Ultrasound sheds light on manta ray development

Science : Researchers in Okinawa, Japan, used ultrasound to study a pregnant manta ray’s embryo. Because manta rays give birth to live young but have no umbilical cord, the researchers wanted to determine how the embryos get oxygen. From examining video taken of the ultrasound, Taketeru Tomita at Hokkaido University Museum found that the baby ray “was raising and lowering its jaw, pumping uterine fluid in through its mouth and spiracle, an opening on the back of the head,” writes Helen Fields for Science. Such studies will help scientists understand how rays evolved to produce live young. This work by Tomita and colleagues appears online today in Biology Letters.