Bathyotica is a

clade In biology, a clade (), also known as a Monophyly, monophyletic group or natural group, is a group of organisms that is composed of a common ancestor and all of its descendants. Clades are the fundamental unit of cladistics, a modern approach t ...

crurotarsan Crurotarsi is a clade of archosauriformes, archosauriform reptiles that includes crocodilians and stem-crocodilians and possibly bird-line Archosaur, archosaurs too if the extinct, crocodile-like phytosaurs are more distantly related to crocodile ...

archosaur Archosauria () or archosaurs () is a clade of diapsid sauropsid tetrapods, with birds and crocodilians being the only extant taxon, extant representatives. Although broadly classified as reptiles, which traditionally exclude birds, the cladistics ...

s that includes the superorder

Crocodylomorpha 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. Extinct crocodylomorphs were considerably mor ...

and its

sister taxon In phylogenetics, a sister group or sister taxon, also called an adelphotaxon, comprises the closest relative(s) of another given unit in an evolutionary tree. Definition The expression is most easily illustrated by a cladogram: Taxon A and ...

'' Erpetosuchus'', a small

Triassic The Triassic ( ; sometimes symbolized 🝈) is a geologic period and system which spans 50.5 million years from the end of the Permian Period 251.902 million years ago ( Mya), to the beginning of the Jurassic Period 201.4 Mya. The Triassic is t ...

suchia Suchia (from Ancient Greek σούχος (''soúkhos''), meaning "crocodile") is a clade of archosaurs containing the majority of pseudosuchians (crocodilians and their extinct relatives). It was defined as the least inclusive clade containing ''A ...

n. Bathyotica was named in a 2002

phylogenetic In biology, phylogenetics () is the study of the evolutionary history of life using observable characteristics of organisms (or genes), which is known as phylogenetic inference. It infers the relationship among organisms based on empirical dat ...

study of ''Erpetosuchus''. The genus was found to be closely related to crocodylomorphs, and Bathyotica was erected to encompass both taxa. Bathyotica has several

apomorphies In phylogenetics, an apomorphy (or derived trait) is a novel character or character state that has evolved from its ancestral form (or plesiomorphy). A synapomorphy is an apomorphy shared by two or more taxa and is therefore hypothesized to hav ...

, characteristics that distinguish it from more basal crurotarsans. A prominent feature is the forward sloping of the quadrate and

quadratojugal The quadratojugal is a skull bone present in many vertebrates, including some living reptiles and amphibians. Anatomy and function In animals with a quadratojugal bone, it is typically found connected to the jugal (cheek) bone from the front and ...

bones at the back of the skull. The sloping bones open up a space called the otic recess, which is positioned behind the lower temporal fossa, a hole on the side of the skull behind the eye sockets. Members of Bathyotica also lack a

postfrontal The postfrontal is a paired cranial bone found in many tetrapods. It occupies an area of the skull roof between and behind the orbits (eye sockets), lateral to the frontal and parietal bones, and anterior to the postorbital bone. The postfrontal ...

bone. In 2012, the genus '' Parringtonia'' was redescribed and found to be closely related to ''Erpetosuchus''. Both were united in the family Erpetosuchidae. However, the

analysis in that paper resulted in Erpetosuchidae being part of a

polytomy An internal node of a phylogenetic tree is described as a polytomy or multifurcation if (i) it is in a rooted tree and is linked to three or more child subtrees or (ii) it is in an unrooted tree and is attached to four or more branches. A tree ...

with the two main branches of Archosauria,

Pseudosuchia Pseudosuchia, from Ancient Greek ψεύδος (''pseúdos)'', meaning "false", and σούχος (''soúkhos''), meaning "crocodile" is one of two major divisions of Archosauria, including living crocodilians and all archosaurs more closely relat ...

and

Avemetatarsalia Avemetatarsalia (meaning "bird metatarsals") is a clade of diapsid Reptile, reptiles containing all archosaurs more closely related to birds than to crocodilians. The two most successful groups of avemetatarsalians were the dinosaurs and pterosau ...

, a distant position from Crocodylomorpha. However, this placement was uncertain and the exact phylogenetic position of ''Erpetosuchus'' remains unclear because it possesses many

autapomorphies In phylogenetics, an autapomorphy is a distinctive feature, known as a derived trait, that is unique to a given taxon. That is, it is found only in one taxon, but not found in any others or outgroup taxa, not even those most closely related to ...

or unique features that are not seen in other archosaurs. Nevertheless, a sister-taxon relationship between Erpetosuchidae and Crocodylomorpha required 13 extra steps in their analysis, making it very improbable. Even when ''Erpetosuchus granti'' was solely used to represent Erpetosuchidae, it was recovered as the sister taxon of

aetosaur Aetosaurs () are heavily armored reptiles belonging to the extinct order (biology), order Aetosauria (; from Ancient Greek, Greek, (aetos, "eagle") and (, "lizard")). They were medium- to large-sized Omnivore, omnivorous or Herbivore, herbivor ...

s + '' Revueltosaurus'', at the base of

Suchia Suchia (from Ancient Greek σούχος (''soúkhos''), meaning "crocodile") is a clade of archosaurs containing the majority of pseudosuchians (crocodilians and their extinct relatives). It was defined as the least inclusive clade containing ''A ...

References

{{Taxonbar, from=Q4869200 Pseudosuchia Extant Late Triassic first appearances