Microporella ordo Brown, 1952

Martino, Emanuela Di, Taylor, Paul D. & Gordon, Dennis P., 2020, Erect bifoliate species of Microporella (Bryozoa, Cheilostomata), fossil and modern, European Journal of Taxonomy 678, pp. 1-31 : 14-15

Microporella ordo Brown, 1952

Fig. 7 ; Table 5

Microporella ordo Brown, 1952: 257 , figs 189–193.

Microporella ordo – Powell 1967: 291, text-fig. 54.

Material examined

Holotype

NEW ZEALAND • Wanganui, Castlecliff; NZGS Loc. 4013; late Pleistocene; Castlecliffian Horizon CU3 (ca 0.55 myr); NHMUK D36809 (figured in Di Martino et al. 2017: fig. 5).

Additional material (figured)

NEW ZEALAND • Fragment from large colony, bleached; Spirits Bay ; Recent; NIWA 144880 ( Fig. 7 A– C) • Fractured section; Recent; NIWA 144881 ( Fig. 7D ) • Fragment 2, unbleached; Spirits Bay ; Recent; NIWA 144882 ( Fig. 7 E–F).

Additional material (not figured)

NEW ZEALAND • 1 specimen; [33.9655° S, 171.7723° E]; depth 92–96 m; St. TAN1105/42; Recent; NIWA 73196 • 2 specimens; [37.5947° S, 178.8660° E]; depth 56–58 m; St. TAN1108/239 ; Recent; NIWA 75495 , 75499 • 1 specimen; [34.3780° S, 172.7100° E]; depth 48 m; St. KAH9901/45 ; Recent; NIWA 99099 • 1 specimen; [34.3782° S, 173.0265° E]; depth 64–65 m; St. TAN0906/170 ; Recent; NIWA 56945 • 1 specimen; [34.3813° S, 172.6618° E]; depth 54 m; St. KAH9901/69 ; Recent; NIWA 99072 • 1 specimen; [34.3690° S, 172.8250° E]; depth 55 m; St. KAH9901/25 ; Recent; NIWA 114233 • 1 specimen; [34.3600° S, 172.6968° E]; depth 46 m; St. KAH9901/31 ; Recent; NIWA 128424 .

Description

COLONY. Erect, bifoliate, the largest about 110 × 75 mm, with broad branches fused at edges to form a boxwork colony; interzooidal communication Via multiporous septula, elliptical, 55 µm long by 45 µm wide, with at least 12 circular pores ca 4 µm in diameter, placed in the basal lateral walls on distolateral corners of autozooids.

AUTOZOOIDS. Distinct with interzooidal boundaries marked by narrow grooves, rounded rectangular to hexagonal, longer than wide (mean L/W = 1.63). Frontal shield flat to Very slightly conVex, pustulose, the pustules about 20–30 µm in diameter; marginal areolae numbering about 10, elongate near growing edge (25–45 µm long by 15–20 µm wide), becoming indistinguishable from frontal pores in older zooids; non-marginal pseudopores moderately large (diameter 8–18 µm), numbering about 20–30, arranged semi-regularly.

ORIfICE. Semielliptical, significantly wider than long, hingeline straight to weakly concaVe, with about 15 teeth, equal in size except for slightly longer outer one or two pairs; oral spines lacking; folded back transverse vertical wall of distal zooid forming a slightly elevated crescent secondary rim above the distal margin of the primary orifice; operculum smooth.

ASCOPORE fIELD.As a raised area of gymnocystal calcification at approximately same leVel as orifice but beneath leVel of adjacent frontal shield, located moderately close to orifice hingeline, about 60–70 µm below, separated from it by non-porous pustulose cryptocyst; reniform to transVersely elliptical, 45 × 60 µm, opening heart-shaped, 25 × 40 µm, coVered by filigree sieVe plate, a narrow, bifurcated tongue usually projecting from the distal edge.

AVICULARIUM. Single, moderately large, present in the majority of autozooids, positioned level with or slightly distally of and almost abutting the ascopore, oriented distolaterally to almost laterally; crossbar complete; opesia semielliptical; rostrum short, teat-shaped, the distal end rounded, distinct channel present. Mandible in dried material with short (ca 90–110 µm) pointed seta, narrow throughout, hooked on underside, lying across or a little proximal of ascopore when open.

OVICELLS. Very large, often covering frontal shield of distal zooid as far as ascopore, bulbous, subcircular or a little longer than wide, non-personate; calcification similar to frontal shield but with finer pustules, continuous with frontal shield of distal zooid; small pseudopores distributed across entire surface, more closely spaced compared to those on the frontal shield, radially aligned near margins; orifice of oVicellate zooids hidden in frontal view.

Remarks

The description given above and measurements in Table 5 are based on Recent examples of this species which show the morphology of the species better than the type and other fossil material. Although very similar to Microporella hyadesi in its general appearance, M. ordo is easily distinguished by its heartshaped ascopore with filigree sieVe plate and narrow bifurcated tongue, in addition to the non-personate ovicells.

The present-day range of the species extends from NW of the Three Kings Islands at Middlesex Bank to Ranfurly Banks off East Cape, New Zealand (33.9– 37.6° S; depth 46–96 m).

Figures

Fig. 7. Microporella ordo Brown, 1952, Recent, Spirits Bay, New Zealand. A–C. NIWA 144880. A. General view of a branch fragment. B. Group of ovicellate and non-ovicellate zooids. C. Close-up of two autozooids, that on the right with preserVed filigree sieVe plate. D. NIWA 144881, transversal view of the bifoliate branch showing multiporous septula. E–F. NIWA 144882. E. Group of unbleached autozooids showing opercula and thin, pointed avicularian mandibles. F. Close-up of the ascopore and the aVicularian mandible. Scale bars: A = 1 mm; B, D–E = 200 µm; C = 100 µm; F = 50 µm.