Obsidianus

Obsidianus is a Latin adjective used in scientific naming to indicate resemblance to obsidian, the black, glassy volcanic rock. The word derives from obsidium or obsidian and is commonly used as a specific epithet in binomial nomenclature across zoology, botany, and microbiology. When employed, it typically signals a dark coloration or a glossy, glassy texture that reminded the describer of obsidian, though the exact reasoning varies by case and is recorded in the species description.

In taxonomic practice, obsidianus must agree in gender with the genus. The masculine form is obsidianus, the feminine form obsidiana, and the neuter form obsidianum. As a descriptive epithet, it does not indicate phylogenetic relationships, only a perceived similarity.

Notable usage spans multiple taxa, making it a relatively common descriptive epithet, though the same word may appear in unrelated groups. The epithet is most informative when consulted alongside the original species description or taxonomic notes, which clarify why the author chose the term and any locality associations with obsidian deposits.

In summary, obsidianus serves as a conventional Latin descriptor in scientific names to convey a resemblance to the dark, glassy mineral obsidian, rather than to denote a taxonomic rank or lineage.