Open Paleo

Cardiodon

Owen, 1841 Nomen dubium

From Greek 'kardia' ('heart') and 'odon' ('tooth'), for the almost heart-shaped crown of the tooth on which the genus was founded.

168.2–165.3 million years ago Bathonian, Middle Jurassic
Middle Jurassic stages

Cardiodon was a herbivorous genus of sauropod dinosaur, based on a tooth from the Middle Jurassic (late Bathonian) Forest Marble Formation of Wiltshire, England. Historically, it is very obscure and usually referred to Cetiosaurus, but recent analyses suggest that it is a distinct genus, and possibly related to Turiasaurus. Cardiodon was the first sauropod genus named.

Under dispute

The affinities of the type tooth are unresolved. Upchurch and Martin (2003) identified it as Eusauropoda incertae sedis, whereas Royo-Torres and colleagues (2006) suggested it may be referable to Turiasauria, a position maintained in their 2020 revision. It is placed at Eusauropoda incertae sedis, the least inclusive clade common to both hypotheses.

Species

Cardiodon rugulosus Owen, 1844 Nomen dubium

Type species

From Latin 'rugulosus' ('finely wrinkled'), for the wavy longitudinal ridges and finer rugae of the enamel.

Holotype
Not catalogued (lost)
Material
Isolated tooth with a crown that expands abruptly above the neck, is flattened transversely and broader anteroposteriorly, edged before and behind, and contracts to a usually abraded point; enamel roughened by wavy longitudinal ridges with finer rugae between them; fang smooth and cylindrical.
Horizon
Forest Marble Formation, Bathonian, Middle Jurassic , 168.2–165.3 million years ago
Locality
Bradford-on-Avon, Wiltshire, United Kingdom

Synonyms

  • Cetiosaurus rugulosus junior objective

    Combination coined by Steel (1970) for the original Cardiodon tooth. Cardiodon has priority, and Upchurch and Martin (2003) treat the combination as a junior objective synonym because it rests on the same type specimen.

References

  1. Owen, R. (1841). Odontography, Part II. Hippolyte Baillière.

    Erects the genus on an isolated heart-shaped tooth from the Forest Marble near Bradford, Wiltshire, referring it to an extinct crocodilian.

    owen1841b
  2. Owen, R. (1844). Odontography, Part III. Hippolyte Baillière.

    Figures the tooth in the plate descriptions and first applies the binomial Cardiodon rugulosus.

    owen1844a
  3. Upchurch, P.; Martin, J. (2003). The anatomy and taxonomy of Cetiosaurus (Saurischia, Sauropoda) from the Middle Jurassic of England. Journal of Vertebrate Paleontology 23(1): 208-231. doi:10.1671/0272-4634(2003)23[208:TAATOC]2.0.CO;2

    Rejects the synonymy with Cetiosaurus, retains the species provisionally, and identifies it as Eusauropoda incertae sedis.

    upchurch2003a
  4. Royo-Torres, R.; Cobos, A.; Alcalá, L. (2006). A Giant European Dinosaur and a New Sauropod Clade. Science 314(5807): 1925-1927. American Association for the Advancement of Science (AAAS). doi:10.1126/science.1132885

    Suggests the Cardiodon tooth may be referable to the newly named clade Turiasauria on shared crown morphology.

    royo-torres2006a
  5. Mannion, P. D. (2011). A reassessment of Mongolosaurus haplodon Gilmore, 1933, a titanosaurian sauropod dinosaur from the Early Cretaceous of Inner Mongolia, People's Republic of China. Journal of Systematic Palaeontology 9(3): 355-378. Informa UK Limited. doi:10.1080/14772019.2010.527379

    Notes the convex lingual tooth surface as unique among eusauropods other than titanosaurs.

    mannion2011b
  6. Steel, R. (1970). Saurischia. Handbuch der Paläoherpetologie 14: 1-87. steel1970a