ABSTRACT
Three ophiuroid faunules are recorded from strata of mid-to Late Cretaceous age in Shikoku (southwest Japan). In Ehime Prefecture, the Furushiroyama Formation (Santonian) has yielded amphiurids, ?ophiothricids and a new ophiurid (Ophiura [s. lat.] sp. nov.; dorsal view. Disc diameter: 7mm; teeth are small and pointed; oral plates rectangular; dorsal arm plates trapezoidal; lateral arm plates well developed), while at Kochi (Kochi Prefecture), deposits assigned to the Monobegawa Group (Aptian-Albian) have produced a new ophiurid and ophiolepidid (Ophiomusium sp. nov.; dorsal view. Disc diameter: 13 mm; oral slits very narrow; radial shields and interradial disc scales large; arms stout; lateral arm plates in contact on dorsal side). The third lot, from the Kajisako Formation (middle Turonian-lower Campanian) at Kajisako in Kochi Prefecture, comprises a new ophiochitonid (Ophiochiton? sp. nov.; dorsal view. Disc diameter: 10.7mm; disc circular in outline; radial shields large, in contact; lateral arm plates in contact on dorsal side; dorsal arm plates small, triangular; arm spines equalling half the length of arm segments, appressed). Making matters worse in our study of these faunules is the pervasive calcite dissolution, which left only iron oxide-coated external moulds in a fine-grained sandstone or mudstone. Silicone rubber casts and peels were made of all specimens, so as to study disc/arm plating and mouth structure, as preserved. Cretaceous ophiuroids are well known from the Cenomanian and Campanian-Maastrichtian from Europe, but the record from elsewhere in the world is patchy. The Shikoku specimens add significantly to our knowledge of Cretaceous ophiuroids.
