LB10445
LB10445 was the Federation designation for a microscopic ciliated lifeform known to exist only on the planet Devidia II in the Marrab sector. 

In 2368, a LB10445 fossil was found in a cavern on Earth in which Data's severed head was also found, evidence that indicated the presence of extraterrestrials there during the 19th century. ()

de:LB10445
Microorganisms