Fibulariella angulipora Mortensen, 1948

Arachchige, Gayashan M., Jayakody, Sevvandi, Mooi, Rich & Kroh, Andreas, 2019, Taxonomy and distribution of irregular echinoids (Echinoidea: Irregularia) from Sri Lanka, Zootaxa 4541 (1), pp. 1-100 : 41-44

Fibulariella angulipora Mortensen, 1948

Figures 34 , 35

1948d Fibularia (Fibulariella) angulipora Mortensen : p. 6.

1948b Fibularia (Fibulariella) angulipora Mortensen. —Mortensen: p. 224–225; pl. 46: figs. 1–4, 12–14. Material studied. Ten denuded tests: WUSL/EI/132, EI/133, EI/144, EI/145, EI/146, EI/147, EI/148, EI/149, EI/ 150, and EI/151, from Etalai, Kalpitiya, Sri Lanka.

Description. Shape and size —Test oval, rounded or pointed at both ends, small size, 3.39–7.14 mm TL, longer than broad, width 65–71% TL, height 43–53% TL; greatest height usually anterior to apical system; oral side convex; raised, rounded margin; aboral surface sloping slightly downward towards posterior end.

Apical system —Subcentral, 41–51% TL from anterior margin; four small, circular gonopores, multiple small hydropores, not in groove, scattered over anterior portion of madreporic plate.

Ambulacra —Petaloid area longer than half of TL, 66–71% TL; petaloid area width 40–46% TL; petals short, with 3–5 pore pairs in posterior paired petals, 3–4 pore pairs in anterior paired petals, 4–5 pore pairs in petal III; pores in posterior petals markedly triangular.

Peristome —Medium-sized, 15–19% TL; usually rounded, width 13–17% TL; lies slightly anterior of centre, 40–47% TL from anterior margin.

Periproct —Small, 8–9% TL; oval in outline, slightly elongate; situated closer to peristome than posterior edge, 17–23% TL from posterior margin.

Geographic range. Indo-West Pacific, from Andaman Sea ( Putchakarn & Sonchaeng 2004) to Gulf of Siam and the Molucca Sea ( Mortensen 1948b).

Bathymetric range. 15 m ( Mortensen 1948b).

Observed occurrence in Sri Lanka. The current study found only denuded tests of F. angulipora on the shore of Etalai, Kalpitiya, in north-western coasts of Sri Lanka ( Fig. 35 ).

Remarks. According to ( Mortensen 1948b: 225), this species differs from the two other Fibulariella species, F. acuta and F. oblonga , by the large, triangular pores in the petals. F. angulipora is recorded here for the first time from Sri Lanka. This supports Mortensen's (1948b: 225) suggestion that the specimen mentioned as Fibularia volva by H. L Clark (1915) was in reality Fibulariella angulipora , not Fibularia volva .

Figures

FIGURE 34. Fibulariella angulipora (WUSL/EI/164): A, aboral view; B, oral view; C, lateral view.

FIGURE 35. Distribution map of Fibulariella angulipora recorded in this study.