First Record of a Pregnant Female of Dasyatis hypostigma, with Description of the Embryos

Reproduction and embryonic development of the red stingray Hemitrygon akajei from Ariake Bay, Japan

“…Embryos were classified into 9 developmental cohorts based on easily recognized morphological characteristics (Table 1). Using data extracted from the literature and including this study, a simple linear regression was used to model the relationships between DW of females and maximum size of young at birth and maximum fecundity for Dasyatinae species: Bathytoshia brevicaudata (Hagiwara 1993;Last and Stevens 2009), Bathytoshia centroura (Struhsaker 1969;Reed and Gilmore 1981;Capapé 1993), Bathytoshia lata (Uchida et al 1990;Furumitsu et al 2012), Dasyatis chrysonota (Ebert and Cowley 2009); Dasyatis hypostigma (Ribeiro et al 2006), Dasyatis marmorata (Capapé and Zaouali 1995), Dasyatis pastinaca (Capapé 1976;Serena 2005;Saadaoui et al 2015), Hemitrygon akajei (Hagiwara 1993), Hypanus americanus (Ramírez-Mosqueda et al 2012;Tagliafico et al 2013), Hypanus dipterurus (Smith et al 2007), Hypanus guttatus Lessa 2006, 2007;Tagliafico et al 2013), Hypanus longus (Villavicencio-Garayzar et al 1994), Hypanus marianae (Yokota and Lessa 2007), Hypanus rudis (Springer and Collette 1971), Hypanus sabinus (Snelson et al 1988;Johnson and Snelson 1996), Hypanus say (Snelson et al 1989), Megatrygon microps (Nair and Soundararajan 1976;Pierce et al 2008), Pteroplatytrygon violacea (Wilson and Beckett 1970;Mazzoleni and Schwingel 2002;Mollet et al 2002;Hemida et al 2003;Forselledo et al 2008;Veras et al 2...…”

“…There has been no study of the reproductive biology of H. akajei throughout its range, but some reproductive traits are common among dasyatids. Dasyatid stingrays have a single functional left ovary and uterus and reproduce via aplacental viviparity with lipid histotrophy (Capapé 1976;Snelson et al 1988;Ribeiro et al 2006;Veras et al 2014). Mating is followed immediately by ovulation and fertilization with no evidence for female sperm storage.…”

Egg preservation in an Eocene stingray (Myliobatiformes, Dasyatidae) from Italy

“…In dasyatids, the ovaries of mature individuals contain oocytes throughout the year that are embedded in the connective tissue: the onset of ova maturation marks the growth and development of the oocytes. During ovulation, the largest mature ova are released from the ovary, moving to the ostium and oviduct (Maruska et al, 1996; Hamlett and Koob, 1999; Hamlett et al, 2005; Ribeiro et al, 2006; Burns et al, 2014).…”

“…Available data on the fecundity of extant myliobatiform species with viviparous (histotroph) mode of reproduction indicate an average of 4.4 eggs per year, although values range from 1–3 for Hypanus longus to 2–10 for H . americanus (Musick and Ellis, 2005; Ribeiro et al, 2006; variation data within a species and not a population). The relatively large size and low number of eggs in MGGC 7456 (four, possibly six) are consistent with the reproductive physiology observed among extant dasyatids.…”

PCR–RFLP analysis to identify four ray species of the genus Dasyatis (Elasmobranchii, Dasyatidae) fished along the southeastern and southern coast of Brazil

“…However, controversy exists regarding the taxonomic status and distribution of the respective Dasyatis species. For instance, D. hypostigma has been misidentified as D. say (Santos and Carvalho, 2004;Ribeiro et al, 2006;Mazzoleni and Schwingel, 1999). D. hypostigma occurs along the southern Brazilian coast down to Argentina, and D. say is restricted to the northwestern Atlantic Ocean, Gulf of Mexico, and Caribbean Sea (Charvet-Almeida and de Carvalho, 2006;Santos and Carvalho, 2004;Snelson et al, 2006).…”