\u201cIntracascaral space\u201d an eggshell structure of Caiman latirostris eggs

Mila V Piazza,Carlos I Piña,Melina S Simoncini,Mariela S Fernández,Pamela M L Leiva

doi:10.1038/s41598-021-85113-9

Abstract

In recent decades, eggshells of eggs from large-bodied reptiles have been studied by many researchers, to describe the eggshell, to compare them to extinct lineages that once inhabited our planet and also to understand how the egg provides the embryo specific conditions during incubation. In previous studies we described and characterized normal and pathologic Caiman latirostris eggshells; we also evaluated how the eggshell changes during incubation. In a study relating temperature variation and eggshell structures of successful eggs, we observed empty structures not previously described that we termed “intracascaral space”. The aim of this study is to describe this structure of C. latirostris eggshells. We hypothesize about the possible functions which it would perform during incubation and for development of the embryos.

Highlights

In recent decades, eggshells of eggs from large-bodied reptiles have been studied by many researchers, to describe the eggshell, to compare them to extinct lineages that once inhabited our planet and to understand how the egg provides the embryo specific conditions during incubation
Caiman latirostris eggs may vary in calcification, being heavily or slightly c alcified[6], and this depends on the food resources available to females[8], and whether they live in the wild or in captivity
Studies on Alligator mississippiensis reveal that during the third week of incubation there is a reduction in the small calcium crystals in eggshell, which appear to be mobilized in the embryo calcification[17]

Summary

Introduction

Eggshells of eggs from large-bodied reptiles have been studied by many researchers, to describe the eggshell, to compare them to extinct lineages that once inhabited our planet and to understand how the egg provides the embryo specific conditions during incubation. Nest material performs important functions such as: mechanical protection, buffering sudden changes in environmental temperature These conditions produce a suitable environment for the development of a microflora/fauna that results in fermentation of organic material, which will transfer heat to the developing eggs. Microorganisms produce metabolic acids as a fermentation product of nest vegetation which in combination with carbonic acid (formed by the hydration of the expired CO2) dissolves calcite crystals forming craters[12] Temperature could be another external factor that would modify the calcareous layer of eggshells, by affecting composition and density of microorganisms in the nest material, which could increase or decrease transferred heat to embryo during incubation, resulting in an increase or decrease in embryo metabolism. The objective of this work was to observe how constant and fluctuating temperatures affect eggshell structures at the end of incubation

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Conclusion