Parasmittina spathulata (Smitt, 1873)

Judith L Winston, 2016, Bryozoa of Floridan Oculina reefs, Zootaxa 4071 (1), pp. 1-81 : 52

Parasmittina spathulata (Smitt, 1873)

( Fig. 28 ; Table 27 )

Escharella jacotini var. spathulata Smitt, 1873: 60 , pl. 10, figs 199, 200 (not fig. 11).

Parasmittina trispinosa var. spathulata: Osburn 1914: 208 .

Smittina trispinosa spathulata: Canu & Bassler 1928a: 114 , pl. 15, figs 9–13, text-fig. 21; 1928b: 86, pl. 6, fig. 3; Osburn 1940: 435.

Parasmittina spathulata: Cheetham & Sandberg 1964: 1037 , figs 44–47; Rucker 1967: 830, fig. 16a; Long & Rucker 1970: 20, fig. 4:5; Winston 1982: 142, fig. 70; 2005: 60, figs 161–163.

Material examined. VMNH no. 70641; USNM no. 1283253.

Description. Colony encrusting on hard substrata ( Fig. 28 A). Zooids more or less rectangular to irregularly polygonal. Frontal shield flat, imperforate, with surface made up of large hemispherical mounds of calcification ( Fig. 28 B, C), edged by row of large marginal pores. Primary orifice rounded distally, with denticulate condyles and narrow rounded lyrula ( Fig. 28 E, F). Secondary orifice teardrop-shaped at edge of low laterally, and sometimes distally, raised peristome that partly conceals primary orifice ( Fig. 28 C–D). Usually 2, sometimes 3, orificial spines, soon covered by secondary calcification. Avicularia variable in size, usually 1 long and narrow, proximally or slightly proximolaterally directed, positioned toward lateral edge of frontal wall proximal to orifice on one side and often another shorter one on the opposite side ( Fig. 28 E), each with roundly pointed rostral tip and palatal shelf occupying almost half rostral length. Larger, more-spatulate avicularia may also occur. Ovicell prominent, hyperstomial, with tops and sides covered with granular calcification, and frontal surface with many small irregularly spaced pseudopores.

Remarks. This is probably the most abundant Parasmittina occurring on subtidal to shelf-depth calcareous substrata on the southeastern U.S. coast.

Distribution. Western Atlantic: Cape Hatteras to Caribbean and Gulf of Mexico.

Figures

FIGURE 28. Parasmittina spathulata (Smitt, 1873): A, irregular encrusting colony; B, autozooids near edge of colony, showing two orificial spines; C, zooids with ooecia; D, single autozooid, showing long narrow avicularia; E, close up of orifice showing two spines and narrow lyrula; F, another orifice showing condyles and lyrula. Scale bars: A, 1 mm; B, C, 0.5 mm; D, 0.2 mm; E, F, 0.1 mm.

Tables

TABLE 27. Measurements in mm of Parasmittina spathulata (Smitt, 1873).

	Lz	Wz	Lo	Wo	Lov	Wov
N	18	18	18	18	18	18
Mean	0.556	0.361	0.104	0.100	0.214	0.240
SD	0.063	0.051	0.009	0.010	0.019	0.028
Min	0.450	0.270	0.081	0.090	0.180	0.216
Max	0.666	0.504	0.117	0.117	0.234	0.306