Monosmilus

Monosmilus
Temporal range: Middle Eocene (Lutetian)
Scientific classification
Kingdom:
Animalia
Phylum:
Chordata
Class:
Actinopterygii
Order:
Clupeiformes
Superfamily:
Engrauloidea
Family:
†Clupeopsidae
Genus:
†Monosmilus

Capobianco et al., 2020
Species:
†M. chureloides
Binomial name
†Monosmilus chureloides
Capobianco et al., 2020

Monosmilus is an extinct genus of anchovies. It contains a single species, M. chureloides, from the Middle Eocene (Lutetian) of Punjab, Pakistan.

The generic name Monosmilus is the Ancient Greek word of "single knife", while the specific epithet chureloides refers to the Churel, a shapeshifting vampire-like demon from South Asian folklore.

Monosmilus is often colloquially called the saber-tooth anchovy.

Discovery

Monosmilus is exclusively known from the holotype GSP-UM 37, preserved at the Geological Survey of Pakistan, Quetta. Using micro-CT scans, a team of researchers scanned its skull, revealing an unusual dental structure featuring a sharp fang from the upper jaw and a row of at least eight sharp teeth.

Description

Appearance

Monosmilus was a carnivorous stem-engraulid. The dorsal part of the neurocranium (braincase) is incomplete. The vomer had two deep pits and unlike most anchovies, this fish strangely had a massive fang, hence its name. This species could reach around 1 metre (3.3 ft) long. Within the upper jaw, only the maxilla is preserved, but it is otherwise incomplete.

The lower jaw was lined with a row of sharp teeth (at least eight teeth), separated by deep pits. The lateral ethmoids were big and bulbous. Rakers, if present, were probably small.

Relatives

The closest relative of Monosmilus is Clupeopsis, which is from Belgium. They form a peculiar clade known for their fangs, something that is rare in many fish. No fish, whether extinct or living, share these features known in these genera.

Paleoecology

Unlike many modern anchovies today, which are planktivores, Monosmilus likely preyed on other fish. But there is no living analogue, so the function of the tooth remains uncertain.

References

  1. 1 2 3 4 5 6 7 8 9 10 11 Capobianco, Alessio; Beckett, Hermione T.; Steurbaut, Etienne; Gingerich, Philip D.; Carnevale, Giorgio; Friedman, Matt (2020). "Large-bodied sabre-toothed anchovies reveal unanticipated ecological diversity in early Palaeogene teleosts". Royal Society Open Science. 7 (5) 192260. Bibcode:2020RSOS....792260C. doi:10.1098/rsos.192260. ISSN 2054-5703. PMC 7277248. PMID 32537214.
  2. ↑ "PBDB Taxon".
  3. 1 2 3 "Meter-long saber-toothed anchovies roamed the seas around 50 million years ago | U-M LSA Museum of Paleontology". lsa.umich.edu. Retrieved 2026-08-28.
  4. 1 2 "Saber-toothed anchovies roamed the oceans 45 million years ago". www.science.org. Retrieved 2026-08-28.
  5. ↑ Yirka, Bob; Phys.org. "Prehistoric anchovy-like fish had large fangs and a saber tooth", phys.org, retrieved 2024-08-17

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