Ultrastructure of eggshell and embryological development of Salvator merianae (Squamata : Teiidae)

Abstract

The objective of this study was to characterize the external morphology of Salvator meriane embryos in different stages of embryonic development and

establish a relationship with the ultrastructure of the shell from oviductal transit to hatching. A total of 120 embryos were analyzed to describe their external

morphology, and 78 eggs were used for the analysis of the shell. For embryonic development, the series was established according to the total length of the body. We established 40 embryonic stages from the primitive streak. In the early stages, the external morphological features are the C-shaped body, the maxillary, and mandibular fusion processes with the frontal process and the fusion of the forelimb with the digital plate. In the middle stages, the eyelid appears, and there are claws on the toes, cornification of fingers, and the onset of pigmentation. The last stage of embryonic development is characterized by the beginning of the formation of the scales, appear the toenails, and finalize

the entire pigmentation. Regarding the relationship that exists with the ultrastructure of the egg during development, it was possible to observe a marked

change in the composition of the shell and well-marked compaction during

embryonic development, which may be related to the transport of calcium during embryonic ossification. Our results allowed us to show the complete

sequence of embryonic development, determining the laying stage for this species. It was possible to establish a relationship with the ultrastructure of the

eggshell from the oviductal transit to the moment of hatching.