Sinotitinae is one of three subfamilies of the Dimeroceratidae; a member of the Goniatitida, an extinct order of ammonoid cephalopods from the Paleozoic.
The two comprised genera, Sinutites and Sunites have broad, crescent shaped whorl sections, but one, Sinutites has a dorsal siphuncle while in the other, Sunites the siphuncle is ventral.
References Sinotitinae entry on the Paleobiology Database 5/26/12