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Shell structure of the Galapagos Rift limpet Neomphalus fretterae McLean 1981, with notes on muscle scars and insertions

by: Batten, Roger Lyman

Publication date: 1984

Topics: Neomphalus fretterae, Limpets, Anatomy, Mollusks, Living fossils, Limpets -- Pacific Ocean -- Anatomy, Limpets -- Galapagos Islands -- Anatomy, Limpets -- Anatomy, Mollusks -- Pacific Ocean -- Anatomy, Mollusks -- Galapagos Islands -- Anatomy, Mollusks -- Anatomy, Mollusks, Anatomy, Living fossils

Publisher: New York, N.Y. : American Museum of Natural History

Collection: americanmuseumnaturalhistory; biodiversity

Contributor: American Museum of Natural History Library

Language: English

Rights: http://biodiversitylibrary.org/permissions

Rights-holder: American Museum of Natural History Library

Volume: no. 2776

13 p. : 26 cm

"The principal shell layers of Neomphalus fretterae McLean, 1981, are an inner concentric crossed-lamellar and an outer complex crossed-lamellar layer. The protoconch is unusual in being composed of four layers rather than one or two as in most other gastropods. The narrow, high-angled crossed-lamellae of the inner principal layer are nearly identical with those of advanced mesogastropods, rather than the broader, low-angled archeogastropod crossed-lamellae. This, along with shell shape, ornament, and the presence of a muscle platform suggests a closer relationship with the mesogastropod limpets than with the archeogastropods. Muscle attachment is by direct muscle fiber insertion, forming tubules in the shell, and also by myo-adhesive epithelial cells which may form a myostracal layer. Based on the multiple layers found in the protoconch, I speculate on the possibility that the larval stage may have remained planktonic for an extended period"--P. [1]

Title from caption

"January 30, 1984."

Includes bibliographical references (p. 12-13)

Abstract: 'The principal shell layers of Neomphalus fretterae McLean, 1981, are an inner concentric crossed-lamellar and an outer complex crossed-lamellar layer. The protoconch is unusual in being composed of four layers rather than one or two as in most other gastropods. The narrow, high-angled crossed-lamellae of the inner principal layer are nearly identical with those of advanced mesogastropods, rather than the broader, low-angled archeogastropod crossed-lamellae. This, along with shell shape, ornament, and the presence of a muscle platform suggests a closer relationship with the mesogastropod limpets than with the archeogastropods. Muscle attachment is by direct muscle fiber insertion, forming tubules in the shell, and also by myo-adhesive epithelial cells which may form a myostracal layer. Based on the multiple layers found in the protoconch, I speculate on the possibility that the larval stage may have remained planktonic for an extended period'--P. [1].