New Foot-Long Tapeworms Discovered

February 13, 2009

LiveScience

(Feb. 12) - A major group of tapeworms, parasitic flatworms that can grow to

more than 30 feet long in the digestive tracks of humans, fish and other

animals while absorbing their nutrients, has been discovered by Canadian

researchers.

The new tapeworm group, an order now dubbed Rhinebothriidea and that

includes worms that parasitize stingrays and grow up to a foot long, was

established

as new to science by Claire J. Healy, a curator at the Royal Ontario Museum

in Toronto, and her colleagues.

The parasite group, announced by Canadian

researchers in February, includes worms that inhabit stingrays and can grow up

to

a foot long. Click to see more recently discovered creatures.

Infection with a tapeworm is rare in the United States. People are often

unaware they are infected, via an animal or water, but symptoms can include

abdominal pain, nausea, vomiting, loss of appetite and malnutrition. The

treatment is a pill that kills the worm and helps the body expel it.

The discovery of the order Rhinebothriidea, which includes five genera new

to science, represents a significant step forward in terms of understanding

the evolutionary interrelationships of tapeworms, Healy said. The order is

detailed in the March 2009 issue of the International Journal for Parasitology.

" This study illuminates an important part of the backbone of the tapeworm

tree of life, " Healy said. " It sets the stage for further research into the

evolutionary relationships among tapeworms. "

Catch-All Category Re-Examined

The research started with a comprehensive study of a group of tapeworms that

parasitize batoid fishes (stingrays and their relatives). Scientists

previously had classified these worms classified within a subfamily of the

Tetraphyllidea, an order that has lost credibility over the last two decades

and is

now viewed as a catch-all category for species that did not clearly fall within

other orders, Healy said.

Recommended Posts