Mucropetraliella loculifera Harmer, 1957

Martino, Emanuela Di & Taylor, Paul D., 2018, Early Pleistocene and Holocene bryozoans from Indonesia, Zootaxa 4419 (1), pp. 1-70 : 44-45

Mucropetraliella loculifera Harmer, 1957

( Figs 130–132 ; Table 29)

Mucropetraliella loculifera Harmer, 1957: 90 , pl. 46, figs 3–7; Tilbrook & Cook, 2004: 321, fig. 1E, F.

Figured material. RGM.1350578, Holocene, UPGG 041, off South Sulawesi.

Description. Colony encrusting, multiserial, unilaminar. Autozooids distinct with shallow interzooidal furrows, large, polygonal, longer than wide (mean L/W = 1.30). Frontal shield convex, evenly perforated with large pseudopores set in polygonal depressions. Orifice seemingly bell-shaped with occlusor-laminae and median denticle; lateral denticles and condyles not observed; a pointed suboral mucro present. Two small oral spine bases visible in one of the zooids. Adventitious avicularia of different sizes and shapes present, small and oval (95 µm long by 75 µm wide) to large and teardrop-shaped (195 µm long by 125 µm wide), placed either below or lateral to the orifice, or elsewhere on the frontal shield. Ooecium not observed.

Remarks. Although poorly preserved, this single fragment can be confidently assigned to Mucropetraliella loculifera based on the diagnostic presence of occlusor-laminae within the orifice ( Harmer 1957; Tilbrook & Cook 2004). Additional characters, such as the pseudoporous frontal shield, the presence of the suboral umbo and avicularium, additional adventitious avicularia and oral spine bases, support this identification. Mucropetraliella loculifera is known from several stations off Indonesia, Singapore and Sri Lanka ( Harmer 1957).

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

Figures

FIGURES 130–132. Mucropetraliella loculifera Harmer, 1957, RGM.1350578, Holocene, UPGG041, off South Sulawesi. 130. View of the colony fragment. 131. Group of zooids with various adventitious avicularia; note the pointed suboral mucro in the central placed zooid with the zooid immediately below having two small, oral spine bases and a median denticle within the orifice, as well as an occlusor-lamina on the right-hand side of the orifice; occlusor-laminae are visible also on the zooids placed on the right-hand side of the image. 132. Close-up of an occlusor-lamina. Scale bars: Fig. 130 = 500 µm; Fig. 131 = 200 µm; Fig. 132 = 100 µm.