Microplana nana Mateos et al., 1998

Jones, Hugh D. & Mcdonald, Jillian C., 2021, A new species of terrestrial planarian of the genus Microplana (Platyhelminthes Turbellaria; Tricladida: Continenticola) from Yorkshire, United Kingdom; with a discussion of Microplana humicola Vejdovsky 1890, Zootaxa 4980 (1), pp. 174-184 : 182

Microplana nana Mateos et al., 1998 , as amended by Vila-Farré et al., 2011.

Fully stretched living specimens were 8–10 mm long, 0.5 mm wide. Preserved specimens up to 4 mm long x 0.7 mm. The dorsal surface is greyish with darker spots all over the surface; anterior end darker; creeping sole white. The eyes are described as “small ocelli at the anterior end”. Photographs by E. Mateos (pers. comm) of live specimens show that in M. nana the pair of eyes are clearly visible and are each surrounded by a small white patch lacking the dark pigment. Our specimens are slightly smaller and the dark colouration is limited to the anterior rather than the whole length as in M. nana . We were not able to take macro pictures of the eyes of our specimens but the eyes are very small and not superficial, though the anterior end was strongly contracted. Microplana nana has approximately ten pairs of testes. The sperm ducts each expand anterior to the penis and contain stored sperm (false seminal vesicles), enter the base of the penis and discharge separately but close together to form the ejaculatory duct, similar to our specimens. The penis of M. nana is conical but the ejaculatory duct is eccentric, in the ventral half of the penis. The darker pigmentation, larger superficial eyes, and different position of the ejaculatory duct within the penis of M. nana compared to our specimens suggest that they are not of the same species.