TY - JOUR AU - Helm, Rebecca R. AU - Tiozzo, Stefano AU - Lilley, Martin K. S. AU - Lombard, Fabien AU - Dunn, Casey W. PY - 2015 DA - 2015/04/17 TI - Comparative muscle development of scyphozoan jellyfish with simple and complex life cycles JO - EvoDevo SP - 11 VL - 6 IS - 1 AB - Simple life cycles arise from complex life cycles when one or more developmental stages are lost. This raises a fundamental question - how can an intermediate stage, such as a larva, be removed, and development still produce a normal adult? To address this question, we examined the development in several species of pelagiid jellyfish. Most members of Pelagiidae have a complex life cycle with a sessile polyp that gives rise to ephyrae (juvenile medusae); but one species within Pelagiidae, Pelagia noctiluca, spends its whole life in the water column, developing from a larva directly into an ephyra. In many complex life cycles, adult features develop from cell populations that remain quiescent in larvae, and this is known as life cycle compartmentalization and may facilitate the evolution of direct life cycles. A second type of metamorphic processes, known as remodeling, occurs when adult features are formed through modification of already differentiated larval structures. We examined muscle morphology to determine which of these alternatives may be present in Pelagiidae. SN - 2041-9139 UR - https://doi.org/10.1186/s13227-015-0005-7 DO - 10.1186/s13227-015-0005-7 ID - Helm2015 ER -