Taxonomy and distribution of irregular echinoids (Echinoidea: Irregularia) from Sri Lanka Author Arachchige, Gayashan M. Author Jayakody, Sevvandi Author Mooi, Rich Author Kroh, Andreas text Zootaxa 2019 2019-01-03 4541 1 1 100 journal article 27715 10.11646/zootaxa.4541.1.1 9c3fecf1-4e11-4c79-a908-e0a5abbaf3ca 1175-5326 2617460 B11E734C-218B-418C-84E6-719AB3C58AFF 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. FIGURE 29. SEM images showing test characters of Fibularia ovulum : A, apical system (WUSL/EI/178); B, internal view (WUSL/EI/171). FIGURE 30. Comparison of test height of Fibularia ovulum (A, WUSL/EI/178) and Fibularia sp. (B, WUSL/EI/164). 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 ).