Noasaurids were also nimble and lightly built, with feet showing adaptations for running such as a long central foot bone (metatarsal III).

[3] A collection of features which characterize noasaurids in particular has been compiled by Rauhut & Carrano (2016), who included controversial taxa such as Deltadromeus and the elaphrosaurines within Noasauridae.

The hooked rear edge of the coracoid region is also offset from the glenoid (shoulder socket) by a large U-shaped notch.

The humerus (upper arm bone) was thin and straight, with a low and somewhat rounded humeral head (the portion which attached to the shoulder).

In contrast, abelisaurids had a large and bulbous humeral head (although similarly rounded) while that of other theropods was flattened from front to back.

[8] In addition, the two subfamilies have a metatarsal II (the foot bone connected to the innermost major toe) which was flattened from the side.

[3] Many noasaurids are only known from vertebrae, including both valid (Laevisuchus, Spinostropheus) and dubious (Composuchus, Jubbulpuria, Ornithomimoides, Coeluroides) genera.

Rauhut & Carrano (2016) define Noasaurinae as "all noasaurids more closely related to Noasaurus than to Elaphrosaurus, Abelisaurus, Ceratosaurus, or Allosaurus".

In 2016, a redescription of Elaphrosaurus by Oliver Rauhut and Matthew Carrano argued against earlier hypotheses that elaphrosaurines were basal ceratosaurs, instead placing them alongside noasaurines within a monophyletic Noasauridae.

This study formally defined Elaphrosaurinae as "all noasaurids more closely related to Elaphrosaurus than to Noasaurus, Abelisaurus, Ceratosaurus, or Allosaurus".

However, juvenile Limusaurus specimens retained teeth and lacked these signs of herbivory, meaning that young elaphrosaurines may have been more capable of a carnivorous or omnivorous diet.

Members of this genus could grow up to 20 feet (6.1 meters) long, although they were significantly lighter than similarly sized carnivorous contemporaries such as Ceratosaurus.

Carnosaurs, megalosauroids, coelurosaurs, and most other ceratosaurians (including noasaurines) all have vertebrae which have front faces ranging from very weakly concave to flat (platycoelous) or convex (opisthocoelous).

[3] In 2020 a middle cervical vertebra from the lower Albian Eumeralla Formation of Cape Otway, Victoria, Australia was referred to Elaphrosaurinae.

[11][12] The following cladogram is based on the phylogenetic analysis conducted by Rauhut and Carrano in 2016, showing the relationships among the Noasauridae:[3] Abelisauridae Laevisuchus Deltadromeus Limusaurus

[13][3] Deltadromeus is a particularly controversial genus, as it shares many features with noasaurids but is also very similar to Gualicho, which has been classified as a close relative of the enigmatic (but generally considered non-ceratosaurian) megaraptorans.

The structure of Noasauridae changed greatly depending on the age of the Limusaurus specimens, although Genusaurus and Deltadromeus were resolved as noasaurids in each diagnosis.

[15] Kryptops (postcranium) Elaphrosaurinae Ceratosauridae Berberosaurus Eoabelisaurus Ligabueino Berthasaura Afromimus Austrocheirus Noasauridae Abelisauridae