Orthoseira hawaiiensis Danz & Kociolek. LM (A–D) and SEM (E–M) micrographs taken from sample 110 (Karkar Island, Village of Mom, Papua New Guinea). A–D. LM pictures of valves in valve face view. E. SEM external view of a valve in oblique view showing the step in the mantle, the marginal ring of spines and the valve face ornamentation. F. Frustule in girdle view showing the structure of the cingulum. G. SEM detailed view of linking spines and mantle structure. H–I. SEM external view of a valve face. J. SEM external detail of denser grouping of short and longer ridges between areolae on the valve face. K. Internal view of a complete valve. L. SEM internal detail of the carinoportulae. M. External view of valvocopula. Scale bars: A–I, K, M = 10 µm; J, L = 2 µm.