Larval Development (with Observations on Spawning) of the Pencil Urchin Phyllacanthus imperialis: a New Intermediate Larval Form?
Larval Development (with Observations on Spawning) of the Pencil Urchin Phyllacanthus imperialis: a New Intermediate Larval Form?
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铅笔海胆 Phylacanthus Imperialis 的幼虫发育（及产卵观察）：一种新的中间幼虫形态？
DOI：
10.2307/1542131
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发表时间：
1993
期刊：
影响因子：
--
通讯作者：
C. Young
中科院分区：
文献类型：
--
作者：
R. R. Olson;J. Cameron;C. Young
信息了解棘皮动物幼虫从喂养到nonfeeding的进化转变，可以从物种的幼虫发育模式似乎是这些极端之间的中间。在本文中，我们报告了这样一个物种的发展。在澳大利亚的吕宋岛，连续两年，铅笔海胆Phyllacanthus imperialis的产卵与石珊瑚的大量产卵同步。卵大，卵黄质，直径507 μm，发育成不摄食的棘亲鱼幼虫，有两对幼虫臂。臂被确定为口后和背后，这是第一和第三对典型的棘足类。幼虫的骨骼，骨骼杆延伸的手臂的长度。2日龄时，幼鱼的原基出现5个初级足。受精后4天开始变态和定居。2日龄幼虫的组织学检查发现存在一个发展中的肠道，但没有开口，在什么将是一个典型的棘足类的口腔区域，或在老年幼虫的少年雏形的口腔表面。像其他的雪螨幼虫一样，这个物种没有羊膜内陷的证据。帝国棘球蚴的形态介于摄食和非摄食棘球蚴之间。在口部区域的纤毛带的痕迹和棘尾虫幼虫典型的手臂的存在表明了它的进化历史，而卵的大尺寸和没有嘴暗示了它的未来。这种幼虫形式提供了深入了解的发展变化，发生在转变过程中，从lectotrophy到lectotrophy在海胆幼虫。
Information for understanding the evolutionary shift from feeding to nonfeeding in echinoderm larvae can be gained from species whose larval development pattern appears to be intermediate between these extremes. In this paper we report the development of one such species. The pencil urchin Phyllacanthus imperialis spawned synchronously with the mass spawning of scleractinian corals at Lizard Island, Australia, in two consecutive years. Their large yolky eggs (507 μm diameter) developed into nonfeeding echinopluteus larvae with two pairs of larval arms. The arms were identified as postoral and posterodorsal, which are the first and third pairs in typical echinoplutei. A larval skeleton was present, with skeletal rods extending the length of the arms. Five primary podia of the juvenile rudiment appeared at 2 days of age. Metamorphosis of the larvae and settlement began 4 days after fertilization. Histological examination of 2-day-old larvae revealed the presence of a developing gut, but no mouth opened in what would be the oral region of a typical echinopluteus, or the oral surface of the juvenile rudiment in older larvae. Like other cidaroid larvae, this species showed no evidence of an amniotic invagination. The larva of P. imperialis appears to be a transitional form between the morphology of feeding and nonfeeding echinoid larvae. Traces of the ciliary band in the oral region and the presence of arms typical of the echinopluteus larva indicate its evolutionary past, whereas the large egg size and absence of a mouth hint at its future. This larval form provides insights into developmental changes that occur during the shift from planktotrophy to lecithotrophy in echinoid larvae.
海胆直接发育进化的约束、灵活性和系统发育史。
影响因子：
2.7
作者：
Raff,RA
通讯作者：
Raff,RA