It contains a single species, M. chureloides from the Middle Eocene (Lutetian)-aged Domanda Formation of Punjab, Pakistan.

[1][2][3] Monosmilus was a large, predatory stem group-anchovy that may have reached up to 1 metre (3.3 ft) in length.

Its most distinctive feature was a single, massive fang projecting downwards from vomerine region of the upper jaw.

The genus name "Monosmilus" means "single knife" in Ancient Greek, referencing this fang, while the specific epithet "chureloides" references the Churel, a fanged, shapeshifting demon of Pakistani folklore.

The saber-toothed anchovies were part of a wider radiation of predatory marine fish during the early Paleogene, in the aftermath of empty ecological niches remaining from the Cretaceous-Paleogene extinction event.