“I
was at the aquarium and I noticed that the stingrays all had patterns of black
specks on their backs. Was something wrong with them?”
After
doing some research, we found that there was probably nothing wrong with the
stingrays. Most likely, our patron was seeing the rays’ ampullae of Lorenzini,
special sensory organs shared by sharks, skates, and rays. The ampullae are
pores leading to jelly-filled canals that end in nerve endings, and they can act
as electroreceptors, sensing the electrical pulses given off by the muscle
activity of other creatures.They can also detect changes in temperature and
water pressure. If our patron had looked closely at the underside of the ray,
they would have seen many more ampullae, most clustered around its mouth. These
help the rays find food on the sea floor.
The
ampullae were first discovered by Marcello Malpighi in 1663, but were not
described in detail until 1678. Stefano Lorenzini was the first to describe
them, which is why they’re named after him. Though scientists were aware of the
ampullae, they did not understand their purpose until the 1960s.
We
found our information in Michele Debczak’s article “10 Stunning Facts about
Stingrays” on Mental Floss, Barbara
E. Wueringer and Ian R. Tibbetts’ research paper comparing the ampullary
systems of shovelnose rays in Reviews in Fish Biology and Fisheries, The Encyclopedia of Sharks by Steve and
Jane Parker, and Sharks: Ancient Predators in a Modern Sea by Salvador Jorgensen.
