Rhinosteus is an extinct genus of small to medium selenosteid arthrodire placoderms of the Late Devonian known from the Upper Frasnian Kellwasserkalk facies of Bad Wildungen, Germany[1] and Morocco.

[2] Rhinosteus is a typical genus of Kellwasserkalk selenosteids, with short cheeks, and slender inferognathal (lower jaw) plates.

In R. traquairi, the rostrum is sharply pointed, extending beyond the snout, and the tubercles are small and irregularly placed.

The species R. parvulus has a blunt rostrum that does not extend beyond the snout, and lacks tuberculation altogether.

The cladogram below shows the phylogeny of Rhinosteus:[3] Coccosteomorphi Rhachiosteus pterygiatus Eastmanosteus calliaspis Eastmanosteus pustulosus Kiangyousteus yohii Golshanichthys asiatica Westralichthys uwagedensis Dunkleosteus raveri Dunkleosteus terrelli Dunkleosteus amblyodoratus Heterosteus ingens Yinosteus major Tapinosteus heintzi Bullerichthys fascidens Kendrickichthys cavernosus Bruntonichthys multidens Dinichthys herzeri Hadrosteus rapax Gorgonichthys clarki Heintzichthys gouldii Pachyosteus bulla Gymnotrachelus hydei Stenosteus angustopectus Brachyosteus dietrichi Melanosteus occitanus Rhinosteus parvulus