Prorsisphinctes is a middle Jurassic ammonite included in the perisphictid subfamily Leptosphinctinae. Shells are evolute with whorls somewhat overlapping and strongly ribbed. Ribs on the lower flanks of Prorsisphinctes meseres, found in France, are large and wide spaced and divide about mid flank, resulting in more numerous, narrower ribs on the outer flanks and venter.