Subzeidora devota (Thiele, 1915)
Description: Shell oval, widest centrally. Apex backward pointing, recurved, at posterior margin. Anterior slope convex, posterior slope concave. Slit in margin, one-third of anterior slope length, narrower towards margin. Selenizone from apex to slit, edges raised, with curved costae. Sculptured with about 30 radial ribs and concentric ridges. Margin crenulate by external sculpture. Interior with a callus band around posterior half of shell, sometimes extended into a shelf occupying one-tenth of shell length. Colour white.
Size: Up to 3.5 mm in length.
Distribution: Known only from Woolgoolga to Ulladulla, NSW.
Habitat: Beach grit and down to 9 m. Uncommon.
Comparison: Related Australian species are Zeidora tasmanica (Beddome, 1882), Zeidora lodderae Tate & May, 1900 and Zeidora legrandi Tate, 1894, all from South Australia or Tasmania. These species are larger, and the internal shelf occupies from one-sixth to one-third of the shell length, while in the present species it is only a callus band. Zeidora lodderae has been recorded from NSW in Iredale & McMichael's 1962 checklist, but the record cannot be confirmed.
Fig. 1 a. Collaroy Beach, NSW (C.444197) b. Fingal Bay, NSW (C.444199) c. Woolgoolga, NSW (C.444198) (SEM photos Sue Lindsay)
Copyright Des Beechey 2005