Cardiodon

*Cardiodon rugulosus*

**Cardiodon** is a Primitive Sauropodis the only known species of the extinct Cardiodon genus of turiasaurian sauropod dinosaur, which lived in the from Middle Jurassic England, approximately 167 million years ago, in the Bathonian, in what is today Europe. Known from a single tooth, sometimes considered as coming from Cetiosaurus. A new study of Cetiosaurus showed that the tooth was distinct from Cardiodon.

## Description

Cardiodon is only known from its teeth, but a probable size of 16 meters long has been speculated. The teeth differ from those of Cetiosaurus , because it has a convex lingual surface. The original tooth shows, as far as can be deduced from surviving illustrations, the rare combination of being spatulate and having a convex inner side, although the convexity is slight. Its crown is short and wide, slightly curved inwards. The outer side is strongly convex curved from front to back. A shallow groove is present on this side, parallel to the rear edge. The crown tapers towards its tip. The edges do not have denticles. The glaze shows the small wrinkles that the specific name refers to.
The cardiodon was found in Forest Marble, Wiltshire, in the Great Oolite Formation, near Gloucestershire, England. Sir Richard Owen named the genus from teeth found near Bradford-on-Avon, but did not assign a species to it until a few years later. Richard Owen named the genus for a now lost tooth, part of the collection by naturalist Joseph Chaning Pearce, found near Bradford-on-Avon, but was not assigned a specific name at the time. The generic name is derived from the Greek καρδία , kardia , "heart", and ὀδών , odon , "tooth", in reference to its heart-shaped profile. A few years later, in 1844, he added the specific name rugulosus , which It means "wrinkled" in Latin. Cardiodon was the first sauropod to be given a formal name, although Owen was at the time completely unaware of the sauropod nature of the find.
After its discovery, both Owen and others speculated on the possibility that it is a synonym for the better-known Cetiosaurus . Richard Lydekker formalized this view by assigning it to Cetiosaurus oxoniensis in 1890 on the basis of teeth found in Oxfordshire associated with a skeleton of C. oxoniensis . A second tooth appeared in, BMNH R1527 , from Great Oolite near Cirencester, Gloucestershire. Cardiodon has generally been assigned to Cetiosaurus , sometimes as a separate species, Cetiosaurus rugulosus , despite its priority.
Historically, it is very obscure and generally refers to Cetiosaurus , but recent analyzes suggest that it is a distinct genus, and possibly related to Turiasaurus . Cardiodon was the first genus of sauropod to be named. In 2003, Paul Upchurch and John Martin, reviewed Cetiosaurus , and found little evidence assigning the teeth to the skeleton of C. oxoniensis , and that the teeth of " C. oxoniensis " differ of those of Cardiodon ; From these they contributed the idea that Cardiodon should be restored as its own genus. Upchurch et al. In 2004 they reviewed what was known and found that the teeth of Cardiodon present autapomorphies, with those of eusauropods. More recently, Royo-Torres et al. (2006), in their description of Turiasaurus , place Cardiodon as a possible relative of the new giant. Previously, Cardiodon had usually been assigned to the Cetiosauridae or its own family Cardiodontidae .