Eptatretus wayuu Mok, Saavedra-Diaz & Acero P. 2001

Ventral aorta bifurcated into left and right branches at gill pouches one (anteriormost pouch) or two versus bifurcated at the fifth or sixth gill pouches in congeners and P. springeri. Five branchial apertures arranged in a straight line; lengths of efferent branchial ducts unequal with the first duct about twice the length of the last duct. Last branchial duct confluent with pharyngocutaneous duct, last aperture on the left side much larger than other apertures. Gill apertures 5. Slime pores: prebranchial 24; branchial 2; trunk 38-40; tail 9; total 73-75. Cylindrical body, laterally compressed toward spatulate tail. Caudal and ventral finfold well developed. Head, body, tail and finfold pink when fresh, dark violet in alcohol; eyespots faint, branchial region much lighter colored than other parts of the body; gill aperture margins pale (Ref. 41105).

Copulatory organ absent. The gonads of hagfishes are situated in the peritoneal cavity. The ovary is found in the anterior portion of the gonad, and the testis is found in the posterior part. The animal becomes female if the cranial part of the gonad develops or male if the caudal part undergoes differentiation. If none develops, then the animal becomes sterile. If both anterior and posterior parts develop, then the animal becomes a functional hermaphrodite. However, hermaphroditism being characterised as functional needs to be validated by more reproduction studies (Ref. 51361 ).