Small, subcircular, smooth, gently biconvex, anterior
commissure rectimarginate; beak ridges slightly tuberculate; foramen large, hypothyrid, deltidial plates very narrow, disjunct, pedicle collar short;
hinge teeth with small recessive dental plates. No cardinal process; high inner socket ridges with long crura that are anteromedially convergent; septal pillar platelike at its base with high, narrow distal extremity (axial loop phase), descending branches absent.
Lophophore zygolophous and heavily spiculate.
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