The Early Cambrian organism Olivooides is known from both embryonic and post-embryonic stages and, consequently, it has the potential to yield vital insights into developmental evolution at the time that animal body plans were established. However, this potential can only be realized if the phylogenetic relationships of Olivooides can be constrained. The affinities of Olivooides have proved con...

Introdouction: Age estimation is an important issue in forensics, particularly for treatment planning and determining patients’ rights. Radiographic evaluation of the third molar developmental stage is a significant criterion for age estimation. The pattern of tooth development is largely heritable and varies from race to race. The objective of this study was to radiographically examine and com...

A fundamental question in developmental biology relates to the connection between morphological stages and their underlying molecular activity. Here we demonstrate that, at the molecular level, embryonic development in five Caenorhabditis species proceeds through two distinct milestones in which the transcriptome is resistant to differences in species-specific developmental timings. By comparin...

Metazoan life cycles can be complex in different ways. A number of diverse phenotypes and reproductive events can sequentially occur along the cycle, and at certain stages a variety of developmental and reproductive options can be available to the animal, the choice among which depends on a combination of organismal and environmental conditions. We hypothesize that a diversity of phenotypes arr...

Sea Urchin is one of the most useful tools in developmental biology studies because this organism has the simplest kind of developmental stages. We aimed to determine developmental stages and timetable of Echinometra mathaei embryo (the species of Persian Gulf). The spawning of E. mathaei was induced by 0.5M KCl injection (1ml) into the coelomic cavity. After fertilization, embryos were placed ...