Although it spent its entire life in the ocean, Tinirau is a stem tetrapod close to the ancestry of land-living vertebrates in the crown group Tetrapoda.

The lengthening of the glenoid corresponds with a flattening of the proximal end of the humerus, a feature common in the forelimbs of more advanced stem tetrapods.

They came from a deposit called the Red Hill I beds, which date to the upper Givetian stage of the Middle Devonian.

The Red Hill I beds include a series of limestone and mudstone, likely deposited in an outer continental shelf marine environment.

The specific name honors Jennifer A. Clack, an English paleontologist who has made many contributions to the study of stem tetrapods.

Below is a cladogram modified from Swartz (2012) showing the placement of Tinirau:[2] Kenichthys Rhizodontidae Marsdenichthys Canowindra Koharalepis Beelarongia Gogonasus Gyroptychius Osteolepis Medoevia Megalichthyidae Spodichthys Tristichopterus Eusthenopteron Jarvikina Cabonnichthys Mandageria Eusthenodon Tinirau Platycephalichthys Panderichthys Tiktaalik Elpistostege Elginerpeton Ventastega Acanthostega Ichthyostega Whatcheeriidae Colosteidae Crassigyrinus Baphetidae Total-group Lissamphibia Embolomeri Other stem amniotes On the other hand, Parfitt et al. (2014) considered it more likely that Tinirau was a member of the family Tristichopteridae.