Cheirolepis canadensis

Overview

Cheirolepis canadensis is a Late Devonian ray-finned fish. Its elongated, scaled trunk and asymmetrical tail extending farther upward catch the eye. It provides comparative evidence for early forms of the ray-finned fishes, a group containing many diverse fishes today.^[1]

Key facts

A 2013 review also summarizes reported cannibalism in Cheirolepis. Fossil food preserved in the digestive tract provided clues to relationships among small predators. Such records, as well as body shape, inform reconstructions of ancient food webs.^[1]

Time and place

Fossils are known from the Escuminac Formation at Miguasha on the Gaspé Peninsula in present-day Quebec, Canada. A 2013 review describes these strata as middle Frasnian in the Late Devonian. Ancient layers exposed along today’s coast lead into an old world of fishes.^[1]

The time range describes source context, not the complete duration of this species.

Size, form and skeleton

Articulated specimen MHNM05-71 preserves the sequence from head through scaled trunk to asymmetrical tail. The body tapers toward the rear, and the upper part of the tail extends farther. Follow the broad arrangement of the fins at the rear of the trunk and the tail.^[1]

The body length of Cheirolepis canadensis is summarized as about 53cm. This is the length from snout to tail tip gathered from the literature by a 2015 comparative study.^[13]

Habitat and reproduction

The review interpreted the environment of the Miguasha fishes as an estuary mixing freshwater and seawater. Cheirolepis there is introduced as a small predator. Feeding records of fishes of different sizes were examined together to explore its position in the food web.^[1]

Fossil discovery

The 2013 review synthesized the long-studied Miguasha fossil assemblage. Articulated Cheirolepis specimen MHNM05-71 was also introduced alongside fossils of other fishes. Comparing several animals from the same locality reveals this fish’s body features.^[1]

References

1. Cloutier (2013) — The world of Devonian fishes at Miguasha
2. Cloutier (2013) — The world of Devonian fishes at Miguasha
3. Cloutier et al. (2020) — Elpistostege and the origin of the vertebrate hand
4. Sépaq Miguasha (2013) — The discovery story of Elpistostege
5. Cloutier et al. 2020 · UQAR-hosted Nature paper, indexed body excerpt
6. International Commission on Stratigraphy (2024) — Geological time chart
7. Charest et al. (2023) — Median fins of fishes and evolution
8. Great Canadian Lagerstätten4. The Devonian Miguasha Biota (Québec)
9. Cloutier (2013) — The world of Devonian fishes at Miguasha
10. Béchard et al. (2014) — Bothriolepis examined using 3-dimensional digital imaging
11. International Commission on Stratigraphy (2024) — Geological time chart
12. Great Canadian Lagerstätten4. The Devonian Miguasha Biota (Québec)
13. Sallan·Galimberti (2015) — Changes in vertebrate size before and after the end-Devonian extinction

Research questions

The nature of the water at Miguasha was not judged from fish fossils alone. Researchers compared microfossils, sediments, and the chemical characteristics of rocks and bones together. The shift from an earlier lake interpretation to an estuarine understanding is a good example of combining different evidence.^[1]

Observation

The illustration is a qualitative external form based on an articulated specimen and the author’s species-specific comparative outline. The straightened body arrangement is reconstructed from the schematic; details of the head and fins, colors, and three-dimensional appearance are interpretive elements. Focus on the broad outline of an elongated body and asymmetrical tail.^[1]