Turrilites (Turrilites) costatus is a species of helically coiled ammonoid cephalopod, from the lower part of the Upper Cretaceous (Cenomanian).
Description The shell of this species can reach a length of about . It is tightly wound in a high trochospiral, with an acute angle at the apex. Ribs are weak, with rows of strong tubercles.
References
Arkell et al., Mesozoic Ammonoidea (L222); Treatise on Invertebrate Paleontology Part L, Ammonoidea. Geological Soc. of America and Univ Kansas Press. The Paleobiology Database Turrilites entry Ammonites