Simplify the following text for a Grade 10 native English-speaking person.
Original: It has sometimes been considered synonymous with Pipistrellus tenuis ; however , revisions of the genus based on baculum have identified Pipistrellus murrayi as a distinct species .
Simplified: It was thought to be the same as the Pipistrellus tenuis , but new research on the bat 's baculum , ( a penis bone ) , has shown that Pipistrellus murrayi is a different species .