Cratera tui

Cratera tui is a species of land planarian belonging to the subfamily Geoplaninae. It is found in Serra da Bocaina National Park and Itatiaia National Park in Brazil.

Description
Cratera tui is a flatworm around 45–70 mm in length and 7 mm in width. The body is slightly lanceolate, with parallel margins, a rounded front tip, and a pointed back tip. The body is widest at the pharynx, with a gradual narrowing towards the front and an abrupt narrowing towards the back tip. The dorsal side of the body has a melon yellow median stripe that is bordered on both sides by a jet black stripe. Outside of the jet black stripes are traffic white marginal stripes. The body margin is jet black. The front of the body fades into a carmine red color. The ventral side of the body is grey-white.

Aside from its coloration and length, it is distinguished from other members of Cratera by having marginal eyes, a cylindrical pharynx, a pharyngeal pouch that is 0.6 mm anterior to the prostatic vesicle, a penis papilla that is shorter than the male atrium, a relatively small distal dilation of the ejaculatory duct, a female atrium that is 2.5 times longer than the male, and the presence of a long common glandular ovovitelline duct.

Etymology
The specific epithet is derived from the Tupi language word tui, "tiny, insignificant", in reference to the small size of the ejaculatory duct's distal dilation.