''Phyllodontosuchus'' (

Ancient Greek Ancient Greek includes the forms of the Greek language used in ancient Greece and the ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Dark Ages (), the Archaic p ...

, meaning "leaf tooth crocodile", in reference to the shape of the middle and posterior teeth) is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...

sphenosuchia Sphenosuchia is a suborder of basal crocodylomorphs that first appeared in the Triassic and occurred into the Middle Jurassic. Most were small, gracile animals with an erect limb posture. They are now thought to be ancestral to crocodyliforms, ...

n, a type of basal

crocodylomorph Crocodylomorpha is a group of pseudosuchian archosaurs that includes the crocodilians and their extinct relatives. They were the only members of Pseudosuchia to survive the end-Triassic extinction. During Mesozoic and early Cenozoic times, cro ...

, the clade that comprises the

crocodilia Crocodilia (or Crocodylia, both ) is an order of mostly large, predatory, semiaquatic reptiles, known as crocodilians. They first appeared 95 million years ago in the Late Cretaceous period ( Cenomanian stage) and are the closest livi ...

ns and their closest kin. It is known from a skull and jaws from

Lower Jurassic The Early Jurassic Epoch (in chronostratigraphy corresponding to the Lower Jurassic Series) is the earliest of three epochs of the Jurassic Period. The Early Jurassic starts immediately after the Triassic-Jurassic extinction event, 201.3 Ma&nb ...

rocks of

Yunnan Yunnan , () is a landlocked province in the southwest of the People's Republic of China. The province spans approximately and has a population of 48.3 million (as of 2018). The capital of the province is Kunming. The province borders the C ...

, China. ''Phyllodontosuchus'' is unusual because some of its teeth were leaf-shaped, like those of some

herbivorous A herbivore is an animal anatomically and physiologically adapted to eating plant material, for example foliage or marine algae, for the main component of its diet. As a result of their plant diet, herbivorous animals typically have mouthpar ...

dinosaur Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the evolution of dinosaurs is t ...

s, and it does not appear to have been a strict

carnivore A carnivore , or meat-eater (Latin, ''caro'', genitive ''carnis'', meaning meat or "flesh" and ''vorare'' meaning "to devour"), is an animal or plant whose food and energy requirements derive from animal tissues (mainly muscle, fat and other s ...

like most other crocodylomorphs.

History and description

''Phyllodontosuchus'' is based on BVP568-L12, a crushed skull and jaws recovered from the

Sinemurian In the geologic timescale, the Sinemurian is an age and stage in the Early or Lower Jurassic Epoch or Series. It spans the time between 199.3 ± 2 Ma and 190.8 ± 1.5 Ma (million years ago). The Sinemurian is preceded by the Hettangian and ...

-age Dark Red Beds of the

Lufeng Formation The Lufeng Formation (formerly Lower Lufeng Series) is a Lower Jurassic sedimentary rock formation found in Yunnan, China. It has two units: the lower Dull Purplish Beds/Shawan Member are of Hettangian age, and Dark Red Beds/Zhangjia'ao Member ar ...

near Dawa in Yunnan. A '' Morganucodon'' skull was also recovered from this locality. BVP568-L12 is only long and imperfectly preserved; it was first thought to represent an early ornithischian 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. The

type species In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specime ...

is ''P. lufengensis'', in reference to the Lufeng Formation. There were 17 or 18 teeth per side in the upper jaw, which differed in

shape A shape or figure is a graphical representation of an object or its external boundary, outline, or external surface, as opposed to other properties such as color, texture, or material type. A plane shape or plane figure is constrained to lie ...

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 some

prosauropod Sauropodomorpha ( ; from Greek, meaning "lizard-footed forms") is an extinct clade of long-necked, herbivorous, saurischian dinosaurs that includes the sauropods and their ancestral relatives. Sauropods generally grew to very large sizes, had l ...

s and early ornithischians, but differ in important features. For example, the teeth lacked the swellings and ridges seen in the teeth of early ornithischians like ''

Lesothosaurus ''Lesothosaurus'' is a Monotypic taxon, monospecific genus of ornithischian dinosaur that lived during the Early Jurassic in what is now South Africa and Lesotho. It was named by paleontologist Peter Galton in 1978, the name meaning "lizard from L ...

'', and the coarse denticles (smaller points) of leaf-shaped ornithischian and prosauropod teeth in general. ''Phyllodontosuchus'' also lacked a

predentary Ornithischia () is an extinct order of mainly herbivorous dinosaurs characterized by a pelvic structure superficially similar to that of birds. The name ''Ornithischia'', or "bird-hipped", reflects this similarity and is derived from the Greek st ...

as found in all known ornithischians. Instead, it is most similar to sphenosuchians. Heterodonty is known in several sphenosuchians, including ''

Dibothrosuchus ''Dibothrosuchus'' is a genus of sphenosuchian, a type of basal crocodylomorph, the clade that comprises the crocodilians and their closest kin. It is known from several partial skeletons and skulls. These fossils were found in Lower Jurassic ...

'', '' Hesperosuchus'', ''

Pedeticosaurus ''Pedeticosaurus'' is an extinct genus of crocodylomorph from the Clarens Formation (Early Jurassic) of South Africa. The type species ''Pedeticosaurus leviseuri'' was named by Egbert Cornelis Nicolaas van Hoepen in 1915 on the basis of a mold ...

'', and ''

Sphenosuchus ''Sphenosuchus'' ("wedge crocodile") is an extinct genus of crocodylomorph from the Early Jurassic Elliot Formation of South Africa, discovered and described early in the 20th century. The skull is preserved very well but other than elements of ...

''. 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 of ''Phyllodontosuchus''. Small heterodont crocodylomorphs are known from other lineages as well, including ''

Edentosuchus ''Edentosuchus'' is a genus of protosuchian crocodylomorph. It is known from fossils found in rocks of the Early Cretaceous-age Tugulu Group from the Junggar Basin, Xinjiang, China. Two partial skulls and several neck vertebrae are known to ...

'', '' Chimaerasuchus'', and '' Malawisuchus''. These small, variably-toothed crocodylomorphs are thought to have had diets beyond the typical carnivory/

piscivory A piscivore () is a carnivorous animal that eats primarily fish. The name ''piscivore'' is derived . Piscivore is equivalent to the Greek-derived word ichthyophage, both of which mean "fish eater". Fish were the diet of early tetrapod evolut ...

of modern crocodilians, possibly including some degree of herbivory. If ''Phyllodontosuchus'' did eat plants, it probably did not grind them in the jaws, though.

Notes

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.

References

{{Taxonbar, from=Q7188818 Early Jurassic reptiles of Asia Early Jurassic crocodylomorphs Prehistoric pseudosuchian genera