The present study provides the first detailed early embryonic development of the Shalyni barb, Pethia shalynius (Yazdani & Talukdar, 1975), a vulnerable cyprinid fish occurring in streams and lentic waters of Meghalaya, northeast India. Induced spawning by synthetic hormone injection in May 2019 was conducted to a pair of mature female and male P. shalynius under controlled conditions in a well‐aerated aquarium. Fertilized eggs were spherical, 0.75–0.80 mm (approx.) in diameter, transparent, unpigmented and non‐adhesive. A total of 22 developmental stages could be categorized under seven broad periods, viz. the zygote, cleavage, blastula, gastrula, segmentation, pharyngula and hatchling. The first cleavage occurred at 15 min post fertilization (mpf), followed by blastulation at 01:23 hr post‐fertilization (hpf), gastrulation at 04:20 hpf, initial somite formation at 07:00 hpf, and pharyngula period at 19:20 hpf, respectively. Embryos hatched between 26–27 hpf and the newly‐hatched larvae ranged 2.2–2.5 mm in total length. For naturally‐declining populations of this vulnerable fish species, inferences drawn from the present study will help provide a baseline data for its conservation and management, and aid the research fields of developmental biology, biotechnology, molecular biology as well as taxonomy of this species.

中文翻译：

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脆弱的Shalyni倒钩Pethia shalynius的早期胚胎发育（Yazdani和Talukdar，1975年）

本研究提供了Shalyni倒钩Pethia shalynius（Yazdani＆Talukdar，1975）的第一个详细的早期胚胎发育过程，这是一种脆弱的塞浦路斯鱼类，产于印度东北部梅加拉亚邦的河水和片状水域。2019年5月通过合成激素注射诱导产卵，对一对成年雌雄P.shalynius在受控条件下，在通风良好的水族馆中。受精卵为球形，直径为0.75–0.80 mm（约），透明，无色素且无粘性。在七个大时期内，总共可以分为22个发展阶段。合子，卵裂，囊胚，胃，分割，咽和孵化。第一次卵裂发生在受精后15分钟（mpf），随后在受精后01:23 hr（hpf）进行爆破，在04:20 hpf进行胃形成，在07:00 hpf形成最初的松果体，并在19：咽期分别为20 hpf。胚胎在26–27 hpf之间孵化，而新孵化的幼虫的总长度为2.2–2.5 mm。对于这种脆弱鱼类的自然下降的种群，从本研究中得出的推论将有助于为其保护和管理提供基准数据，