What's the singular form of microcephalus? Here's the word you're looking for.
Answer
The noun microcephalus is uncountable.
The singular form of microcephalus is also microcephalus.
Examples
Distribution, reproduction and feeding of the Greenland shark Somniosus microcephalus, with notes on two other sleeper sharks, Somniosus pacificus and Somniosus antarcticus.