Programa de Pós-Graduação em Ciências Fisiológicas, Instituto de Ciências Biológicas, Universidade Federal do Rio Grande-FURG, Rio Grande, Brazil.
Laboratório de Pesquisas de Elasmobrânquios, Instituto de Biociências, Universidade Estadual Paulista "Júlio de Mesquita Filho", São Vicente, Brazil.
J Fish Biol. 2020 Jul;97(1):309-313. doi: 10.1111/jfb.14368. Epub 2020 May 20.
This study describes the fetal mummification process in two embryos of a 310 cm total length scalloped hammerhead shark Sphyrna lewini caught in southeastern Brazil, in December 2017. Fourteen embryos were observed in total, in which two males in the left uterus presented different stages of mummification. Both mummified embryos were covered by an exudate (i.e., a mucous substance), indicating a hematic mummification process. All embryos were at the placentotrophic stage of development, indicating that they were close to parturition. An intrinsic characteristic is suggested as possible etiology for this condition, such as umbilical torsion, because both embryos were at different sizes and, therefore, at different development stages. In addition, the sample size did not allow the authors to presume any pollution effect once only one female was observed. Finally, fetal mummification and other embryonic development disorders might have populational impacts due to reduction in embryo survival and, consequently, recruitment. For this reason and considering that S. lewini is categorized as a "critically endangered species," this study's results have conservational relevance.
本研究描述了 2017 年 12 月在巴西南部捕获的一条 310 厘米长的斜齿鲨 Sphyrna lewini 的两个胚胎的木乃伊化过程。总共观察到 14 个胚胎，其中左子宫中的两个雄性呈现出不同阶段的木乃伊化。两个木乃伊化的胚胎都被渗出物（即粘液物质）覆盖，表明存在血液木乃伊化过程。所有胚胎都处于胎盘营养阶段，表明它们即将分娩。这种情况的内在特征可能是脐带扭转等原因，因为两个胚胎大小不同，因此处于不同的发育阶段。此外，由于只观察到一只雌性，样本量不足以假设任何污染影响。最后，由于胚胎存活率降低，以及由此导致的补充减少，胎儿木乃伊化和其他胚胎发育障碍可能会对种群产生影响。出于这个原因，并且考虑到斜齿鲨被归类为“极度濒危物种”，本研究的结果具有保护意义。
