MICROPORIDAE Gray, 1848

Dick, Matthew H., Tilbrook, Kevin J. & Mawatari, Shunsuke F., 2006, Diversity and taxonomy of rocky-intertidal Bryozoa on the Island of Hawaii, USA, Journal of Natural History 40 (38 - 40), pp. 2197-2257 : 2211-2213

Family MICROPORIDAE Gray, 1848

Genus Micropora Gray, 1848 Micropora rimulata Canu and Bassler, 1929

( Figure 5D )

Micropora rimulata Canu and Bassler 1929, p 137 , Plate 14, Figure 4 .

? Micropora coriacea: Canu and Bassler 1927, p 7 , Plate 1, Figure 6 .

Measurements

ZL, 0.53–0.75 (0.663¡0.069), not including distal avicularium. ZW, 0.40–0.54 (0.479¡0.043). AzOrL, 0.08–0.10 (0.090¡0.008). AzOrW, 0.14–0.18 (0.156¡0.014). OvZOrL, 0.10–0.11 (0.105¡0.006). OvZOrW, 0.16–0.19 (0.169¡0.010). OvL, 0.25– 0.33 (0.290¡0.025). OvW, 0.25–0.30 (0.280¡0.017).

Description

Colony unilaminar, encrusting, sheet-like, white in colour, with glistening ectocyst. Zooids variable in shape; irregularly rounded-hexagonal, barrel-shaped, or tapering pyriform in outline; sometimes as broad as long; distinct, delineated by a thin incision and a thickened, raised, granulated margin most pronounced where it borders the opesiules. Frontal wall flat to slightly convex, finely granulated, evenly perforated with fine pores, with a large, elongate opesiule, often tapering proximally, on each side proximolateral to orifice. Orifice elevated from frontal surface by a raised, granulated proximal border confluent with raised zooidal margins lateral to opesiules; flanked by a smooth knob on each side. Orifice dimorphic; almost quadrate with rounded distolateral corners in non-ovicellate zooids; broader than long, semicircular, and larger in ovicellate zooids. Ovicell distinct, about as broad as long, partly sunken in frontal wall of distal zooid, imperforate, finely granulated with same texture as frontal wall, the proximal margin with a smooth, raised, chevronshaped lip usually with a tubercle at the apex; closed by operculum. An avicularium lies distal to orifice of non-ovicellate zooids; chamber raised, smooth, almost semicircular in outline, the rostrum occupying most of the top; hinge bar complete; mandible acute, longer than broad, in the shape of a right triangle, distal edge slightly longer than the proximal, pointing laterally or slightly proximolaterally. Spines lacking.

Remarks

We identify our material as M. rimulata on the basis of similar zooidal measurements; the imperforate ovicell narrower than zooid width; the chevron-shaped ridge, with an apical median boss, forming the proximal margin of the ovicell (in the original description by Canu and Basler 1929, the boss is slightly separate from the ridge as a central tubercle on the ovicell); the dimorphism in orifice size between ovicellate and non-ovicellate zooids (not as pronounced in our material as in the original description); and particularly the shape and orientation of the avicularian mandible. Canu and Bassler (1927) reported nominal M. coriacea ( Johnston, 1847) , a European species (see Harmer 1926 for a discussion of this species’ nomenclatural problems), from 335–483 m depth off Oahu; the specimen they illustrated is similar in many respects to our material and may be conspecific. Soule et al. (1988) reported two Micropora species of uncertain identity from the Hawaiian Islands.

Distribution

The only other report of M. rimulata is from the Philippines ( Canu and Bassler 1929).

Figures

Figure 4. Corbulella extenuata n. sp., holotype (NHM 2006.7.21.5): (A) autozooid, unbleached; (B) marginal zooids, bleached; note cap-like reduced ovicells; (C) autozooids and interzooidal avicularium (centre), bleached; (D) lateral wall of marginal autozooid showing septula, bleached. (B–D) are from same colony as (A), after bleaching. Scale bars: 500 Mm (A, C, D); 400 Mm (B).

Figure 5. (A, B) Antropora minor (Hincks): (A) autozooids, bleached; (B) autozooids, bleached; zooid at right is a brooding zooid, with a raised, smooth distal margin that may represent a vestigial ovicell. (C) Beania discodermiae (Ortmann): autozooids, unbleached. (D) Micropora rimulata Canu and Bassler: autozooids and ovicellate zooids, bleached. Scale bars: 200 Mm (A, B); 500 Mm (C, D).

Figure 6. (A, C, E, G) Puellina harmeri Ristedt: (A) autozooid, ovicellate zooids, and avicularia; (C) ancestrula and periancestrular zooids; (E) marginal zooids, showing long distal spines and marginal avicularium; (G) oblique view of autozooids and ovicellate zooids. (B, D, F, H) Puellina septemcryptica n. sp.: (B) paratype (NHM 2006.7.21.7),