glabellus

Glabellus is a Latin adjective meaning hairless or smooth, used in scientific naming to describe a surface or feature that lacks hairs or pubescence.

In taxonomy, glabellus functions as a descriptive epithet within species names and is formed to agree in gender with the genus name. Masculine forms appear with masculine genera, while feminine or neuter forms accompany feminine or neuter genera. The epithet is commonly translated into English as glabrous or hairless.

The term appears across various groups in biological nomenclature, including plants, animals, fungi, and other organisms. It typically signals a diagnostic trait where the organism exhibits a notably hairless or smooth surface compared with related taxa, such as a hairless leaf surface or a smooth exoskeleton. Its use is more common in traditional or older taxonomic descriptions, though it remains valid in modern species naming when the trait is observed.

Glabellus should not be confused with glabella, which refers to a different anatomical region in some organisms. It also serves as a reminder that Latin descriptors in binomials convey specific morphological observations, and their precise form adjusts to the grammatical gender of the genus they accompany.