''Baseodiscus mexicanus'' is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

proboscis worm Nemertea is a phylum of animals also known as ribbon worms or proboscis worms, consisting of 1300 known species. Most ribbon worms are very slim, usually only a few millimeters wide, although a few have relatively short but wide bodies. Many h ...

in the family Valenciniidae.

Description

This species commonly grows 1 to 2 metres long and 5 to 7 mm wide. It does not contract significantly when physically contacted or killed. When it does actually contract strongly, it has a flattened appearance, being widest immediately behind the back of the head. The part of the body containing the intestines is flat and broad. The posterior is very thin.

Distribution

''Baseodiscus mexicanus'' is found in abundance on the Pacific east coast in the waters of Panama and Mexico, as well as in the Galapagos Islands. It has been found nowhere else.

References

Heteronemertea Marine animals Animals described in 1893 {{Nemertean-stub