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 sp. Figures 27 , 32 , 33 Material studied. Eleven denuded tests: WUSL/EI/158, EI/159, EI/161, EI/164, EI/165, EI/179, EI/180, EI/181, EI/185, EI/186, and EI/187, from Hiriketiya Bay, Sri Lanka . Description. Shape and size —Test oval, small, 5.3–8.72 mm TL, longer than broad, width 75–84% TL, height 44–50% TL, posterior part of test wider than anterior, test slightly pointed anteriorly and truncated posteriorly; oral side slightly concave. Apical system —Situated posterior of centre, 53–59% TL from anterior margin; with four circular small gonopores and small hydropores placed in short groove ( Fig. 33 , A). Ambulacra —Petaloid area 69–76% TL, petaloid width 47–49% TL; petals short, with 5–8 pore pairs in each series of petal III and posterior 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 similar in width to poriferous zones. Peristome —Moderate in size, length 16–22% TL; rounded pentagonal, width 12–17% TL, situated slightly anterior of centre, 39–43% TL from anterior margin. Periproct —Small, length 11–12% TL; squarish in outline; slightly elongate, width 8–11% TL; situated closer to peristome than posterior edge, 16–22% TL from posterior margin, four plates on periproctal membrane, no spines on plates. Observed occurrence in Sri Lanka . Denuded tests only were found on the beach of Hiriketiya Bay, southern coast of Sri Lanka ( Fig. 27 ). Remarks. This taxon likely represents a new species currently under study by one of us (Rich Mooi). Fibularia sp. can be distinguished from F. cribellum , F. japonica , F. plateia , and F. nutriens in having higher numbers of pore pairs relative to TL. This species is very similar to F. ovulum as both have a relatively high number of pore pairs. However, Fibularia sp. can be consistently distinguished from F. ovulum by its lower test.