Rectimicropora conspicua, Hayward & Winston, 2011

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 : 2268-2270

Rectimicropora conspicua sp. nov.

( Figure 5 )

Material

Holotype. NMNH 1154046 : Eltanin cruise 27, station 1852, 49 ◦ 40’ to 49 ◦ 38’ S, 178 ◦ 56’ to 178 ◦ 57’ E, 952–1336 m, 3 January 1967; one colony in about 10 fragments.

Paratype. NMNH 1154046 : Eltanin cruise 27, station 1851, 49 ◦ 40’ S, 178 ◦ 53’ to 178 ◦ 54’ E, 476–540 m, 3 January 1967; one fragment .

Description

Colony slender, delicate; branches c. 0.5 mm wide, with maximum 5 mm between dichotomies. Autozooids in alternating back-to-back pairs, elongate, angular with distal end projecting from frontal plane, each bordered by thin, raised edge, length four times width. Cryptocystal frontal shield flat or slightly concave, finely granular, with sparse, inconspicuous perforations; small opesiules present close to lateral walls in distal half of autozooid. Opesia with straight proximal edge twice as wide as long, occupying distal one-sixth of autozooid frontal length. An adventitious avicularium immediately distal to opesia, with small, round cystid and pointed rostrum, acute to frontal plane and directed disto-laterally. Ovicell elongate, prominent, ovoid, occupying half frontal length of autozooid distal to maternal zooid, densely calcified; the maternal zooid appears to be dimorphic, with a larger, more thickly rimmed opesia, the distal rim of which forms the overhanging aperture of the ovicell, and from which a median longitudinal ridge extends for much of the length of the ovicell.

Dichotomies appear to be simple fracture joints, discontinuities in the calcification, with light brown chitinous thickening.

Measurements

All for n = 10 individuals, mean ± SD: autozooid length 0.94 ± 0.15 mm; autozooid width 0.26 ± 0.04 mm; opesia length 0.08 ± 0.01 mm; and opesia width 0.15 ± 0.008 mm.

Etymology

Latin, conspicuus: manifest, with reference to the distinctive morphology.

Remarks

The material is limited, but sufficient to demonstrate the distinctive morphological features that define the species.

Figures

Figure 5. Rectimicropora conspicua sp. nov., Holotype. Portion of colony with avicularia and an ovicelled zooid. Scale bar: 0.25 mm.