the embryonic development of the central american wandering spider cupiennius salei中美洲的胚胎发育蜘蛛cupiennius salei.pdf

The embryonic development of the central American wandering spider Cupiennius salei Wolff and Hilbrant Wolff and Hilbrant Frontiers in Zoology 2011, 8:15 /content/8/1/15 (14 June 2011) Wolff and Hilbrant Frontiers in Zoology 2011, 8:15 /content/8/1/15 RESEARCH Open Access The embryonic development of the central American wandering spider Cupiennius salei Carsten Wolff1*† and Maarten Hilbrant2,3*† Abstract Background: The spider Cupiennius salei (Keyserling 1877) has become an important study organism in evolutionary and developmental biology. However, the available staging system for its embryonic development is difficult to apply to modern studies, with strong bias towards the earliest developmental stages. Furthermore, important embryonic events are poorly understood. We address these problems, providing a new description of the embryonic development of C. salei. The paper also discusses various observations that will improve our understanding of spider development. Results: Conspicuous developmental events were used to define numbered stages 1 to 21. Stages 1 to 9 follow the existing staging system for the spider Achaearanea tepidariorum, and stages 10 to 21 provide a high-resolution description of later development. Live-embryo imaging shows cell movements during the earliest formation of embryonic tissue in C. salei. The imaging procedure also elucidates the encircling border between the cell-dense embryo hemisphere and the hemisphere with much lower cell density (a structure termed ‘equator’ in earlier studies). This border results from subsurface migration of primordial mesendodermal cells from their invagination site at the blastopore. Furthermore, our detailed success