Fetal mummification in silky shark (Carcharhinus falciformis) from the Gulf of California, Mexico

Abstract

ABSTRACT

Re‐evaluation of reproductive cycle and fecundity of finetooth sharks Carcharhinus isodon (Valenciennes 1839) from the Northwest Atlantic Ocean, with new observations on ovarian cycle and reproductive endocrinology of biennially reproducing sharks

“…One aspect of C. isodon reproduction that was observed in this study but not previously reported was an unexpectedly high rate of EED, which was observed in 11% of pregnant females examined. Although embryo death consistent with that observed in this study ( i.e ., the presence of infertile eggs and/or malformed, growth‐retarded or “mummified” embryos) has been previously reported in other shark species (Clark & von Schmidt, 1965; Martins et al ., 2020; Parsons, 1993; Randall, 1977; Rosa‐Molinar & Williams, 1983; Sandoval‐Castillo & Villavicencio‐Garayzar, 2008; Smale & Goosen, 1999; Springer, 1960), the factors that lead to such phenomena remain largely unknown. Nonetheless, irrespective of its causes, embryo loss can have negative effects on population growth in sharks.…”

“…It is also noteworthy that EED was more common in large females. This is a phenomenon that has not been reported in earlier studies focusing on EED in other shark species ( e.g ., Martins et al ., 2020; Rosa‐Molinar & Williams, 1983; Sandoval‐Castillo & Villavicencio‐Garayzar, 2008); nonetheless, it has been observed in some domestic species such as pigs (Borges et al ., 2005) and horses (Noakes et al ., 2009) although its causes remain unclear (Lefebvre, 2015). Nonetheless, this was believed to be responsible for the lack of a significant positive relationship between maternal size and brood size.…”

“…e., the presence of infertile eggs and/or malformed, growth-retarded or "mummified" embryos) has been previously reported in other shark species (Clark & von Schmidt, 1965;Martins et al, 2020;Parsons, 1993;Randall, 1977;Rosa-Molinar & Williams, 1983;Sandoval-Castillo & Villavicencio-Garayzar, 2008;Smale & Goosen, 1999;Springer, 1960), the factors that lead to such phenomena remain largely unknown. Nonetheless, irrespective of its causes, embryo loss can have negative effects on population growth in sharks.…”

First case of synophthalmia and albinism in the Pacific angel shark Squatina californica

“…The abnormalities observed in elasmobranchs in Mexico include bicephalia (Castro‐Aguirre & Torres‐Villegas, ; Galván‐Magaña et al , ), anophthalmia (Rubio‐Rodríguez et al , ), mummification (Sandoval‐Castillo & Villavicencio‐Garayzar, ), cephalic malformation (Escobar‐Sánchez et al , ; Blanco‐Parra & Niño‐Torres, ), cyclopia (Bejarano‐Álvarez & Galván‐Magaña, ) and albinism (de Jesus‐Roldán, ; Sandoval‐Castillo et al , ), the last being relatively more common among Chondrichthyes (Béarez, ). Albinism is defined as the lack of pigmentation (partial or total) of the body, derived from a genetic anomaly that results in the reduction of melanin biosynthesis.…”

Fetal Hematic Mummification in a Bitch: Case Report

“…Fetal mummification occurs though a series of morphological changes that occur with the fetus that is dead and is characterized by dehydration of embryos without decomposition or maceration by being kept hermetically closed within the uterus, preventing contamination [7,8].…”