Hostname: page-component-586b7cd67f-l7hp2 Total loading time: 0 Render date: 2024-11-23T19:06:20.189Z Has data issue: false hasContentIssue false
  • English
  • Français

Morphological channeling by structural constraint: convergence in styles of dwarfing and gigantism in Cerion, with a description of two new fossil species and a report on the discovery of the largest Cerion

Published online by Cambridge University Press:  08 February 2016

Stephen Jay Gould
Stephen Jay Gould*
Affiliation:
Museum of Comparative Zoology, Harvard University, Cambridge, Massachusetts 02138
Get access Rights & Permissions [Opens in a new window]

Abstract

A survey of all Cerion taxa and geographic variants reveals that a distinctive shape—a narrowly spired “smokestack” shell more than three times higher than wide—occurs only in dwarfs and giants and never in the much more common populations of normal size. The smokestack shape evolved once in giants (in the newly described species C. excelsior from Great Inagua and Mayaguana—the largest of all Cerion), but at least seven and probably eight times independently in dwarfs. A study of complex allometric patterns in Cerion's ontogeny, and of covariance sets in growth, indicates that smokestacks can easily evolve in dwarfs and giants by the common route of relative increase in whorl number during an allometric phase that adds height but no width to the shell. (Giants simply add more whorls to a shell with whorls of normal size; dwarfs grow a normal number of whorls in a shell with small whorls and reduced maximum width.) This pathway is not open to Cerion of normal size, and the restriction of smokestacks to both extremes of the size range records a channel set by Cerion's invariant allometries and the geometry of spiral growth in general, not an immediate adaptation conferring special advantages via the elevated spire itself.

Type
Research Article
Information
Paleobiology , Volume 10 , Issue 2 , Spring 1984 , pp. 172 - 194
Copyright
Copyright © The Paleontological Society 

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

Literature Cited

Andrews, H. E. III. 1971. Turritella mortoni (Gastropoda) and biostratigraphy of the Aquia Formation (Paleocene) of Maryland and Virginia. Ph.D. thesis, Harvard Univ. 207 pp.Google Scholar
Boettger, C. R. 1952. Grössenwachstum und Geschlechtsreife bei Schnecken und pathologischer Riesenwuchs als Folge einer gestörten Wechselwirkung beider Faktoren. Zool. Anz. 17(suppl.):468–487.Google Scholar
Cain, A. J. 1977. Variation in the spire index of some coiled gastropod shells and its evolutionary significance. Phil. Trans. R. Soc. Lond. B. 277:377–428.Google ScholarPubMed
Cain, A. J. 1978. Variation of terrestrial gastropods in the Philippines in relation to shell shape and size. J. Conch. Lond. 29:239–245.Google Scholar
Cain, A. J. 1980. Whorl number, shape, and size of shell in some pulmonate faunas. J. Conch. Lond. 30:209–221.Google Scholar
Clench, W. J. 1937. Three new species of Cerion from Long Island, Bahamas. Nautilus. 51:19–23.Google Scholar
Clench, W. J. 1948. Two new species of Cerion from Cuba and New Providence, Bahamas. Rev. Soc. Malacol. “Carlos de la Torre.” 6:49–51.Google Scholar
Clench, W. J. 1957. A catalogue of the Cerionidae (Mollusca: Pulmonata). Bull. Mus. Comp. Zool. 116:121–169.Google Scholar
Clench, W. J. and Aguayo, C. G. 1946. Una interesante especie nueva del genero Cerion. Rev. Soc. Malacol. “Carlos de la Torre.” 4:85–87.Google Scholar
Dall, W. H. 1915. A monograph of the molluscan fauna of the Orthaulax pugnax zone of the Oligocene of Tampa, Florida. U.S. Nat. Mus. Bull. 90. 173 pp.Google Scholar
Goldschmidt, R. 1940. The Material Basis of Evolution. 436 pp. Yale Univ. Press (reprinted 1982 with introduction byGould, S. J.); New Haven.Google Scholar
Gould, S. J. 1969. An evolutionary microcosm: Pleistocene and Recent history of the land snail P. (Poecilozonites) in Bermuda. Bull. Mus. Comp. Zool. 138:407–532.Google Scholar
Gould, S. J. 1977. Ontogeny and Phylogeny. 506 pp. Belknap Press; Cambridge, Mass.Google Scholar
Gould, S. J. 1983. Hen's Teeth and Horse's Toes. 413 pp. (See essay 10, A hearing for Vavilov, pp. 134–144). Norton; New York.Google Scholar
Gould, S. J. 1984. Covariance sets and ordered geographic variation in Cerion from Aruba, Bonaire and Curaçao: a way of studying nonadaptation. Syst. Zool. 33:217–237.CrossRefGoogle Scholar
Gould, S. J.In prep. a. A developmental constraint in Cerion..Google Scholar
Gould, S. J.In prep. b. Probing the limits of a covariance pattern: the case of Cerion disforme..Google Scholar
Gould, S. J. and Paull, C. 1977. Natural history of Cerion. VII. Geographic variation of Cerion (Mollusca: Pulmonata) from the eastern end of its range (Hispaniola to the Virgin Islands): coherent patterns and taxonomic simplification. Mus. Comp. Zool. Breviora 445. 24 pp.Google Scholar
Gould, S. J. and Vrba, E. S. 1982. Exaptation—a missing term in the science of form. Paleobiology. 8(1):4–15.CrossRefGoogle Scholar
Gould, S. J. and Woodruff, D. S. 1978. Natural history of Cerion. VIII. Little Bahama Bank—a revision based on genetics, morphometrics, and geographic distribution. Bull. Mus. Comp. Zool. 148(8):371–415.Google Scholar
Gould, S. J. and Woodruff, D. S.In press. The natural history of Cerion. XVII. New Providence Island—a radical revision of Cerions highest recorded diversity. Bull. Mus. Comp. Zool.Google Scholar
Gould, S. J., Woodruff, D. S., and Martin, J. P. 1974. Genetics and morphometries of Cerion at Pongo Carpet: a new systematic approach to this enigmatic land snail. Syst. Zool. 23(4):518–535.CrossRefGoogle Scholar
Hummelinck, P. W. 1980. Caribbean land molluscs. Cerion in the Cayman Islands. Stud. Fauna Curaçao and Other Caribbean Is. 61:1–67.Google Scholar
Huxley, J. S. 1932. Problems of Relative Growth. 276 pp. MacVeagh; London.Google Scholar
Raup, D. M. 1966. Geometric analysis of shell coiling: general problems. J. Paleontol. 40:1178–1190.Google Scholar
Thompson, D'Arcy W. 1942. On Growth and Form. 1,116 pp. Cambridge Univ. Press; Cambridge.Google Scholar
Vavilov, N. I. 1922. The law of homologous series in variation. J. Genet. 12:47–89.CrossRefGoogle Scholar
Woodruff, D. S. and Gould, S. J. 1980. Geographic differentiation and speciation in Cerion—a preliminary discussion of patterns and processes. Biol. J. Linn. Soc. 14:389–416.CrossRefGoogle Scholar
Williamson, P. G.In press. Comments on the distribution of Cain's parameters H (shell height), D (shell width), and W (whorl number) in gastropods.Google Scholar