1946) would become a distinguished palaeontologist who demonstrated the sociability of some dinosaurs and later provided technical advice for the Jurassic Park films.

  17. Pander Society Letter 4 (August 1970).

  18. W. G. Melton and H. W. Scott, “Conodont-bearing animals from the Bear Gulch Limestone, Montana,” in F. H. T. Rhodes (ed.), Conodont Paleozoology, GSA Special Paper 141; L. B. Halstead, The Pattern of Vertebrate Evolution (San Francisco: Freeman 1969).

  19. Pander Society Letter 4 (August 1970).

  20. Scott, “New specimens.”

  12. THE INVENTION OF LIFE

  1. K. Fahlbusch, “Bildung von Calciumphosphat bei fossilen Algen,” Naturwissenschaften 50 (1973): 517–18; K. Fahlbusch, “Die stellung der Conodontida im biologischen system,” Palaeontographica A 123 (1964): 137–201; Lindström, Conodonts, 121; H. Beckmann et al., “Sind Conodontent Reste fossiler Algen?” N. Jb. Geol. Paläont. Abh. 7 (1965): 385–99. On Nease, Pander Society Newsletter 3 (1969).

  2. Lindström, Conodonts, 123–30.

  3. H. Pietzner et al., “Zur chemischen Zusammensetzung and Mikromorphologie der Conodonten,” Palaeontographica 128 (1968): 115–52. The first fossils to be studied in this way were brachiopods and bivalves, for which, Barnes, Rexroad, and Miller, “Lower Paleozoic,” 3; R. W. Pierce and R. L. LangenheimJr., “Ultrastructure in Palmatolepis sp. and Polygnathus sp.,” GSA Bull. 80 (1969): 1397–1400.

  4. K. J. Müller, “Bürstenbildungbei Conodonten,” Palaeont. Z. 43 (1969): 64–71; K. J. Müller and Y. Nogami, “Ϝber den feinbau der Conodonten,” Mem. Fac. Sci., Kyoto Univ., Geol. and Min. 38 (1971): 1–87; K. J. Müller, “Micromorphology of elements: Internal structure,” in R. A. Robison (ed.), Treatise of Invertebrate Paleontology, pt. W, suppl. 2, Conodonta (Boulder, Colo./Lawrence: GSA and Univ. Kansas Press, 1981), W20–41; P. C. J. Donoghue, “Growth and patterning in the conodont skeleton,” Phil. Trans. R. Soc. Lond., ser. B, 353 (1998): 633–66.

  5. C. R. Barnes, D. B. Sass, and E. A. Monroe, “Preliminary studies of the ultrastructure of selected Ordovician conodonts,” R. Ont. Mus. Life Sci. Contrib. 76 (1970): 1–24; C. R. Barnes, D. B. Sass, and M. L. S. Poplawski, “Conodont ultrastructure,” R. Ont. Mus. Life Sci. Contrib. 90 (1973): 1–36.

  6. F. H. T. Rhodes (ed.), Conodont Paleozoology, GSA Special Paper 141, vii.

  7. M. Lindström, “On the affinities of conodonts,” in F. H. T. Rhodes (ed.), Conodont Paleozoology, GSA Special Paper 141, 85–102; M. Lindström, “The conodont apparatus as a food-gathering mechanism,” Palaeontology 17 (1974): 729–44, 731–32.

  8. S. Rietschel, “Zur Deutung der Conodonten,’ Natur und Museum 103 (1973): 409–18; F. R. Schram, “Pseudocoelomates and a nemertine from the Illinois Pennsylvanian,” J. Paleont. 47 (1973): 985–89.

  9. Lindström, “On the affinities.”

  10. S. Conway Morris, “A new Cambrian lophophorate from the Burgess Shale of British Columbia,” Palaeontology 19 (1976): 199–222.

  11. This was Protohertzina discovered by Missarzhevskij, see S. Bengtson, “The structure of some Middle Cambrian conodonts, and the early evolution of conodont structure and function,” Lethaia 9 (1976): 185–206, 185.

  12. Gould, Wonderful Life, 149; B. F. Glenister et al., “Conodont pearls?” Science 193 (1976): 571–73; D. McConnell et al., “Nautiloid uroliths composed of phosphatic hydrogel,” Science 199 (1978): 208–209. Donoghue later suggested these pearls belonged to an extinct group of bryozoans.

  13. J. Priddle, “The function of conodonts,” Geol. Mag. 111 (1974): 255–57; Priddle to Scott, 24 January 1974, Scott to Priddle, 4 February 1974, Box 1, Correspondence Re: Conodont Animal, Scott Papers.

  14. G. C. O. Bischoff, “On the nature of the conodont animal,” Geol. & Palaeont. 7 (1973): 147–74.

  15. J. Hofker, “Eine mögliche Tiergruppe, welche die Trägerin der sogenannten Conodonten war,” Palaeont. Z. 48 (1974): 29–35.

  16. Bengtson, “Structure.”

  17. S. Bengtson, “Conodonts: The need for a functional model,” Lethaia 13 (1980): 320 admits to this attraction.

  18. K. J. Müller and D. Andres, “Eine conodontengruppe von Prooneotodus tenuis (Müller, 1959) in natürlichen Zusammenhang aus dem Oberen Kambrium von Schweden,” Palaeont. Z. 50 (1976): 193–200; P. Carls, “Could conodonts be lost and replaced?” N. Jb. Geol. Paläont. Abh. 155 (1977): 18–64.

  19. E. Landing, “‘Prooneotodus’ tenuis (Müller, 1959) apparatuses from the Taconic allochthon, eastern New York: Construction, taphonomy and the protoconodont ‘supertooth’ model,” J. Paleont. 51 (1977): 1072–84.

  20. R. S. Nicoll, “Conodont apparatuses in an Upper Devonian palaeoniscid fish from the Canning Basin, Western Austratlia,” BMRJ. Austral. Geol. and Geophys. 2 (1977): 217–28.

  21. V. H. Hitchings and A. T. S. Ramsay, “Conodont assemblages: A new functional model,” Paleogeog., Palaeoclimat., Palaeoecol. 24 (1978): 137–49.

  22. L. Jeppsson, “Conodont element function,” Lethaia 12 (1979): 153–71.

  23. S. Conway Morris, “Conodont function: Fallacies of the tooth model,” Lethaia 13 (1980): 107–108; L. Jeppsson, “Function of the conodont elements,” Lethaia 13 (1980): 228; Bengtson, “Conodonts.”

  24. H. Szaniawski, “Chaetognath grasping spines recognized among Cambrian protoconodonts,” J. Paleont. 56 (1982): 806–10; H. Szaniawski, “Structure of protoconodont elements,” Fossils and Strata 15 (1983): 21–27; Sweet, Conodonta 174.

  25. R. Buchsbaum, Animals without Backbones (Harmondsworth, UK: Penguin, 1951), 1:199–200.

  26. K. J. Müller, “Zoological affinities of conodonts,” in R. A. Robison (ed.), Treatise of Invertebrate Paleontology, pt. W, suppl. 2, Conodonta (Boulder, Colo./ Lawrence: GSA and Univ. Kansas Press, 1981), W78–W82.

  13. EL DORADO

  1. This chapter has, in addition to published resources, drawn upon an unpublished book-length account Dick Aldridge wrote of his scientific research, in part published in R. J. Aldridge and D. E. G. Briggs, “The discovery of conodont soft tissue anatomy and its importance for understanding the early history of vertebrates,” in D. Sepkoski and M. Ruse (eds.), The Paleobiological Revolution (Chicago: University of Chicago Press, 2009), 73–88. This chapter differs considerably from that account by attempting to locate a broader overview of debate in a longer history of discovery. Derek Briggs and Euan Clarkson read a late draft of th
is chapter and offered some important correctives to factual accuracy. Walt Sweet and Neil Clark provided me with recollections. My last task was to interrogate the extensive files of correspondence that Dick Aldridge had gathered together from various actors in the drama. For the sake of brevity, I have not given precise references to these resources below.

  2. D. E. G. Briggs, “The search for paleontology's most elusive entity: The conodont animal,” Field Mus. Nat. Hist. Bull. 55 (1984): 11–18; D. E. G. Briggs, E. N. K. Clarkson, and R. J. Aldridge, “Conodont,” McGraw-Hill Yearbook of Science and Technology 1985 (New York: McGraw-Hill, 1984), 132–35; D. E. G. Briggs and E. N. K. Clarkson, “The Lower Carboniferous Granton ‘shrimp bed,’ Edinburgh,” in D. E. G. Briggs and P. D. Lane (eds.), Trilobites and Other Early Arthropods, Palaeontological Association Special Papers in Palaeontology 30, 616–77 (1983); D. E. G. Briggs, N. D. L. Clark, and E. N. K. Clarkson, “The Granton ‘shrimp-bed,’ Edinburg – a Lower Carboniferous KonservatLagerstätte,” Trans. Roy. Soc. Edinb. Earth Sci. 82 (1991): 65–85; D. Tait, “Notice of a shrimp-bearing limestone in the Calciferous Sandstone Series at Granton, near Edinburgh,” Trans. Edinb. Geol. Soc. 11 (1924): 131–15.

  3. D. E. G. Briggs, E. N. K. Clarkson, and R. J. Aldridge, “The conodont animal,” Lethaia 16 (1983): 1–14.

  4. Gould, “Nature's great era,” 12.

  5. J. J. Hearty, “A day at Granton Harbour-conodont II,” MAPS [Mid-America Paleontological Society] Digest, November 1984.

  6. S. Bengtson, “A functional model for the conodont apparatus,” Lethaia 16 (1983): 38; S. Bengtson, “The early history of the Conodonta,” Fossils and Strata 15 (1983): 5–19.

  7. J. Dzikand D. Drygant, “The apparatus of panderodontid conodonta,” Lethaia 19 (1986): 133–41.

  8. W. Sweet, “Conodonts: Those fascinating little whatzits,” J. Paleont. 59 (1985): 485–94.

  9. R. J. Aldridge and D. E. G. Briggs, “Conodonts,” in A. Hoffman and M. H. Nitecki (eds.), Problematic Fossil Taxa (Oxford: Oxford University Press, 1986), 227.

  10. P. Janvier, “Conodont affinity: A reply,” Lethaia 21 (1988): 27; P. Janvier, “‘L'animal-conodonte’ enfin demasqué?” Recherche 14, no. 145 (1983): 832–33.

  11. J. K. Rigby Jr., “Conodonts and the early evolution of the vertebrates,” GSA Abstracts with Programs 15 (1983): 671.

  12. R. S. Nicoll, “Multielement composition of the conodont species Polygnathus xylus xylus Stauffer, 1940 and Ozarkodina brevis (Bischoff & Ziegler, 1957) from the Upper Devonian of the Canning Basin, Western Australia,” BMR J. Austral. Geol. Geophys. 9 (1985): 133–47, 146.

  13. D. G. Mikulic, D. E. G. Briggs, and J. Kluessendorf, “A Silurian soft-bodied biota,” Science 228 (1985): 715–17; D. G. Mikulic, D. E. G. Briggs, and J. Kluessendorf, “A new exceptionally preserved biota from the Lower Silurian of Wisconsin, USA,” Phil. Trans. Roy. Soc. Lond., ser. B, 311 (1985): 78–85.

  14. R. J. Aldridge, M. P. Smith, R. D. Norby, and D. E. G. Briggs, “The architecture and function of Carboniferous polygnathacean conodont apparatuses,” in R. J. Aldridge (ed.), Palaeobiology of Conodonts (Chichester, UK: Ellis Horwood, 1987), 63–75.

  15. D. E. G. Briggs and S. H. Williams, “The restoration of flattened fossils,” Lethaia 14 (1981): 157–64.

  16. M. P. Smith, D. E. G. Briggs, and R. J. Aldridge, “A conodont animal from the lower Silurian of Wisconsin, USA, and the apparatus architecture of panderodontid conodonts,” in Aldridge, Palaeobiology of Conodonts, 91–104.

  17. Aldridge, “Conodont palaeobiology” (see ch. 4, n. 15).

  18. R. S. Nicoll, “Form and function of the Pa element in the conodont animal,” and R. S. Nicoll and C. B. Rexroad, “Reexamination of Silurian conodont clusters from Northern Indiana,” both in Aldridge, Palaeobiology of Conodonts, 77–90.

  19. H. Szaniawski, “Preliminary structural comparisons of protoconodont, paraconodont and euconodont elements,” in Aldridge, Palaeobiology of Conodonts, 35–47.

  20. R. J. Aldridge, D. E. G. Briggs, E. N. K. Clarkson, and M. P. Smith, “The affinities of conodonts – new evidence from the Carboniferous of Edinburgh, Scotland,” Lethaia 19 (1986): 279–91; M. Benton, “Conodonts classified at last,” Nature 325 (1987): 482–83.

  21. Mashkova, “Ozarkodina” (see ch. 8, n. 22); J. Dzik, “Chordate affinities of the conodonts,” in Hoffman and Nitchki, Problematic Fossil Taxa, 240–54.

  22. R. P. S. Jefferies, The Ancestry of the Vertebrates (Cambridge: Cambridge University Press, 1986).

  23. G. S. Nowlan and D. B. Carlisle, “The cephalochordate affinities of conodonts,” Can. Paleont. Biostrat. Seminar, Prog. Abstracts (1987): 7.

  24. Janvier, “Conodont affinity: A reply.”

  25. S. Tillier and J. P. Cuif, “L'animale-conodonte est-il un mollusque Aplacophore,” Cr. Hebd. Séanc. Acad. Sci., Paris 303 (1986): 627–32; S. Tillier and P. Janvier, “Le retour de l'animal-conodonte,” Recherche 17 (1986): 1574–1575; D. E. G. Briggs, R. J. Aldridge, and M. P. Smith, “Conodonts are not aplacophoran mollusks,” Lethaia 20 (1987): 381–82.

  26. Sweet, Conodonta (see ch. 6, n. 8). A book had been produced in Chinese but had limited impact.

  27. See also H. Gee, “Four legs to stand on…,” Nature 342 (1989): 738–39.

  28. R. J. Aldridge and D. E. G. Briggs, “Sweet talk,” Paleobiology 16 (1990): 241–46.

  29. M. P. Smith, “The Conodonta – Palaeobiology and evolutionary history of a major Palaeozoic chordate group,” Geol. Mag. 127 (1990): 365–69.

  30. S. Conway Morris, “Typhloesus wellsi (Melton and Scott, 1973), a bizarre metazoan from the Carboniferous of Montana, USA,” Phil. Trans. Roy. Soc. Lond., ser. 327 (1990): 595–624, is the most comprehensive account. The author presented on the animal in the United States in 1979. That account was not published until 1985.

  31. Gould, Wonderful Life, 148; D. E. G. Briggs, and S. Conway Morris, “Problematica from the Middle Cambrian Burgess Shale of British Columbia,” in Hoffman and Nitecki, Problematic Fossil Taxa, 167–83. Bengtson and others published on this animal in 2006.

  32. R. Fortey, “Shock lobsters,” review of Conway Morris's Crucible of Creation, Lond. Rev. Books 20, no. 19 (1998).

  33. S. Conway Morris, “Conodont palaeobiology: Recent progress and unsolved problems,” Terra Nova 1 (1989): 135–50, 141.

  14. OVER THE MOUNTAINS OF THE MOON

  1. This account of the Soom Shale investigation draws upon Dick Aldridge's unpublished account and correspondence files (see ch. 13, n. 1). I am also grateful, via Dick, to Hannes Theron for recounting details of the discovery.

  2. J. N. Theron and E. Kovacs-Endrody, “Preliminary note and description of the earliest known vascular plant, or an ancestor of vascular plants, in the flora of the Lower. Silurian Cedarberg Formation, Table Mountain Group, South Africa,” S. African. J. Sci. 82 (1986): 102–105.

  3. R. J. Aldridge and J. N. Theron, “Conodonts with preserved soft tissue from a new Ordovician Konservat-Lagerstatte,” J. Micropalaeo. 12 (1993): 113–17; A. Ritchie, “New evidence on Jamoytius kerwoodi White, an important ostracoderm from the Silurian of Lanarkshire, Scotland,” Palaeontology 11 (1968): 21–39.

  4. R. J. Aldridge, J. N. Theron, and S. E. Gabbott, “The Soom Shale: A unique Ordovician fossil horizon in South Africa,” Geology Today 10 (1994): 218–21.

  5. R. J. Krejsa, P. Bringas, and H. C. Slavkin, “A neontological interpretation of conodont elements based on agnathan cyclostome tooth structure, function and development,” Lethaia 23 (1990): 369–78; R. J. Krejsa, P. Bringas, and H. C. Slavkin, “The cyclostome model: An interpretation of conodont element structure and function based on cyclostome tooth morphology, function and life history,” Cour. Forsch.-Inst. Senckenberg 118 (1990): 473–92.

  6. M. M. Smith and B. K. Hall, “Development and evolutionary origins of vertebrate skeletogenic and odontogenic tissues,” Biol. Rev. 65 (1990): 277–373; R. J. Aldridge et al., “The anatomy of conodonts,” Phil. Trans. Roy. Soc., ser. B, 340 (1993): 405–21.<
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  7. D. K. Elliot, A. R. M. Blieck, and P. -Y. Gagnier, “Ordovician vertebrates,” in C. R. Barnes, and S. H. Williams (eds.), Advances in Ordovician Geology, Geological Survey of Canada Paper 90–9, 93–106 (1991).

  8. D. Palmer, “Early vertebrates given new teeth,” New Scientist, 29 August 1982, 16.

  9. I. J. Sansom et al., “Presence of earliest vertebrate hard tissues in conodonts,” Science 256 (1992): 1308–11.

  10. M. Smith, I. J. Sansom and P. Smith, “‘Teeth’ before armour: The earliest vertebrate mineralized tissues,” Modern Geology 20 (1996): 303–19, a paper presented in 1993 and updated during delayed publication.

  11. N. Nuttal, “Razor-toothed fish bites into human history,” Times, 10 June 1992; “Limestone yields the oldest set of teeth,” Independent, 10 June 1992; J. H., “Teething troubles,” Telegraph, 22 June 1992; Palmer, “Early vertebrates.”

  12. Discover, January 1993, 68; Northern Echo, 11 June 1992.

  13. C. R. Barnes, R. Fortey, and S. H. Williams, “The patterns of global bioevents during the Ordovician Period,” in O. H. Walliser (ed.), Global Events and Event Stratigraphy in the Phanerozoic (Berlin: Springer-Verlag, 1996), 142; D. E. G. Briggs, “Conodonts – a major extinct group added to the vertebrates,” Science 256 (1992): 1285–86; Aldridge, Theron, and Gabbott, “Soom Shale,” 220–21; H. Gee, Deep Time: Cladistics, the Revolution in Evolution (London: Fourth Estate, 2000); H. Gee, Before the Backbone (London: Chapman & Hall, 1996).