Hippopodina feegeensis (Busk, 1884)

(Fig. 127; Table 27)

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

Hippopodina feegeensis: Harmer, 1957: 974, pl. 67, figs 8–9; Ryland & Hayward, 1992: 256, fig. 17a; Tilbrook, 1999: 451, fig. 1a–h; Di Martino & Taylor, 2015: 31, pl. 27.

Figured material. RGM.1350575, Holocene, UPGG 041, off South Sulawesi.

Description. Colony encrusting, multiserial, unilaminar. Autozooids distinct, bordered by interzooidal furrows, polygonal, about 560 µm long by 615 µm wide (mean L/W = 0.91). Frontal shield convex, tuberculate, evenly perforated by numerous small pseudopores, 8–14 µm in diameter, except around the orifice. Orifice hoofshaped, almost as long as wide, raised; a pair of small rounded condyles directed medially, separating a rounded anter from a shallow, bowl-shaped poster with straight proximal margin. Adventitious avicularia paired, located distolaterally of orifice and oriented medially; rostrum triangular, pointed and raised; crossbar complete. Ooecium not observed. Pore-chamber windows numerous, closely spaced, visible on the basal vertical walls of zooids; transversely oval, small, about 15 µm long by 25 µm wide.

Remarks. A small fragment with a single complete zooid of Hippopodina feegeensis was found in our samples. This circumtropical, shallow-water species generally forms very extensive sheets on many kinds of substrates. Geographical and/or habitat-related morphological variations have been observed regarding the zooidal size and the shape of the proximal orificial margin (Tilbrook 1999). Although based on a single zooid, the zooidal length of this specimen is much smaller than specimens of the supposedly same species from the Miocene of East Kalimantan (0.56 vs 0.81 mm) (Di Martino & Taylor 2015), and almost half the size of Recent specimens from Australia, the Philippines and the Red Sea (Tilbrook 1999). Although lacking in this specimen, ooecia of all Hippopodina species are very large, globular and evenly perforated (Tilbrook 2006).

N, Number of colonies and number of zooids measured; SD, standard deviation.