Skip to main content
    • Aa
    • Aa

An Early Cambrian radula

  • Nicholas J. Butterfield (a1)

Microscopic teeth isolated from the early Cambrian Mahto Formation, Alberta, Canada, are identified as components of a molluscan radula, the oldest on record. Tooth-rows are polystichous and lack a medial rachidian tooth-column. Anterior-posterior differences in tooth-row morphology are interpreted as ontogenetic and correspond broadly to the diversity of isolated teeth, some of which correspond closely with those of extant aplacophoran molluscs. Associated pock-marked cuticular fragments are interpreted as having supported multiple biomineralized sclerites/spines in the manner of a modern chiton girdle. On the assumption that the cuticle and radula derive from the same species, there is a strong case for identifying this fossil as an aculiferan (aplacophoran + polyplacophora) mollusc, possibly a stem-group chiton. Similarities between the Mahto radula and the feeding apparatus of Wiwaxia and Odontogriphus are shown to be superficial. Terminal wear on some of the Mahto teeth indicate that they were used to scrape hard-substrates.

Hide All
Beedham G. E. and Trueman E. R. 1967. The relationship of the mantle and shell of the Polyplacophora in comparison with that of other Mollusca. Journal of Zoology, 151:215231.
Beedham G. E. and Trueman E. R. 1968. The cuticle of the Aplacophora and its evolutionary significance in the Mollusca. Journal of Zoology, 154: 443451.
Bengtson S. 1992. The cap-shaped Cambrian fossil Maikhanella and the relationship between coeloscleritophorans and molluscs. Lethaia, 25:401420.
Bengtson S. and Conway Morris S. 1984. A comparative study of Lower Cambrian Halkieria and Middle Cambrian Wiwaxia. Lethaia, 17:307329.
Bengtson S. and Yue Z. 1992. Predatorial borings in late Precambrian mineralized exoskeletons. Science, 257:367369.
Brocco S. L., O'Clair R. M., and Cloney R. A. 1974. Cephalopod integument: The ultrastructure of Kölliker's organs and their relationship to chaetae. Cell Tissue Research, 151:293308.
Butterfield N. J. 1990. A reassessment of the enigmatic Burgess Shale fossil Wiwaxia corrugata (Matthew) and its relationship to the polychaete Canadia spinosa Walcott. Paleobiology, 16:287303.
Butterfield N. J. 2001. Cambrian food webs, p. 4043. In Briggs D. E. G. and Crowther P. R. (eds.), Paleobiology II, A Synthesis. Blackwell Scientific, Oxford.
Butterfield N. J. 2003. Exceptional fossil preservation and the Cambrian Explosion. Integrative and Comparative Biology, 43:166177.
Butterfield N. J. 2005. Reconstructing a complex early Neoproterozoic eukaryote, Wynniatt Fm., arctic Canada. Lethaia, 38:155169.
Butterfield N. J. 2006. Hooking some stem-group “worms”: Fossil lophotrochozoans in the Burgess Shale. BioEssays, 29:16.
Butterfield N. J. 2007. Macroecovolution and macroecology through deep time. Palaeontology, 50:4155.
Caron J.-B., Scheltema A., Schander C., and Rudkin D. 2006. A soft-bodied mollusc with radula from the Middle Cambrian Burgess Shale. Nature, 442:159163.
Caron J.-B., Scheltema A., Schander C., and Rudkin D. 2007. Reply to Butterfield on stem-group “worms”: Fossil lophotrochozoans in the Burgess Shale. Bioessays, 29:200202.
Cherns L. 2004. Early Palaeozoic diversification of chitons (Polyplacophora, Mollusca) based on new data from the Silurian of Gotland, Sweden. Lethaia, 37:445456.
Conway Morris S. 1985. The Middle Cambrian metazoan Wiwaxia corrugata (Matthew) from the Burgess Shale and Ogygopsis Shale, British Columbia, Canada. Philosophical Transactions of the Royal Society of London B, 307:507586.
Conway Morris S. 2006. Darwin's dilemma: The realities of the Cambrian ‘explosion’. Philosophical Transactions of the Royal Society B, 361:10691083.
Conway Morris S. and Menge Chen. 1991. Cambroclaves and paracarinachitids, early skeletal problematica from the Lower Cambrian of South China. Palaeontology, 34:357397.
Conway Morris S. and Peel J. S. 1995. Articulated halkieriids from the Lower Cambrian of North Greenland and their role in early protostome evolution. Philosophical Transactions of the Royal Society of London B, 347:305358.
Conway Morris S. and Caron J.-B. 2007. Halwaxiids and the early evolution of the lophotrochozoans. Science, 315:12551258
Doguzhaeva L., Mapes R. H., and Mutvei H. 1997. Beaks and radulae of early Carboniferous goniatites. Lethaia, 30:305313.
Eekhaut I., McHugh D., Mardulyn P., Tiedemann R., Monteyne D., Jangoux M., and Milinkovitch Michel C. 2000. Myzostomida: A link between trochozoans and flatworms? Proceedings of the Royal Society of London B, 267:13831392.
Eernisse D. J. and Kerth K. 1988. The initial stages of radular development in chitons (Mollusca: Polyplacophora). Malacologia, 28:95103.
Eernisse D. J. and Reynolds P. D. 1994. Polyplacophora, p. 55110. In Harrison F. W. and Kohn A. J. (eds.), Microscopic Anatomy of Invertebrates. Volume 5, Mollusca I. Wiley-Liss, New York.
Fritz W. H. and Mountjoy E. W. 1975. Lower and early Middle Cambrian formations near Mount Robson, British Columbia and Alberta. Canadian Journal of Earth Sciences, 12:119131.
Gabbot S. E. 1999. Orthoconic cephalopods and associated fauna from the late Ordovician Soom Shale Lagerstätte, South Africa. Palaeontology, 42: 123148.
Giribet G., Okusu A., Lindgren A. R., Huff S. W., Schrödl M., and Nishiguchi M. K. 2006. Evidence for a clade composed of molluscs with serially repeated structures: Monoplacophorans are related to chitons. Proceedings of the National Academy of Science, USA, 103:77237728.
Gordon D. P. 1975. The resemblance of bryozoan gizzard teeth to ‘annelidlike’ chaetae. Acta Zoologica, 56:283289.
Gosliner T. M. 1994. Gastropoda: Opisthobranchia, p. 253355. In Harrison F. W. and Kohn A. J. (eds.), Microscopic Anatomy of Invertebrates. Volume 5, Mollusca I. Wiley-Liss, New York.
Gubanov A. P. and Peel J. S. 2000. Cambrian monoplacophoran molluscs (Class Helcionelloida). American Malacological Bulletin, 15:139145.
Guralnick R. and Smith K. 1999. Historical and biomechanical analysis of integration and dissociation in molluscan feeding, with special emphasis on the true limpets (Patellogastropoda: Gastropoda). Journal of Morphology, 241:175195.
Gustus R. M. and Cloney R. A. 1972. Ultrastructural similarities between setae of brachiopods and polychaetes. Acta Zoologica, 53:229233.
Haas W. 1981. Evolution of calcareous hardparts in primitive molluscs. Malacologia, 21:403418.
Harper E. M. 2003. Assessing the importance of drilling predation over the Palaeozoic and Mesozoic. Palaeogeography, Palaeoclimatology, Palaeoecology, 201:185198.
Hausen H. 2005. Chaetae and chaetogenesis in polychaetes (Annelida). In Bartolomaeus T. and Purschke G. (eds.), Morphology, Molecules, Evolution and Phylogeny in Polychaeta and Related Taxa. Hydrobiologia, 535/536: 3752.
Hickman C. S. 1980. Gastropod radulae and the assessment of form in evolutionary paleontology. Paleobiology, 6:276294.
Hickman C. S. 1984. Implications of radular tooth-row functional integration for archaeogastropod systematics. Malacologia, 25:143160.
Hoare R. D. and Mapes R. H. 1986. The polyplacophoran “Chiton” carbonarious Stevens, 1858, in North America and new related species. Journal of Paleontology, 60:627635.
Hoffman S. 1949. Studien über das Integument der Solenogastren nebst Bemerkungen über die Verwandtschaft zwischen den Solenogastren und Placophoren. Zoologiska Bidrag från Uppsala, 27:293427.
Hou X., Bergström J., and Yang J. 2006. Distinguishing anomalocaridids from arthropods and priapulids. Geological Journal, 41:259269.
Hua H., Pratt B. R., and Zhang L.-Y. 2003. Borings in Cloudina shells: Complex predator-prey dynamics in the terminal Proterozoic. Palaios, 18: 454459.
Mehl J. 1984. Radula und Fangarme bei Michelinoceras sp. aus dem Silur von Bolivien. Paläontologische Zeitschrift, 58:211229.
Mischor B. and Märkel K. 1984. Histology and regeneration of the radula of Pomacea bridgesi (Gastropoda, Prosobranchia). Zoomorphology, 104: 4266.
Novack-Gottshall P. M. and Miller A. I. 2003. Comparative geographic and environmental diversity dynamics of gastropods and bivalves during the Ordovician Radiation. Paleobiology, 29:576604.
Passamaneck Y. J., Schander C., and Halanych K. M. 2004. Investigation of molluscan phylogeny using large-subunit and small-subunit nuclear rRNA sequences. Molecular Phylogenetics and Evolution, 32:2538.
Peterson K. J. and Eernisse D. J. 2001. Animal phylogeny and the ancestry of bilaterians: Inferences from morphology and 18S rDNA gene sequences. Evolution and Development, 3:170205.
Pojeta J Jr., Eernisse D. J., Hoare R. D., and Henderson M. D. 2003. Echinochiton dufoei: A new spiny Ordovician chiton. Journal of Paleontology, 77:646654.
Runham N. W. and Thornton P. R. 1967. Mechanical wear of the gastropod radula: A scanning electron microscope study. Journal of Zoology, 153: 445452.
Salvini-Plawen L. v. 1981. The mollusan digestive system in evolution. Malacologia, 21:371401.
Salvini-Plawen L. v. 1985. Early evolution and the primitive groups, p. 59150. In Trueman E. R. and Clarke M. R. (eds.), The Mollusca. Volume 10, Evolution. Academic Press, Orlando.
Salvini-Plawen L. v. 1988. The structure and function of molluscan digestive systems, p. 301379. In Trueman E. R. and Clarke M. R. (eds.), The Mollusca. Volume 11, Form and Function. Academic Press, London.
Scheltema A. H. 1981. Comparative morphology of the radulae and alimentary tracts in the Aplacophora. Malacologia, 20:361383.
Scheltema A. H. 1993. Aplacophora as progenetic aculiferans and the coelomate origin of mollusks as sister taxon of Sipuncula. Biological Bulletin, 184:5778.
Scheltema A. H. 1999. Two solenogaster molluscs, Ocheyoherpia tracia n.sp. from Macquarie Island and Tegulaherpia tasmanica Salvini-Plawen from Bass Strait (Aplacophora: Neomeniomorpha). Records of the Australian Museum, 51:2331.
Scheltema A. H. and Ivanov D. L. 2002. An aplacophoran postlarva with iterated dorsal groups of spicules and skeletal similarities to Paleozoic fossils. Invertebrate Biology, 121:110.
Scheltema A. H., Kerth K., and Kuzirian A. M. 2003. Original molluscan radula: Comparisons among aplacophora, polyplacophora, gastropoda, and the Cambrian fossil Wiwaxia corrugata. Journal of Morphology, 257: 219245.
Scheltema A. H. and Schander C. 2000. Discrimination and phylogeny of solenogaster species through the morphology of hard parts (Mollusca, Aplacophora, Neomeniomorpha). Biological Bulletin, 198:121151.
Seilacher A., Grazhdankin D., and Legouta A. 2003. Ediacaran biota: The dawn of animal life in the shadow of giant protists. Paleontological Research, 7:4354.
Sirenko B. I. 1997. The importance of the development of articulamentum for taxonomy of chitons (Mollusca, Polyplacophora). Ruthenica, 7:124.
Solem A. and Richardson E. S. 1975. Paleocadmus, a nautiloid cephalopod radula from the Pennsylvanian Francis Creek Shale of Illinois. The Veliger, 17:233242.
Stankiewicz B. A., Briggs D. E. G., Evershed R. P., Flannery M. B., and Wuttke M. 1997. Preservation of chitin in 25-million-year-old-fossils. Science, 276:15411543.
Steiner G. and Salvini-Plawen L. 2001. Acaenoplax—polychaete or mollusc? Nature, 414:601602.
Strother P. K., Wood G. D., Taylor W. A., and Beck J. H. 2004. Middle Cambrian cryptospores and the origin of land plants. Association of Australasian Palaeontologists, Memoirs, 29:99113.
Sutton M. D., Briggs D. E. G., Siveter D. J., and Siveter D. J. 2004. Computer reconstruction and analysis of the vermiform mollusc Acaenoplax hayae from the Herefordshire Lagerstätte (Silurian, England) and implications for molluscan phylogeny. Palaeontology, 47:293318.
Sutton M. D., Briggs D. E. G., Siveter D. J., and Siveter D. J. 2006. Fossilized soft tissues in a Silurian platyceratid gastropod. Proceedings of the Royal Society B, 273:10391044.
Szaniawski H. 2002. New evidence for the protoconodont origin of chaetognaths. Acta Palaeontologica Polonica, 473:405419.
Tzetlin A. B. 2004. Ultrastructural study of the jaw structures in two species of Ampharetidae (Annelida: Polychaeta). Acta Zoologica, 85:171180.
Tzetlin A. and Purschke G. 2005. Pharynx and intestine. In Bartolomaeus T. and Purschke G. (eds.), Morphology, Molecules, Evolution and Phylogeny in Polychaeta and Related Taxa. Hydrobiologia, 535/536:199225.
Vannier J., Steiner M., Renvoisé E., Hu S.-X., and Casanova J.-P. 2007. Early Cambrian origin of modern food webs: Evidence from predator arrow worms. Proceedings of the Royal Society B, 274:627633.
Vendrasco M. J., Wood T. E., and Runnegar B. N. 2004. Articulated Palaeozoic fossil with 17 plates greatly expands disparity of early chitons. Nature, 429:288291.
Vinther J. and Nielsen C. 2005. The early Cambrian Halkieria is a mollusc. Zoologica Scripta, 34:8189.
Voltzow J. 1994. Gastropoda: Prosobranchia, p. 111252. In Harrison F. W. and Kohn A. J. (eds.), Microscopic Anatomy of Invertebrates. Volume 5, Mollusca I. Wiley-Liss, New York.
Whittington H. W. and Briggs D. E. G. 1985. The largest Cambrian animal, Anomalocaris, Burgess Shale, British Columbia. Philosophical Transactions of the Royal Society of London B, 311:1192.
Yochelson E. L. and Richardson E. S. Jr. 1979. Polyplacophoran molluscs of the Essex Fauna (Middle Pennsylvanian, Illinois), p. 321332. In Nitecki M. H. (ed.), Mazon Creek Fossils. Academic Press, New York.
Zhuravlev A. Y. and Wood R. A. 1996. Anoxia as the cause of the mid-early Cambrian (Botomian) extinction event. Geology, 24:311314.
Recommend this journal

Email your librarian or administrator to recommend adding this journal to your organisation's collection.

Journal of Paleontology
  • ISSN: 0022-3360
  • EISSN: 1937-2337
  • URL: /core/journals/journal-of-paleontology
Please enter your name
Please enter a valid email address
Who would you like to send this to? *


Altmetric attention score

Full text views

Total number of HTML views: 0
Total number of PDF views: 3 *
Loading metrics...

Abstract views

Total abstract views: 80 *
Loading metrics...

* Views captured on Cambridge Core between September 2016 - 23rd October 2017. This data will be updated every 24 hours.