Named by Dumitrica, Gorican & Hori.
Diagnosis: Eucyrtidiellum with numerous thin, longitudinal abdominal costae and a row of pores in each intercostal depression.
Original description: Test composed of four segments of which only the first three are completely preserved. Cephalis integrated into the proximal part of the long, stout conical apical horn and visible as a slightly inflated portion at the base of the latter. Diameter of horn at base the same as cephalis, decreasing progressively to the sharp tip. Thorax small, truncate conical with convex sides and numerous small pores disposed irregularly. Abdomen wide, subglobular and porous; pores circular aligned in longitudinal rows, each row separated by thin costae. Fourth segment preserved only as remains.
Original remarks: The species is very rare and is described based on 3 specimens only. E. omanojaponicum n. sp. resembles E. nagaiae n. sp. in having longitudinal abdominal costae, but the costae are weaker and separated by a single row of pores whereas E. nagaiae has 2-4 rows of pores in the intercostal intervals.
Etymology: From its occurrence in Oman and Japan.