Hippopodina feegeensis ( Busk, 1884 )

Martino, Emanuela Di & Taylor, Paul D., 2018, Early Pleistocene and Holocene bryozoans from Indonesia, Zootaxa 4419 (1), pp. 1-70 : 42

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.

Figures

FIGURE 127. Hippopodina feegeensis (Busk, 1884), RGM.1350575, Holocene, UPGG041, off South Sulawesi. Fragment with a few zooids. Scale bar: 200 µm.