Fibularia ovulum Lamarck, 1816

Figures 27, 28–31

1816 Fibularia ovulum Lamarck: p. 17.

1948b Fibularia ovulum Lamarck. —Mortensen: p. 208–212; pl. 46: figs. 48–50, 21–24.

Ambulacra —Petaloid area 61–74% TL, petaloid width 42–51% TL; petals short, with 4–7 pore pairs in each series of petal III and posterior paired petals, 3–5 pore pairs in each series of anterior paired petals; pores small rounded, petals broad, open distally; pore series slightly diverging; interporiferous zones smaller than poriferous zones.

Peristome —Moderate in size, diameter 17–21% TL; rounded pentagonal, width 12–17% TL, situated slightly anterior of centre, 37–42% TL from anterior margin of test.

Periproct —Small, 9–13% TL; squarish in outline; slightly elongate, width, 8–11% TL; situated closer to peristome than posterior edge, 17–26% TL from posterior margin of test.

Geographic range. Indo-West Pacific, from the Red Sea (Clark 1925a; Mortensen 1948c) to Coral Sea (Miskelly 2002) and the Philippines (Mortensen 1948b).

Bathymetric range. Intertidal zone to 385 m (Mortensen 1948b).

Observed occurrence in Sri Lanka. Denuded tests only were found on the beach of Hiriketiya Bay, southern coast of Sri Lanka (Fig. 27).

Remarks. Fibularia ovulum differs from Fibularia sp. in having a higher test (Fig. 30). Test height of Sri Lankan Fibularia ovulum is relatively low compared to specimens from the Maldives. However, the total petaloid pore pair number overlaps with that of with Fibularia sp. (Fig. 31).