| Phyllodontosuchus Temporal range:Early Jurassic | |
|---|---|
Scientific classification | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Reptilia |
| Clade: | Archosauria |
| Clade: | Pseudosuchia |
| Clade: | Crocodylomorpha |
| Genus: | †Phyllodontosuchus Harriset al., 2000 |
| Species: | †P. lufengensis |
| Binomial name | |
| †Phyllodontosuchus lufengensis Harriset al., 2000 | |
Phyllodontosuchus (Ancient Greek, meaning "leaf tooth crocodile", in reference to the shape of the middle andposterior teeth) is agenus ofsphenosuchian, a type ofbasalcrocodylomorph, theclade that comprises thecrocodilians and their closest kin. It is known from a skull and jaws fromLower Jurassic rocks ofYunnan,China.Phyllodontosuchus is unusual because some of its teeth were leaf-shaped, like those of someherbivorousdinosaurs, and it does not appear to have been a strictcarnivore like most other crocodylomorphs.
Phyllodontosuchus isbased onBVP568-L12, a crushed skull and jaws recovered from theSinemurian-age Dark Red Beds of theLufeng Formation near Dawa in Yunnan. AMorganucodon skull was also recovered from this locality. BVP568-L12 is only 71.4 millimetres (2.81 in) long and imperfectly preserved; it was first thought to represent an earlyornithischian dinosaur. Sutures are not visible, so despite the small size, the specimen appears to have come from an adult.Phyllodontosuchus was named in 2000 by Jerald Harris and colleagues. Thetype species isP. lufengensis, in reference to the Lufeng Formation.[1]
There were 17 or 18 teeth per side in the upper jaw,* which differed inshape depending on where they were in the jaw (heterodonty). The first five or six were pointed, conical, and curved backward. The following twelve were leaf- or spade-shaped, with fine crenelations on the trailing edge. These are similar to the teeth of someprosauropods and early ornithischians, but differ in important features. For example, the teeth lacked the swellings and ridges seen in the teeth of early ornithischians likeLesothosaurus, and the coarse denticles (smaller points) of leaf-shaped ornithischian and prosauropod teeth in general.Phyllodontosuchus also lacked apredentary as found in all known ornithischians. Instead, it is most similar to sphenosuchians.[1]
Heterodonty is known in several sphenosuchians, includingDibothrosuchus,Hesperosuchus,Pedeticosaurus, andSphenosuchus. These forms had similar divisions of pointed and recurved anterior teeth and less pointed middle and posterior teeth, which could have been the ancestral state for the leaf-shaped teeth ofPhyllodontosuchus. Small heterodont crocodylomorphs are known from other lineages as well, includingEdentosuchus,Chimaerasuchus, andMalawisuchus. These small, variably-toothed crocodylomorphs are thought to have had diets beyond the typical carnivory/piscivory of modern crocodilians, possibly including some degree of herbivory. IfPhyllodontosuchus did eat plants, it probably did not grind them in the jaws, though.[1]
^ * The tooth count in the abstract and diagnosis is 6 conical teeth and 12 leaf-shaped teeth, while the body of the paper describes a total of 17 teeth per side, ?5 of which are conical.
