Calyptotheca kapaaensis, 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 : 2231-2232

Genus Calyptotheca Harmer, 1957

Calyptotheca kapaaensis new species

( Figure 11D, E )

Type material

Holotype: NHM 2006.7.21.15, specimen HI-37, bleached, coated for SEM; Kapa’a Beach Park, Island of Hawaii; 1 March 2005; M. H. Dick, collector; intertidal, 0.15 m low tide . Paratype: NHM 2006.7.21.16, same locality and collecting information as for holotype; unbleached specimen.

Etymology

The species name is derived from the type locality, Kapa’a.

Measurements ZL, 0.45–0.83 (0.580¡0.122). ZW, 0.26–0.48 (0.383¡0.058). OrL, 0.08–0.10

(0.086¡0.008). OrW, 0.11–0.14 (0.125¡0.009).

Description

Colony unilaminar, encrusting, tan-white in colour. Zooids moderately inflated, separated by a groove and often a raised suture line. Frontal wall ( Figure 11D ) well calcified, rugose, covered with small, circular pores that are densest in central area, fewer or lacking close to the lateral and proximal margins, where there can be a few larger marginal pores. Orifice ( Figure 11E ) markedly broader than long, anter broadly semicircular, separated from poster by a rounded shelf on each side; in the inside curvature of each shelf is a prominent semicircular condyle that is serrated on the edge; poster is a broad sinus extending between the condyles. Medial suboral avicularium ( Figure 11D, E ) tiny, separated from orifice by less than twice the width of the avicularium; rostrum nearly circular, tilted at an acute angle, with a tiny, semicircular mandible directed proximally; no other frontal avicularia observed. Oral spines lacking. No ovicells present in our specimens.

Remarks

Our specimens resemble several other Calyptotheca species with a small, median suboral avicularium and large, serrated condyles, including C. inclusa ( Thornely, 1906) , C. incompta ( Hayward, 1988) , and C. reniformis Tilbrook, 2006 ( Winston and Heimberg 1986; Hayward 1988; Tilbrook 2006). However, the orifice of C. inclusa is about as broad as long, with a narrower sinus, and the suboral avicularium is proportionately larger than in C. kapaaensis . In C. incompta , the suboral avicularium is small and oval, and the orifice is markedly broader than long, as in C. kapaaensis . However, the pores of C. incompta are slitlike rather than circular; zooids can have an additional, larger frontal avicularium near the proximal margin, which was not seen in our specimens; and the sinus is narrower and tapering. In C. reniformis , the frontal pores are reniform and the orifice is pear-shaped. Measurements of both C. inclusa and C. incompta given in the literature indicate smaller zooids than for our specimens. We place this species into Calyptotheca based on the diagnosis of that genus by Tilbrook (2006); the shelf-like platform on the edge of the distal orificial rim is scarcely developed, but is evident in SEM images.

Distribution

Kapa’a Shore, Island of Hawaii, is the only known locality.

Figures

Figure 11. (A) Hippopodina iririkiensis Tilbrook: autozooids and ovicellate zooids. (B, C) Cosciniopsis lonchaea (Busk): (B) autozooids and ovicellate zooids; (C) enlargement showing shapes of primary and secondary orifices. (D, E) Calyptotheca kapaaensis n. sp., holotype (NHM 2006.7.21.15): (D) autozooids; (E) enlargement of primary orifice and suboral avicularium. (F) Cheiloporina haddoni Harmer: autozooids and one ovicellate zooid (upper left). All specimens bleached. Scale bars: 1 mm (A, B, F); 200 Mm (C); 500 Mm (D); 100 Mm (E).