Post-embryonic tail development through molting of the freshwater shrimpNeocaridina denticulata

Abstract

Background: Understanding postembryonic morphogenesis through molting in arthropods has recently become a focus of developmental biology. The hierarchical mechanisms of epithelial sheet folds play a significant role in this process. Drosophila is a well-studied model for holometabolous insects, with extensive research on imaginal disc growth. While developmental processes in other arthropods have been described, live imaging of morphological changes is challenging due to the macroscopic movements and hard cuticles. Neocaridina denticulata, a crustacean, presents unique tail morphogenesis through molting, which makes it the potential model. This study investigated the development of the tail in Neocaridina denticulata through histological analysis and in vivo live imaging using fluorescent probes. This study also performed long-read sequencing of the whole genome for future genetic tools. Results: The tail of Neocaridina was found to undergo two major changes with the first ecdysis. Firstly, the branches of the uropods are cleared, and secondly, the telson undergoes convergent elongation. Cross-sectional analysis revealed that uropod and telson branching occurs immediately after hatching in the form of cuticle branching. The surface structure of the developmental tail suggested that telson elongation is achieved by the extension of anisotropic furrows in the cuticle during ecdysis. Anisotropy of cuticle furrows was associated with the epithelial cell shape, and the anisotropy of cell shape was found to occur during development from post-hatching. We also established an in vivo live imaging system with UV-LED resin and detected the changes of tail development over time. in vivo live imaging analysis revealed that telson contraction occurs gradually prior to ecdysis. Furthermore, we have also provided a draft genome of Neocaridina. Conclusion: Neocaridina denticulata is a valuable model for studying morphogenesis in arthropods through molting. The tail undergoes complex changes involving cuticle branching, anisotropic furrows, and cellular dynamics. in vivo live imaging system provides insights into the developmental process, and the draft genome enhances the potential for genetic tools in future studies. This research contributes to the understanding of arthropod morphogenesis and provides a foundation for further developmental and cytological investigations in Neocaridina.