Alderina smitti Osburn, 1950

Winston, Judith E. & Vieira, Leandro M., 2013, Systematics of interstitial encrusting bryozoans from southeastern Brazil, Zootaxa 3710 (2), pp. 101-146 : 106-107

Alderina smitti Osburn, 1950

( Fig. 4 ; Table 2 )

Membranipora irregularis Smitt, 1873: 8 , pl. 2, fig. 63; Osburn 1914: 194. (Homonym of Membranipora irregularis d’Orbigny, 1839: 17).

Alderina irregularis: Canu & Bassler 1928a: 27 , pl. 3, fig. 3, pl. 32, fig. 4; Hastings 1930: 708, pl. 3, figs 11–12; Osburn 1940: 363; Marcus 1941: 15, pl. 1, fig. 2.

Alderina smitti Osburn, 1950: 59 , pl. 6, fig. 2; Winston & Håkansson 1986: 11, figs 17–18.

Material examined. MZUSP 706 ( Fig. 4 ) measured specimen #1 on SEM stub, BIOTA Stn 205; VMNH 70002, measured specimen #2, BIOTA Stn 205.

Description. Colony encrusting. Zooids oval in shape, the oval frontal membrane underlain by a depressed cryptocyst with aligned beads of calcification. Orifice marked on distal wall skeleton by indentations. Gymnocyst smooth and narrow, but with several projecting tubercles. Large lateral pore chambers are visible at growing edge. No avicularia. Ooecia broad, thickened crescents of calcification.

Remarks. Alderina smitti was first reported from Brazil under the name Alderina irregularis (Smitt, 1873) on shells in Paraná state, southern Brazil (Marcus 1941). This species was rare in our samples, but is one of the few species that appear in both Floridan and Brazilian sand faunas, although zooids from Brazilian populations are about 25% larger than those from Florida. Osburn’s original description of the species (Osburn 1950, p. 60) recorded it as occurring in Florida, the Caribbean and Gulf of Mexico as well as from southern California on the Pacific coast. It can become reproductively mature after producing only 3–4 zooids from the site of larval metamorphosis.

Distribution. Tropical western Atlantic, Gulf of Mexico, and Eastern Pacific.

Figures

FIGURE 4. Alderina smitti Osburn, 1950: A, portion of a colony that has grown between two spirorbin tubes. B, close-up of an ovicelled zooid and parts of adjacent zooids, showing granular cryptocyst. Scale bars: A, B, 0.2 mm.

Tables

TABLE 2. Measurements (in mm) of Alderina smitti Osburn, 1950.

	Lz	Wz	Lop	Wop	Lo	Wo
N	12	12	12	12	9	10
Mean	0.341	0.266	0.196	0.164	0.051	0.080
SD	0.060	0.024	0.025	0.030	0.006	0.018
Min	0.270	0.216	0.162	0.108	0.036	0.054
Max	0.450	0.288	0.252	0.216	0.054	0.108