Morphological and molecular characterization of an undescribed vestibuliferid ciliate from the captive-bred naked mole-rat, Heterocephalus glaber (Rodentia: Bathyergidae).

The intestinal ciliates of the naked mole-rat (Heterocephalus glaber) remain poorly characterized. Previous reports identified a Balantidium or suggested an association with Meiostoma; however, their taxonomic identities have not been verified using morphological and molecular approaches. In March 2024, numerous ciliates were detected in fecal samples from a captive colony of naked mole-rats at a zoo in Japan. The ciliate was characterized using light microscopy, scanning electron microscopy, and molecular analyses based on the nuclear ribosomal RNA gene sequences. The ciliate exhibited morphological characteristics typical of vestibuliferid ciliates. Molecular analyses based on ribosomal RNA regions revealed a distinct lineage related to Balantioides coli (syn. Balantidium coli) and other vestibuliferid ciliates. These morphological and molecular data indicate that the ciliate from the naked mole-rat represents a previously unrecognized vestibuliferid lineage. This study provides new insights into the diversity and taxonomy of intestinal ciliates associated with naked mole-rats.