Alderina flaventa, 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 : 2204-2206

Order CHEILOSTOMATIDA Busk, 1852

Suborder NEOCHEILOSTOMINA d’Hondt, 1985 Infraorder FLUSTRINA Smitt, 1868 Superfamily CALLOPOROIDEA Norman, 1903 Family CALLOPORIDAE Norman, 1903 Genus Alderina Norman, 1903 Alderina flaventa new species

( Figure 3A–C )

? Alderina smitti Osburn 1950, p 59 (in part?).

Type material

Holotype: NHM 2006.7.21.1, specimen HI-50, 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 2006.7.21.2, specimen HI-42, bleached, coated for SEM. Paratype 2, NHM 2006.7.21.3, unbleached specimen. Paratype 3, NHM 2006.7.21.4, unbleached specimen; with Parellisina albida and Hippopodina iririkiensis . Paratype 4, YPM-38550, unbleached specimen; with Junerossia copiosa . Paratype 5, YPM-38551, unbleached specimen.

Etymology

The species name derives from the Latin flavens (yellow or gold coloured), referring to the conspicuous frontal pigmentation.

Measurements

ZL, 0.63–0.75 (0.656¡0.038). ZW, 0.39–0.48 (0.438¡0.032). OpL, 0.30–0.54 (0.451¡0.060). OpW, 0.26–0.33 (0.295¡0.021). OvL, 0.20–0.23 (0.208¡0.011). OvW, 0.38–0.45 (0.395¡0.033) (ovicells n 55).

Description

Colony unilaminar, encrusting, sheet-like, tan in colour; living zooids with white walls and with patchily distributed, golden-yellow granular pigmentation visible under transparent frontal membrane; margin of operculum with a reddish brown bordering sclerite. Zooids ( Figure 3A, B ) moderately large; oval or barrel-shaped in outline; distinct, separated by a shallow groove; basal wall completely calcified. Gymnocyst narrow, smooth, sloping basally, typically surrounding the zooid. Mural rim raised, sharp, finely crenulate on top. Cryptocyst narrow, sloping, tapering distally; coarsely crenulate, with beaded ribs perpendicular to circumference. Opesia ( Figure 3A, B ) broadly oval, elliptical, or bluntly triangular, the outline scalloped due to the cryptocystal ribbing. Spines and avicularia lacking. Ovicell ( Figure 3A–C ) raised, smooth, broader than long, closed by operculum; often with a narrow transverse slit or small irregular pore on top due to incomplete closure of ectocyst; tabula lacking. Zooids interconnect ( Figure 3C ) by a single uniporous septulum in the distal wall and one or two in each distolateral wall.

Remarks

Osburn (1950) reported two species of Alderina from the Pacific coast of North America, A. brevispina ( O’Donoghue and O’Donoghue, 1926) and A. smitti Osburn, 1950 . The former has larger zooids than our material, sometimes a minute spine or nodule lateral to the orifice, and a prominent transverse ridge across the ovicell. Alderina smitti , originally described from Florida as Membranipora irregularis Smitt, 1873 (a name preoccupied by Membranipora irregularis d’Orbigny ), has been considered to be broadly distributed in the subtropical to tropical western Atlantic and eastern Pacific ( Osburn 1950). However, it is unlikely that all the reports of this nominal species represent a single species, since descriptions indicated in Osburn’s (1950) synonymy show considerable variation. Hastings (1930), for example, indicated a coarsely granulated ovicell in material from the tropical eastern Pacific. Both the original ( Smitt 1873) and Osburn’s (1950) subsequent descriptions show the opesia broadest proximally, and Osburn indicates smaller zooids than ours for material from the eastern Pacific. There are few records of the genus from the Indo-West Pacific; a report of A. imbellis ( Hincks, 1860) , a northern Atlantic species, from the Philippines ( Canu and Bassler 1929) is almost certainly erroneous. Gordon (1986) described Alderina pacifera (as Antropora pacifera ) from New Zealand (see Tilbrook 1998).

Distribution

This is the first record of an Alderina from the Hawaiian Islands . The species is known only from Kapa’a on the Island of Hawaii .

Figures

Figure 3. (A–C) Alderina flaventa n. sp., holotype (NHM 2006.7.21.1): (A) group of autozooids and ovicellate zooids; (B) ovicellate zooid; (C) colony margin showing uniporous septula. (D) Parellisina albida (Hincks): autozooids, ovicellate zooid, and interzooidal avicularia. All specimens bleached. Scale bars: 500 Mm (A, C, D); 400 Mm (B).