SMITTINOIDEA Levinsen, 1909

Hayward, Peter J. & Winston, Judith E., 2011, Bryozoa collected by the United States Antarctic Research Program: new taxa and new records, Journal of Natural History 45 (37 - 38), pp. 2259-2338 : 2306-2308

Superfamily SMITTINOIDEA Levinsen, 1909

Family SMITTINIDAE Levinsen, 1909

Parasmittina baccula sp. nov

( Figure 22 )

Material

Holotype. NMNH 1154051 : Eltanin cruise 9, station 740, 56 ◦ 06’ to 56 ◦ 07’ S, 66 ◦ 19’ to 66 ◦ 30’ W, 494– 384 m, 18 September 1963; a single colony, in two fragments, encrusting a fragment of Reteporella .

Description

Colony encrusting, unilaminar. Autozooids large, quadrangular to irregularly hexagonal, clearly separated by raised sutures. Frontal shield lightly calcified, translucent, flat or gently convex, its surface faintly pitted; with a single series of conspicuous marginal areolar pores. Primary orifice wider than long, distal edge indistinctly crenulated, proximal edge with broad lyrula occupying about half its total width; condyles relatively large, oval, down curved, with finely denticulate edge. A single, stout spine base evident on the mid-distal edge of the orifice, its socket indicating it supported a large, basally jointed spine. Peristome well developed, tall, extending and rising proximally from each side of the distal spine; mid-proximally it has a rounded notch, above (i.e. frontal to) the lyrula paired ridges develop on the inner faces of the proximolateral lobes of the peristome, the notch therefore defining a short channel. In ovicelled zooids the peristome rim extends onto the frontal surface of the ovicell, and forms a complete tube. Avicularia present on most autozooids, proximo-lateral to the peristome, directed disto-laterally to proximo-laterally; rostrum most frequently elongate oval, 0.01 mm long, rounded and slightly broadened distally; larger avicularia with slender, parallel-sided rostra, to 0.40 mm long, with rounded tip; in both types, crossbar lacks a columella. Ovicell distinctive: as broad as long, prominent and appearing spherical, half, or less, width of autozooid; smoothly calcified, regularly perforated by small round pores, so appearing speckled and resembling a berry.

Measurements

Autozooid length: n = 15, 1.12 ± 0.21 mm (mean ± SD); autozooid width: n = 15, 0.64 ± 0.10 mm.

Etymology

Latin, baccula : a small berry, with reference to the appearance of the ovicell.

Remarks

Species of Parasmittina are found in shelf environments worldwide. The genus seems to achieve peak diversity in tropical reef habitats, and is also moderately speciose in temperate environments, but no species are known from Antarctica and only one, Parasmittina dubitata Hayward, 1980 , is presently known from the cool temperate South Atlantic. Parasmittina baccula sp. nov. resembles P. dubitata in its dimorphic avicularia, its stout lyrula and well-developed peristome, but in the latter the enlarged avicularium has a triangular, distally hooked rostrum, and there are two distal oral spines. The ovicell of P. baccula is proportionately much smaller than that of P. dubitata , and is more densely perforated, athough the autozooids of the new species may be as much as twice as long, and wide, as those of P. dubitata .

Figures

Figure 22. Parasmittina baccula sp. nov., Holotype. (A) Autozooids at a growing edge; (B) detail top show primary orifice; (C) ovicelled zooids. Scale bars: 0.5 mm (A), 0.1 mm (B), 0.25 mm (C).