Calamopleurus was a 3 foot long freshwater fish which lived in Brazil and northern Africa during the early and middle Cretaceous Period approximately 130-95 million years ago.

Calamopleurus belonged to a family called Amiidae. Today, the only surviving amiid is the Bowfin (Amia calva), which is native to southeastern Canada and the eastern United States, and typically grows to 2 feet long, although some unusually large specimens reaching 3.5 feet have been caught. The oldest-known fossils belonging to Amiidae date to the late Triassic Period, 213 MYA. Bowfins are a missing link between very archaic fish like gars (bowfins are actually related to gars) and more advanced bony fish; their skeletons are comprised of a mixture of both bone and cartilage. They were originally a very widespread and diverse group, with species inhabiting both freshwater and saltwater environments. The modern-day Bowfin is, therefore, considered by many to be a “living fossil” (Gilbert and Williams 2002, page 89).

The family Amiidae is divided into four sub-families: Amiinae, Amiopsinae, Solnhofenamiinae, and Vidalamiinae; Calamopleurus is classified as a member of Vidalamiinae. This sub-family is further split into two sub-divisions called “tribes”, which are Calamopleurini (found in South America and Africa) and Vidalamiini (found in North America, Europe, and Asia); Calamopleurus is the namesake member of the tribe Calamopleurini (Grande and Bemis 1998, pages 1-2).

Calamopleurus was named by the Swiss ichthyologist Louis Agassiz in 1841. The name literally means “reed side” in ancient Greek in reference to the thin straw-like shape of its ribs (Grande and Bemis 1998, page 406). The genus Calamopleurus is currently three divided into three species:

1. C. africanus, from the Kem Kem Beds of southern Morocco (middle Cretaceous Period, Cenomanian Stage, 100-95 MYA; originally tentatively dated to Albian Stage) (Forey and Grande 1998, pages 179-195; Sereno et al 1996, pages 986-991).
2. C. cylindricus, from the Santana Formation of northeastern Brazil (middle Cretaceous Period, late Aptian to early Albian Stage, 115-105 MYA) (Grande and Bemis 1998, pages 406-442).
3. C. mawsoni, from the Ilhas Formation of eastern Brazil (early Cretaceous Period, date uncertain, circa 144-128 MYA) (Grande and Bemis 1998, pages 406, 443-447).

In the past, it was believed that there was a fourth species, C. anglicus, which was native to southern Britain. There is only one reference to this animal in a book entitled The Geology and Fossils of the Tertiary and Cretaceous Formations of Sussex, written by Frederick Dixon and published in 1850. The source reads as follows: “This beautiful fish, from the collection of Sir Philip Egerton, was found in Kent, and is the only example of the genus yet discovered in England…This species is larger than the Brazilian one [C. cylindricus], being when perfect about 16 inches in length; the caudal extremity is wanting in the fossil. The head was small, the body cylindrical, and the scales large and smooth; when seen under the microscope, they exhibit fine radiating lines…; the mouth was capable of great distention; the teeth are minute; the dorsal fin is placed about the middle of the back” (Dixon 1850, pages 375-376). In 1889, Arthur S. Woodward argued that this identification was incorrect and that this specimen ought to be ascribed to another genus called Syllaemus, which had also been named by Frederick Dixon (Woodward 1889, pages 351-353). This specimen was re-assigned once again in 1978 to another genus called Apsopelix, which had been named in 1871 (Teller-Marshall and Bardack 1978, pages 6-25).

A skeleton of Calamopleurus cylindricus from eastern Brazil (collection ID code: FMNH PF14348a). Length of 46.3 cm. Grande and Bemis 1998, page 410.

A well-preserved specimen of Calamopleurus cylindricus showing scale patterns (collection ID code: FMNH PF14348b). Length of 46.3 cm. Grande and Bemis 1998, page 411.

Skull and skeleton of Calamopleurus cylindricus (collection ID code: AMNH 11837). Grande and Bemis 1998, pages 425; 414.

As you can see from the photographs above, the mouth of this animal was angled upwards – this is referred to anatomically as having a “superior” mouth. This is a feature that you frequently see in fish which are either ambush hunters lying near the bottom or else cruise close to the water’s surface and eat things which are floating. Overall Calamopleurus possess the general shape of an ambush hunter, lurking amidst the thick underwater vegetation and then shooting forwards at great speed like a pike.

Given the large size of this animal’s teeth, it may be tempting for some paleo-artists to portray this animal with an intimidating Cheshire Cat grin bristling with sharp fangs. Please don’t do this. Remember that the modern-day Bowfin, which Calamopleurus is related to, also has large teeth in proportion with its skull size, but you don’t see them because they are obscured by thick lips. Calamopleurus was almost certainly the same. Outwardly, Calamopleurus would have looked more like a trout than a barracuda, and it probably lived the same sort of lifestyle too.

Despite the fact that it didn’t have an obvious toothy grimace, Calamopleurus evidently had a ravenous appetite. There are a few fossils of this animal which have been found that had smaller fish stuffed in its mouth. Evidently, its eyes were too big for its stomach, and it choked to death on its prey. Click here, here, and here to see images of this.

Below is a drawing which I made of the type species Calamopleurus cylindricus. The drawing was made with a black ballpoint pen and colored pencils on printer paper.

Calamopleurus cylindricus. © Jason R. Abdale (April 29, 2023).

Please visit my “Fine Art America” page here to purchase prints of my artwork.

Keep your pencils sharp.

Bibliography

Dixon, Frederick. The Geology and Fossils of the Tertiary and Cretaceous Formations of Sussex. London: Longman, Brown, Green and Longmans, 1850.
https://www.biodiversitylibrary.org/bibliography/14790.

Forey, Peter L.; Grande, Lance (1998). “An African twin to the Brazilian Calamopleurus (Actinopterygii: Amiidae)”. Zoological Journal of the Linnean Society, volume 123, issue 2 (June 1998). Pages 179-195.
https://academic.oup.com/zoolinnean/article/123/2/179/2684441.

Grande, Lance; Bemis, William E. (1998). “A comprehensive phylogenetic study of amiid fishes (Amiidae) based on comparative skeletal anatomy: An empirical search for interconnected patterns of natural history”. Journal of Vertebrate Paleontology, volume 18, supplement 1 (1998). Pages 1-696.

Sereno Paul C.; Dutheil, Didier B.; Iarochene M.; Larsson, Hans C. E.; Lyon, Gabrielle H.; Magwene, Paul M.; Sidor, Christian A.; Varricchio, David J.; Wilson, Jeffrey A. (1996). “Predatory dinosaurs from the Sahara and Late Cretaceous faunal differentiation”. Science, volume 272 (May 17, 1996). Pages 986-991.

Teller-Marshall, Susan; Bardack, David (1978). “The morphology and relationships of the Cretaceous Teleost Apsopelix“. Fieldiana: Geology, volume 41, issue 1 (1978). Pages 1-35.
https://www.biodiversitylibrary.org/item/21643#page/9/mode/1up.

Woodward, Arthur Smith. Catalogue of the Fossil Fishes in the British Museum (Natural History), Part IV. London: Longmans & Co., 1889.
https://archive.org/details/cataloguefossil00brita/page/n3/mode/2up.

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Tags: Africa, art, bowfin, Calamopleurus, Cretaceous Period, Early Cretaceous, fish, Melvius, Mesozoic, Middle Cretaceous, paleo-art, paleontology, Prehistoric, South America