Hostname: page-component-586b7cd67f-tf8b9 Total loading time: 0 Render date: 2024-11-27T14:42:22.588Z Has data issue: false hasContentIssue false
  • English
  • Français

Paedomorphosis and cryptogenesis in trilobites

Published online by Cambridge University Press:  01 May 2009

H. B. Whittington
H. B. Whittington
Affiliation:
Sedgwick Museum, Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EQ
Get access Rights & Permissions [Opens in a new window]

Summary

Stubblefield suggested that proparian trilobites may have arisen by paedomorphosis. Examples of the role of paedomorphosis in the evolution of species and of particular organs are reviewed. The cryptogenetic renewal of trilobites after the Cambrian resulted in distinctive major taxa, but their relationships to each other and to older groups remain unsolved. Similarities between early developmental stages should be re-assessed as a possible guide to relationships. The early Upper Cambrian, type species of the proparian Schmalenseeia is re-described. It was small, possibly world-wide in distribution, the exoskeleton thin, the parts not articulated, apparently forming a more or less rigid shield. It may have been a paedomorphic, planktic species, but its origin and relationships are obscure.

Type
Articles
Information
Geological Magazine , Volume 118 , Issue 6 , November 1981 , pp. 591 - 602
Copyright
Copyright © Cambridge University Press 1981

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Bergström, J. 1973. Organisation, life and systematics of trilobites. Fossils & Strata 2, 1–69.CrossRefGoogle Scholar
Chatterton, B. D. E. 1971. Taxonomy and ontogeny of Siluro-Devonian trilobites from near Yass, New South Wales. Palaeontographica A, 137, 1–108.Google Scholar
Clarkson, E. N. K. 1975. The evolution of the eye in trilobites. Fossils & Strata 4, 7–31.CrossRefGoogle Scholar
De Beer, G. 1930. Embryology and Evolution. Oxford: Clarendon Press.Google Scholar
Evitt, W. R. & Tripp, R. P. 1977. Silicified Middle Ordovician trilobites from the families Encrinuridae and Staurocephalidae. Palaeontographica A, 157, 109–174.Google Scholar
Fortey, R. A. 1974. The Ordovician trilobites of Spitsbergen. I. Olenidae. Norsk Polarinst. Skr. 160, 1–129.Google Scholar
Fortey, R. A. 1975. The Ordovician trilobites of Spitsbergen. II. Asaphidae, Nileidae, Raphiophoridae and Telephinidae of the Valhallfonna Formation. Norsk Polarinst. Skr. 162, 1–207.Google Scholar
Fortey, R. A. 1980. The Ordovician trilobites of Spitsbergen. III. Remaining trilobites of the Valhallfonna Formation. Norsk Polarinst. Skr. 171, 1–163.Google Scholar
Fortey, R. A. & Owens, R. M. 1975. Proetida – a new order of trilobites. Fossils and Strata 4, 227–39.CrossRefGoogle Scholar
Fortey, R. A. & Owens, R. M. 1979. Enrollment in the classification of trilobites. Lethaia 12, 219–226.CrossRefGoogle Scholar
Fortey, R. A. & Rushton, A. W. A. 1980: Acanthopleurella Groom 1902: origin and life-habits of a miniature trilobite. Bull. Br. Mus. Nat. Hist. (Geol.) 33, 78–79.Google Scholar
Gould, S. J. 1977. Ontogeny and Phylogeny. Cambridge, Mass. and London: Harvard University Press.Google Scholar
Hallam, A. (editor) 1977. Patterns of Evolution, as illustrated by the Fossil Record. Develop. Palaeo. Strat. 5. Amsterdam, Oxford, New York: Elsevier.Google Scholar
Hu, C. H. 1971. Ontogeny and sexual dimorphism of Lower Palaeozoic Trilobita. Palaeontogr. Americana, 7 (44), 31–155.Google Scholar
Hughes, C. P., Ingham, J. K. & Addison, R. 1975. The morphology, classification and evolution of the Trinucleidae (Trilobita). Phil. Trans. R. Soc. Lond. B 272, 537–604.Google Scholar
Hutchinson, R. D. 1962. Cambrian stratigraphy and trilobite faunas of southeastern Newfoundland. Bull. geol. Surv. Can. 88.Google Scholar
Jago, J. B. 1972. Two new Cambrian trilobites from Tasmania. Palaeontology 15, 226–37.Google Scholar
Jell, P. A. 1975. Australian Middle Cambrian eodiscoids with a review of the superfamily. Palaeontographica A, 150, 1–97.Google Scholar
Ludvigsen, R. 1979. The Ordovician trilobite Pseudogygites Kobayashi in eastern and arctic North America. Life Sci. Contrib., R. Ontario Mus. 120, 1–41.Google Scholar
McNamara, K. J. 1978. Paedomorphosis in Scottish olenellid trilobites (early Cambrian). Palaeontology. 21, 635–55.Google Scholar
Moberg, J. C. 1903. Schmalenseeia amphionura, en ny trilobit-typ. Geol. Foren. Förhandl. 25, 93–102.CrossRefGoogle Scholar
Moore, R. C. (editor), 1959. Treatise on Invertebrate Paleontology, Pt. O, Arthropoda l. Lawrence, Kansas: Univ. Kansas and Geol. Soc. Amer.Google Scholar
Palmer, A. R. 1957. Ontogenetic development of two olenellid trilobites. J. Paleont. 31, 105–28.Google Scholar
Palmer, A. R. 1962. Comparative ontogeny of some opisthoparian, gonatoparian, and proparian Upper Cambrian trilobites. J. Paleont. 36, 87–96.Google Scholar
Palmer, A. R. & Halley, R. B. 1979. Physical stratigraphy and trilobite biostratigraphy of the Carrara Formation (Lower and Middle Cambrian) in the southern Great Basin. Prof. Pap. U.S. geol. Surv. 1047.Google Scholar
Rasetti, F. 1951. Middle Cambrian stratigraphy and faunas of the Canadian Rocky Mountains. Smithson. Misc. Collns. 116.Google Scholar
Rasetti, F. 1972. Cambrian trilobite faunas of Sardinia. Atti della Accademia Nazionale dei Lincei, Mem. Ser. 8, vol. XI, 1–100.Google Scholar
Robison, R. A. 1967. Ontogeny of Bathyuriscus fimbriatus and its bearing on affinities of corynexochoid trilobites. J. Paleont. 41, 213–221.Google Scholar
Robison, R. A. & Campbell, D. P. 1974. A Cambrian corynexochoid trilobite with only two thoracic segments. Lethaia 7, 273–82.CrossRefGoogle Scholar
Rushton, A. W. A. 1978. Fossils from the Middle–Upper Cambrian transition in the Nuneaton district. Palaeontology 21, 245–83.Google Scholar
Sdzuy, K. 1979. Two rare trilobites from the Tremadoc Leimuz Shales, Germany. Alcheringa 3, 63–72.CrossRefGoogle Scholar
Sepkoski, J. J. 1979. A kinetic model of Phanerozoic diversity. II. Early Phanerozoic families and multiple equilibria. Paleobiology 5, 222–51.CrossRefGoogle Scholar
Stubblefield, C. J. 1926. Notes on the development of a trilobite, Shumardia pusilla (Sars). J. Linn. Soc. (Zool.) 36, 345–72.CrossRefGoogle Scholar
Stubblefield, C. J. 1936. Cephalic sutures and their bearing on current classifications of trilobites. Biol. Rev. 11, 407–40.CrossRefGoogle Scholar
Stubblefield, C. J. 1959. Evolution in trilobites. Q. Jl. geol. Soc. Lond. 115, 145–62.CrossRefGoogle Scholar
Walcott, C. D. 1908. Cambrian trilobites. Smithson. Misc. Collns. 53, 13–52.Google Scholar
Westergaard, A. H. 1922. Sveriges Olenidskiffer. Sverig. geol. Unders., Ser. Ca, no. 18.Google Scholar
Westergaard, A. H. 1936. Paradoxides oelandicus beds of Öland. Sverig. geol. Unders., Ser. C., no. 394, 1–66.Google Scholar
Westergaard, A. H. 1948. Non-agnostidean trilobites of the Middle Cambrian of Sweden. Sverig. geol. Unders., Ser. C, no. 498, 1–32.Google Scholar
Whittington, H. B. 1954. Arthropoda: Trilobita. In Status of Invertebrate Paleontology, 1953 (ed. Kummel, B.) Bull. Mus. Comp. Zool. (Harvard) 112, 193–200.Google Scholar
Whittington, H. B. 1956. Beecher's lichid protaspis and Acanthopyge consanguinea (Trilobita). J. Paleont. 30, 1200–4.Google Scholar
Whittington, H. B. 1966. Phylogeny and distribution of Ordovician trilobites. J. Paleont. 40, 696–737.Google Scholar
Whittington, H. B. 1977. The Middle Cambrian trilobite Naraoia, Burgess Shale, British Columbia. Phil. Trans. R. Soc. Lond. B 280, 409–43.Google Scholar
Whittington, H. B. & Evitt, W. R. 1954. Silicified Middle Ordovician trilobites. Mem. geol. Soc. Amer. 59, 1–137.Google Scholar
Whittington, H. B. & Hughes, C. P. 1974. Geography and faunal provinces in the Tremadoc Epoch. In Paleogeographic Provinces and Provinciality (ed. Ross, C. A.). S.E.P.M. Spec. Publ. 21, 203–18.CrossRefGoogle Scholar