Shell microstructure of gastropods from Lake Tanganyika, Africa: Adaptation, convergent evolution, and escalation

Kelly West, Andrew Cohen

Research output: Contribution to journalArticle

51 Citations (Scopus)

Abstract

Gastropod shells from Lake Tanganyika, with their heavy calcification, coarse noded ribbing, spines, apertural lip thickening and repair scars, resemble marine shells more closely than they resemble other lacustrine shells. This convergence between Tanganyikan and marine gastropod shells, however, is not just superficial. Scanning electron microscope (SEM) studies reveal that the Tanganyikan shells are primarily layers of crossed-lamellar crystal architecture (that is, needle-like aragonite crystals arranged into laths that are packed into sheets such that the aragonite needles of adjacent laths are never parallel). The number of crossed-lamellar layers can vary from one to four between different Tanganyikan gastropod species. In species with two or more crossed-lamellar layers, the orientation of the lamellae is offset by approximately 90° between the different layers. The number of crossed-lamellar layers in the shell wall is positively correlated with shell strength and with predation resistance. Three and four crossed-lamellar layers in the shell wall evolved several times independently within the endemic thiarid gastropod radiation in Lake Tanganyika. Repeated origins of three and four crossed-lamellar layers suggest that they may be specific adaptations by Tanganyikan gastropods to strengthen their shells as a defense against shell-crushing predators.

Original languageEnglish (US)
Pages (from-to)672-681
Number of pages10
JournalEvolution
Volume50
Issue number2
StatePublished - Apr 1996

Fingerprint

Lake Tanganyika
convergent evolution
Gastropoda
Tanzania
shell (molluscs)
Lakes
gastropod
microstructure
shell
lake
Calcium Carbonate
Needles
aragonite
Lip
Cicatrix
crystals
Spine
Africa
Electrons
Radiation

Keywords

  • Adaptation
  • Escalation
  • Lake Tanganyika
  • Predation resistance
  • Shell microstructure
  • Shell strength
  • Thiarid gastropods

ASJC Scopus subject areas

  • Agricultural and Biological Sciences(all)
  • Agricultural and Biological Sciences (miscellaneous)
  • Ecology, Evolution, Behavior and Systematics
  • Genetics
  • Ecology
  • Genetics(clinical)

Cite this

Shell microstructure of gastropods from Lake Tanganyika, Africa : Adaptation, convergent evolution, and escalation. / West, Kelly; Cohen, Andrew.

In: Evolution, Vol. 50, No. 2, 04.1996, p. 672-681.

Research output: Contribution to journalArticle

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