Alaska Fisheries Science Center, National Oceanic and Atmospheric Administration, National Marine Fisheries Service, Seattle, WA 98115, USA.
J Fish Biol. 2009 Feb;74(3):483-501. doi: 10.1111/j.1095-8649.2008.02138.x.
Embryo development events were correlated with egg-case changes for the Aleutian skate Bathyraja aleutica and the Alaska skate Bathyraja parmifera. Yolk absorption underwent two phases: that of steady absorption during early development and that of rapid yolk absorption during the final development stages. Total length (L(T)) for 50% of the pre-hatching embryos egg-case jelly disappearance was 92.04 mm (range 81-102 mm) and 99.36 mm (range 81-100 mm) for B. aleutica and B. parmifera, respectively, allowing the inner chamber to open to seawater flow. The tail filament underwent three phases of growth: rapid elongation during early development (<100 mm embryo L(T)), stasis of tail filament length during the remainder of embryo development and rapid absorption soon after hatching. Complete tail filament development coincided with the disappearance of egg-case jelly. Clasper buds first developed at embryos >70 mm L(T) for both species and the sex ratio was 1:1 well before hatching. Egg cases that were devoid of an ova or developing embryo were c. 5.0 and 6.5% of the egg cases examined for B. aleutica and B. parmifera, respectively. Measurements showed that egg cases containing only egg jelly were smaller in both width and length than those possessing an ova. Embryo stages were punctuated with distinct events that correlated with egg case changes controlling the internal environment of the developing embryo.
胚胎发育事件与卵鞘变化相关联，研究对象为阿留申长尾鲨（Bathyraja aleutica）和阿拉斯加长尾鲨（Bathyraja parmifera）。卵黄吸收经历两个阶段：早期发育时的稳定吸收阶段和后期快速吸收阶段。孵化前胚胎卵壳果冻消失时的总长度（L(T)）的 50%分别为 92.04 毫米（范围 81-102 毫米）和 99.36 毫米（范围 81-100 毫米），这使得内室能够开放到海水流动中。尾丝经历了三个生长阶段：早期发育时的快速伸长（<100 毫米胚胎 L(T)）、胚胎发育其余部分的尾丝长度停滞和孵化后迅速吸收。完全的尾丝发育与卵壳果冻的消失同时发生。夹钳芽首先在两个物种的胚胎长度大于 70 毫米时发育，性别比例在孵化前就达到了 1:1。卵壳中没有卵子或正在发育的胚胎的比例分别为阿留申长尾鲨和阿拉斯加长尾鲨卵壳的 5.0%和 6.5%。测量结果表明，仅含有卵黄的卵壳在宽度和长度上都比含有卵子的卵壳小。胚胎阶段以与卵壳变化相关的明显事件为标志，这些事件控制着胚胎的内部环境。
