The holotype of Eutretauranosuchus delfsi was discovered by Edwin Delfs in 1957 among remains recovered from the Morrison Formation in Canon City, Colorado.

[1] Mook also described an additional, smaller opening located anterior to the internal nares, divided by the palatine processes, which was hypothesized to have entered the narial passage.

[3] Characteristics of E. delfi skulls include an elongated and platyrostral skull, posterolateral depressions on the alveolar maxillary process, minimal lateral undulation of the tooth row (maxillary), broadened nasals located anteriorly to the prefrontals, a lack of contact between the nasals and external nares, a flattened and broad innerfenestral bar with rims that are raised along the supratemporal fenestra, and a nasopharyngeal septum formed by the anterior divergence of the vomeral processes.

[4] While the majority of Goniopholididae have historically been categorized by flattened snouts and posterolaterally located maxillary depressions, there remains great variation within their palatal anatomy.

North American goniopholidids have maxillae and palatines that do not contact, resulting in a more open palate and a ventrally exposed bony nasopharyngeal passage.

[7] The size and length of Goniopholididae specimens found in the Morrison Formation, as well as striated teeth,[1] support the hypothesis that Eutretauranosuchus were carnivorous, feeding on prey such as insects, fish, small reptiles, mammals and dinosaurs.

Phylogenetic analysis by Smith et al. in 2010[2] provides evidence that Eutretauranosuchus, Calsoyasuchus and Sunosuchus are closely related, and these findings are widely supported.

However, while many publications support the phylogenetic placement of Eutretauranosuchus within the family of Goniopholididae, there is debate over whether it is more closely related to Goniopholis or Sunosuchus.

Alternatively, phylogenetic assessment by J.R. Foster in 2006 considers Eutretauranosuchus to be most closely related to Pholidosaurus and dyrosauridae, and belonging to a larger clade that includes Bernissartia, Eusuchians and Goniopholis.