Celleporella Gray, 1848

Dick, Matthew H., Grischenko, Andrei V. & Mawatari, Shunsuke F., 2005, Intertidal Bryozoa (Cheilostomata) of Ketchikan, Alaska, Journal of Natural History 39 (43), pp. 3687-3784 : 3724-3726

Genus Celleporella Gray, 1848

Celleporella hyalina ( Linnaeus, 1767) species complex

( Figure 9A–D )

Description

Colony. White, hyaline, vitreous; coherent; unilaminar when young; multilaminar with age, often several layers thick. At Ketchikan, we collected colonies growing intertidally on rocks, as well as subtidally on mussel shells; largest colony observed 1.5 cm across. Primary layer with autozooids only; male, ovicellate, and autozooids frontally budded in secondary layers.

Zooids. Young, marginal zooids spindle-shaped, 0.48–0.63 mm long (average 50.542 mm, n 515, 3) by 0.23–0.28 mm wide (average 50.248 mm, n 515, 3), separated by a deep groove, with slit-like lacunae evident between them; autozooids distinct only in young colonies and in marginal budding zone, the distal ends overlapping the proximal ends of subsequent zooids. One or two tiny incipient zooids often arise from pore chambers along either lateral margin. Ovicellate zooids much shorter than autozooids, triangular in shape, generally obscured by surrounding zooids. Male zooids shorter than autozooids but of similar form, often obscured for much of their length by surrounding zooids. Basal wall of autozooids in primary layer either completely calcified, or with an elongate uncalcified area in centre.

Frontal wall. Quite convex, thin, vitreous, translucent, imperforate, with or without irregularly spaced transverse striations or weak ridges; sometimes with a thickening of proximal orificial margin forming a low, transverse umbo.

Orifice. Autozooidal orifice ( Figure 9A, C ), including proximal sinus, roughly circular or longer than broad, 0.13–0.16 mm long (average 50.140 mm, n 515, 3) by 0.11–0.14 mm wide (average 50.124 mm, n 515, 3), with conspicuous, shelf-like condyles at proximolateral margins delineating a deep, broad, U-shaped proximal sinus that is variably flattened at the bottom. Male orifice ( Figure 9B, D ) similar in shape, roughly onehalf to two-thirds the length and width of the autozooidal orifice. Female secondary orifice, including proximal margin of ovicell, semicircular in frontal view and with a concave proximal margin in distal view.

Spines. Lacking.

Avicularia. Lacking.

Ovicell ( Figure 9B, D ). Occurring densely in central, frontally budded, fertile zone of colony; thin-walled, prominent, globose, irregular in shape, orientation, and size, 0.18–0.23 mm long (average 50.195 mm, n 515, 3) by 0.18–0.26 mm wide (average 50.214 mm, n 515, 3); with 12–18 conspicuous pores (average515, n 510, 1) distributed over entire surface.

Ancestrula . Like a small autozooid in form; budding pattern a spiral, with first bud arising distolaterally from ancestrula and each subsequent bud arising from angle between ancestrula and preceding bud.

Remarks

In addition to colonies collected intertidally, we examined several specimens encrusting a mussel ( Mytilus edulis ) shell growing subtidally in a boat harbour near the East Tongass Narrows site. The intertidal distribution of this species was not adequately determined due to difficulty in distinguishing it in the field from multilaminar colonies of C. reflexa . Our impression is that C. hyalina sensu lato was much less common on intertidal rocks than C. reflexa .

Celleporella hyalina ( Linnaeus, 1767) has historically been treated as a widely distributed species. For example, Osburn (1952) noted, ‘‘It is a truly cosmopolitan species, occurring around the world and from the Arctic … to the tropics. It has been reported by everyone who has studied Pacific coast Bryozoa, from Alaska to southern California …’’ Recently, however, morphological, molecular genetic, and mating-compatibility studies (e.g. Hoare et al. 2001; Hughes et al. 2003; Navarette et al. 2003, 2005) have shown that C. hyalina (L.) is likely only part of a complex of sibling or cryptic species, with at least 11 major, genetically divergent lineages worldwide. Morris (1980: Text-figure 14) illustrated variation in orifice shapes for nominal C. hyalina along the Pacific coast of North America, which might reflect inter-lineage or even interspecific variation.

The specimens from Ketchikan are undoubtedly synonymous with some of the previous records of nominal C. hyalina from the north-eastern Pacific. For instance, one of the orifice shapes shown by Morris (1980: Text-figure 14, left) for Alaskan material is similar to that of one of our specimens ( Figure 9C ); however, this colony ( Figure 9C, D ) had a distinctly larger orifice (0.15–0.20 mm long, average 50.178 mm, n 510, 1; 0.13–0.16 mm wide, average 50.147 mm, n 510, 1) than others examined. It is questionable whether any of our specimens are conspecific with C. hyalina (L.); measurements of the autozooid and autozooidal orifice are considerably larger than those reported for British material by Morris (1980) and Hayward and Ryland (1999).

Until the taxonomy of the C. hyalina species complex is better understood through integrated morphological, molecular, and reproductive-compatibility studies, we simply refer specimens from Ketchikan to this species complex. For the same reason, we include neither synonymies nor distributional data.

Figures

Figure 9. Celleporella hyalina (L.) species complex, showing variation between two colonies encrusting a single mussel (Mytilus edulis) individual collected subtidally; (A, B) are from one colony, (C, D) are from the other; both specimens bleached. (A) Autozooids near colony margin; (B) autozooids in primary layer (large primary orifices), a frontally budded male zooid (small primary orifice, at left), and frontally budded ovicellate zooids; (C) autozooids near colony margin; (D) autozooids in primary layer (large primary orifices), frontally budded male zooids (small primary orifices), and frontally budded ovicellate zooids. Scale bars: 500 Mm.