Stylopoma varus Tilbrook, 2001

Martino, Emanuela Di & Taylor, Paul D., 2018, Early Pleistocene and Holocene bryozoans from Indonesia, Zootaxa 4419 (1), pp. 1-70 : 31

Stylopoma varus Tilbrook, 2001

( Figs 86–88 ; Table 19)

Stylopoma varus Tilbrook, 2001: 27 , fig. 11A–C; Tilbrook, 2006: 192, pl. 40, figs E, F.

Figured material. RGM.1350565, Holocene, UPGG 041, off South Sulawesi.

Description. Colony encrusting, multiserial, multilaminar. Autozooids with distinct interzooidal furrows, irregularly arranged, polygonal, slightly longer than broad (mean L/W = 1.12). Frontal shield convex, granular, densely perforated; pseudopores circular, each set in a polygonal depression; marginal areolar pores larger and distinct; a central umbo visible in some zooids. Primary orifice wider than long (excluding sinus), transversely Dshaped, anter smooth, proximal edge straight with a narrow, U-shaped, median sinus; condyles denticulate, rectangular, occupying the majority of the proximal border on each side of the sinus. A single, small, adventitious avicularium located proximolateral of the orifice and distolateral directed; rostrum triangular, raised; crossbar complete. Sometimes additional, adventitious, oval avicularia, similar in size to those lateral to the orifice, are placed elsewhere on the frontal shield, randomly directed. Vicarious avicularia and complete ovicells not observed.

Remarks. A single colony of Stylopoma varus was found in our samples. This species was originally described from the South China Sea at about 50 m depth, and the Torres Strait (Tilbrook 2001), and subsequently found in the Solomon Islands ( Tilbrook 2006). Stylopoma varus is characterized by the presence of a central umbo on the frontal shield, and an abundance of frontal adventitious avicularia. However, in the small fragment available for study, the central umbo is unequivocally visible only in some of the zooids.

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

Figures

FIGURES 86–88. Stylopoma cf. varus Tilbrook, 2001, RGM.1350565, Holocene, UPGG041, off South Sulawesi. 86. View of the colony fragment. 87. Close-up of two autozooids, adventitious avicularia and a broken ovicell. 88. Close-up of an orifice. Scale bars: Fig. 86 = 200 µm; Fig. 87 = 100 µm; Fig. 88 = 50 µm.