Completely Direct Development of Abatus cordatus, a Brooding Schizasterid (Echinodermata: Echinoidea) from Kerguelen, With Description of Perigastrulation, a Hypothetical New Mode of Gastrulation.
Completely Direct Development of Abatus cordatus, a Brooding Schizasterid (Echinodermata: Echinoidea) from Kerguelen, With Description of Perigastrulation, a Hypothetical New Mode of Gastrulation.
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完全直接开发 Abatus cordatus，一种来自凯尔盖朗的育雏 Schizasterid（棘皮动物：Echinoidea），并描述了原肠胚周围形成，一种假设的新原肠胚形成模式。
DOI：
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发表时间：
1996
期刊：
影响因子：
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通讯作者：
J. Féral
中科院分区：
文献类型：
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作者：
P. Schatt;J. Féral
描述了育雏 schizasterid Abatus cordatus 的发育，这是凯尔盖朗特有的亚南极海胆类动物。雌性产下直径为 1300 微米的非浮力卵，由细长的精子（头部宽 1 微米，长 15 微米）受精。这一发育的主要特征是（1）从动物极开始不完全卵裂，成为全胚细胞，受精后26天产生充满皱纹的囊胚； (2) 原肠胚内陷期间，卵黄周间隙中的间充质细胞在原肠胚内陷期间从动物到植物极的明显外部迁移（尚未进行命运图谱研究）； (3) 在原肠胚形成结束时（受精后 65 天）孵化； (4) 原肠胚形成结束后，前庭就与增厚的口腔表皮区分开来； (5)直接从原肠胚产生幼体，无需任何幼虫阶段。离开育雏室的幼鱼直径为2毫米，年龄约为250天。 A. cordatus 是真正的完全直接发育（没有幼虫，也没有变态）。我们建议使用（1）术语“原肠胚形成过程”，作为在获得更明确的研究之前的暂定术语，来描述原肠胚形成过程中细胞假设的特殊运动；（2）“直接发育”一词仅适用于完全直接发育的物种，而“简短发育”则适用于或多或少经过转化的物种。
Development of the brooding schizasterid Abatus cordatus, a subantarctic echinoid endemic to Kerguelen, is described. Females spawn nonbuoyant eggs 1300 μm in diameter, which are fertilized by elongated sperm (head 1 μm wide and 15 μm long). The main characteristics of this development are (1) incomplete cleavage beginning at the animal pole that becomes holoblastic, giving a filled wrinkled blastula 26 days after fertilization; (2) apparent (fate-mapping studies have not been done) external migration of mesenchyme cells, in the perivitelline space, from the animal to the vegetal pole during gastrulation while the archenteron invaginates; (3) hatching occurring at the end of the gastrulation (65 days after fertilization); (4) differentiation of the vestibule from a thickening of the oral epidermis as soon as the end of gastrulation is attained; and (5) production of a juvenile directly from the gastrula without any larval stage. The juvenile that leaves the brood chamber is 2 mm in diameter and about 250 days old. A. cordatus is a true completely direct developer (no larva and no metamorphosis). We propose to use (1) the term perigastrulation, as a tentative one until more definitive studies are available, to describe the hypothetical peculiar movement of cells during gastrulation and (2) the terms of direct development only for completely direct developing species and abbreviated development for species that have more or less transformed plutei.