Mid 19th century (in an earlier sense). From scientific Latin mystacinus from ancient Greek μυστακ-, μύσταξ moustache + scientific Latin -inus, -ina. Compare French mystacin, noun.
Definition of mystacine in US English:
mystacine
adjectiveˈmɪstəsʌɪn
Zoology rare
Designating the whiskered bat Myotis mystacinus.
Origin
Mid 19th century (in an earlier sense). From scientific Latin mystacinus from ancient Greek μυστακ-, μύσταξ moustache + scientific Latin -inus, -ina. Compare French mystacin, noun.