División de Estudios de Posgrado, Universidad del Mar (UMAR), Campus Puerto Ángel, Distrito de San Pedro Pochutla, Puerto Ángel, Oaxaca, C.P. 70902, Mexico; Laboratorio de Ecología del Desarrollo, Universidad del Mar (UMAR), Campus Puerto Ángel, Distrito de San Pedro Pochutla, Puerto Ángel, Oaxaca, C.P. 70902, Mexico.
Laboratorio de Ecología del Desarrollo, Universidad del Mar (UMAR), Campus Puerto Ángel, Distrito de San Pedro Pochutla, Puerto Ángel, Oaxaca, C.P. 70902, Mexico.
Dev Biol. 2023 Jul;499:1-9. doi: 10.1016/j.ydbio.2023.04.005. Epub 2023 Apr 19.
Sea urchins play a key role in the marine environment, contributing to maintain a balance in benthic ecosystems. Toxopneustes roseus acts as a regulator of rhodolith beds and is a key species as a bioturbation promoter, while Rhyncholampas pacificus moderates the detritus content of sediment through various mechanisms and contributes to accelerating the circulation of organic matter. However, nothing is known about their early development, so the objective of this research is to characterize the embryonic and larval development of specimens of the two species from the southern Mexican Pacific and identify the causes that produce their differences. The embryonic development of T. roseus lasted approximately 20 h; the echinopluteus larva appeared at 23 h and culminated in around 12 days with an eight-armed larva. Metamorphosis was reached at 18 days. The embryonic development of R. pacificus lasted about 15 h; the larva emerged at 20 h and culminated in about two days with an eight-armed larva. The metamorphosis was completed in 9 days. The reproductive output of both species determines their development time and the structure of their larvae; therefore, the energy of R. pacificus is invested in reaching metamorphosis earlier to ensure that its larvae, which are not very abundant, settle and recruit to the population. Regarding T. roseus, the longest permanence in the plankton is efficiently maintained by its numerous larvae through the presence of mobile arms and the shift of the swimming function to the epauletes. This is the first work that characterizes the early development of a species of the genus Toxopneustes and of the only living species of the genus Ryncholampas. The information generated in this work is essential to gaining knowledge about these groups of echinoids, especially the effect of the environment on their early development.
海胆在海洋环境中起着关键作用，有助于维持底栖生态系统的平衡。紫海胆是藻床的调节者，也是促进生物搅动的关键物种，而太平洋石笔海胆通过各种机制调节沉积物中的碎屑含量，并有助于加速有机物的循环。然而，目前尚不清楚它们的早期发育情况，因此本研究的目的是描述来自墨西哥南部太平洋的这两个物种的胚胎和幼虫发育，并确定导致它们差异的原因。紫海胆的胚胎发育大约持续 20 小时；23 小时出现的海胆幼体，大约 12 天左右发育成 8 腕幼虫。18 天达到变态期。太平洋石笔海胆的胚胎发育大约持续 15 小时；20 小时出现的幼虫，大约两天左右发育成 8 腕幼虫。9 天完成变态期。这两个物种的生殖输出决定了它们的发育时间和幼虫的结构；因此，太平洋石笔海胆的能量投资于更早地达到变态期，以确保其数量不多的幼虫能够定居并招募到种群中。至于紫海胆，其大量的幼虫通过游动功能向肩章的转移和移动臂的存在，有效地维持了在浮游生物中最长时间的停留。这是首次对紫海胆属的一个物种和唯一现存的石笔海胆属的物种的早期发育进行描述。这项工作产生的信息对于了解这些海胆类群至关重要，特别是环境对它们早期发育的影响。
