Structure of shells from eggs of kinosternid turtles

Journal of Morphology
M J PackardJohn B Iverson

Abstract

Shells from eggs of five species of kinosternid turtle (Sternotherus minor, Kinosternon flavescens, K. baurii, K. Hirtipes, and K. alamosae) were examined with light and scanning electron microscopy. Except for possible differences among species in thickness of eggshells, structure of shells from all eggs was similiar. In general, kinosternid turtles lay eggs having a rigid calcareous layer composed of calcium carbonate in the form of aragonite. The calcareous layer is organized into individual shell units with needlelike crystallites radiating from a common center. Most of the thickness of the eggshell is attributable to the calcareous layer, with the fibrous shell membrane comprising only a small fraction of shell thickness. Pores are found in the calcareous layer, but they are not numereous. The outer surface of the eggshells is sculptured and may have a thick, organic layer in places. The outer surface of the shell membrane of decalcified eggshells is studded with spherical cores which presumably nucleate growth of shell units during shell formation. The shell membrane detaches from eggs incubated to hatching, carrying with it remnants of the calcareous layer. Such changes in shell structure presumably reflect withdrawal of...Continue Reading

References

Jan 1, 1969·Zeitschrift für Zellforschung und mikroskopische Anatomie·R Bellairs, A Boyde
Jan 1, 1979·Journal of Morphology·Mary J Packard, Gary C Packard

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Citations

Apr 29, 2011·Microscopy and Microanalysis : the Official Journal of Microscopy Society of America, Microbeam Analysis Society, Microscopical Society of Canada·S N Al-BahryI Al-Amri
Nov 1, 1996·Journal of Morphology·Alison CreeKaren Reader
May 8, 2013·Zoological Science·Satoshi KusudaNorio Yoshizaki
Aug 1, 1988·Journal of Morphology·Mary J PackardMarta Vos
Jul 1, 1984·Journal of Morphology·Mary J PackardGary C Packard
May 16, 2021·Journal of Morphology·J Matthias StarckDaniel G Blackburn
Jan 30, 2010·Comparative Biochemistry and Physiology. Part B, Biochemistry & Molecular Biology·Shigeki YasumasuNorio Yoshizaki

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