Hippopodina feegeensis (Busk, 1884)

Fig. 15 A–C

Lepralia feegeensis Busk, 1884: 144, pl. 22, fig. 9, 9a, 9b.

Hippopodina feegeensis – Tilbrook 1999: 451, fig. 1a–h.

Material

MALAYSIA: MSL BRY001b, Pantai Pasir Hitam, Langkawi, collected intertidally from coral reef.

Description

Colony encrusting, multiserial, unilamellar or multilamellar, often large in size; growing edge revealing line of buttressed pores in transverse walls. Ancestrula and early astogeny not observed in studied Malaysian material; elsewhere ancestrula comprising a tetrad of zooids (e.g., Tilbrook 1999: fig. 1b). Autozooids large, 0.75–1.00 mm long by 0.42–0.58 mm wide, subrectangular to subhexagonal; distinct with interzooidal grooves; frontal shield gently convex, perforated by numerous small, closely spaced pores, pustulose; orifice large, hoof-shaped, almost equidimensional, 0.20–0.22 mm long by 0.18–0.20 mm wide, proximal edge gently concave, wide, condyles rounded, lateral; ovicell large (Fig. 15B), 0.46–0.50 mm long by 0.44–0.50 mm wide, evenly porous, calcification resembling frontal shield but lacking pustules, primary orifice of ovicellate zooids a little larger than in non-ovicellate zooids, secondary orifice broad, 0.12 mm long by 0.24 mm wide, incipient ovicell evident as a sparsely porous, smooth depression in proximal gymnocyst of distal zooid. Adventitious avicularia (Fig. 15C) present in less than one-half of autozooids, singly or paired, 0.18–0.26 mm long by 0.12–0.16 mm wide; located distolaterally of orifice, directed transversely towards midline of supporting autozooid; rostrum a high triangle with slightly concave sides, pointed distally; cross-bar calcified in most, straight; opesia semicircular.

Remarks

This is a common species circumtropically, often occurring in coral reefs, which is widely distributed in the Pacific, Indian and Atlantic Oceans and also recorded from the Mediterranean and Red Seas (see Powell 1969: fig. 2). The large sizes of both the colonies and their constituent zooids are notable.

Colonies of this species found at Pantai Pasir Hitam, Langkawi were remarkable for being concentrated in a small area and absent from similar-looking habitats in the area. This suggests localized recruitment, perhaps from a single founding colony.