Favosipora adunca, Dick & Tilbrook & Mawatari, 2006

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 : 2247-2249

Favosipora adunca new species

( Figure 17A–F )

Type material

Holotype: NHM 2006.7.21.24, specimen HI-58b, bleached, coated for SEM; Kapa’a Beach Park, Island of Hawaii; 1 March 2005; M. H. Dick, collector; intertidal, 0.15 m low tide . Paratypes: same locality and collecting information as for holotype. Paratype 1, NHM 2006.7.21.25, specimen HI-1, bleached, coated for SEM. Paratype 2, NHM 2006.7.21.26, specimen HI-3 (part), bleached, coated for SEM. Paratype 3, NHM 2006.7.21.27, specimen HI-72, bleached, coated for SEM. Paratype 4, YPM-38559, specimen HI-54, bleached, coated for SEM. Paratype 5, YPM-38560, specimen HI-77, bleached, coated for SEM. Paratype 6, YPM-38561, bleached specimen, uncoated.

Etymology

The species name derives from the Latin aduncus (bent in, crooked), referring to the bent oeciostome.

Measurements

Peristome opening near margin slightly elliptical, 0.09–0.13 long (0.108¡0.011)×0.08– 0.11 wide (0.089¡0.011); maximum dimension of kenozooidal opening 0.05–0.14

(0.092¡0.022) (n 515; five measurements from each of three colonies). Brood chamber 1.20–1.38 long×0.68–0.80 wide (n 53).

Description

Colony small, smallest observed 5 mm × 3 mm, largest observed 8 mm × 7 mm; discoid, raised in centre, whitish in colour; roughly circular or arranged along a long axis; with a broad marginal lamina striated with fine ridges orientated perpendicular to margin, indicating incipient zooids; colony adnate over most of centre, but lamina is variably raised from the substratum, sometimes sharply. Central macular area ( Figure 17A ) of colony tends to be elongate, even in nearly circular colonies; rarely there are two macular centres. Zooidal peristomes ( Figure 17A, B ) sometimes single or connate in groups of two to four, but usually are in connate radial series of up to 12 zooids, generally uniserial but occasionally partly biserial. Peristomes in a connate row are tall near centre of colony and become progressively shorter toward the margin. Peristomes tapered; bicuspid ( Figure 17B ), with a blunt-triangular cusp on the admacular and another on the abmacular side; occasionally occluded by a centripetally growing closure plate. Openings of kenozooids can also become constricted or closed by centripetal growth of a horizontal lamina. Calcification of colony surface and interior of peristomes and kenozooids ( Figure 17F ) smooth, without granulation, mural spines, or pinhead spinules. Brood chamber ( Figure 17C–E ) elongate, irregular, extending as one or two lobes between two or three adjacent columns of connate peristomes, respectively. The largest colony had three brood chambers, one situated at the edge of the central macular area and the others halfway between the macular area and the margin. Floor of brood chamber ( Figure 17E ) thinly covering kenozooidal openings, sparsely granulated, with three to six small, circular pores leading to each kenozooid; roof of brood chamber begins to form by centripetally growing struts of calcification. When complete, roof is more-or-less flat, slightly depressed, densely perforated by pseudopores ( Figure 17D ), sharply delineated from smooth, sloping circumferential wall. Oeciostome ( Figure 17D ) lies at margin of brood chamber, raised, bent at a right angle so that plane of transversely oval opening is perpendicular to roof.

Remarks

The combined characters of smooth mural surfaces; peristomes bicuspid and typically in long, connate, mostly uniserial series of up to 12; the macular area usually elongate; and the bent oeciostome separate this from other species of Favosipora .

Distribution

The genus Favosipora is primarily distributed in the Southern Hemisphere; according to Gordon and Taylor (2001), only one other species of this genus, F. holdsworthii ( Busk, 1875) , has been recorded from the Northern Hemisphere. Kapa’a beach, Hawaii Island, is the only known locality.

Figures

Figure 17. Favosipora adunca n. sp.: (A) paratype 1 (NHM 2006.7.21.25), partial view of colony; (B) paratype 1, enlargement of fused peristomes of autozooids; (C) holotype (NHM 2006.7.21.24), brood chamber; (D) holotype, enlargement of brood chamber, showing oeciostome (top, right of centre); (E) paratype 4 (YPM-38559), detail of brood-chamber formation, showing granulated floor and struts of calcification that will contribute to covering; (F) paratype 4, enlargement of kenozooidal openings. All specimens bleached. Scale bars: 1 mm (A); 200 Mm (B, D, E); 500 Mm (C); 100 Mm (F).