Puellina caesia, Dick & Grischenko & Mawatari, 2005

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 : 3722-3724

Puellina caesia , new species

( Figure 8A–D )

Puellina setosa: Osburn 1950, p 186 , Plate 29, Figure 4 (in part?).

Diagnosis

Lateral and proximal gymnocyst evident, sometimes extensive; frontal shield nearly circular, composed of 10–14 costae; one papilla pore and usually one intercostal pore between adjacent costae; intercostal pores arranged in a circle in centre of frontal shield, inside circle of papilla pores; with a pair of long setiform papillae near orifice; non-ovicellate zooids usually with four (range three to five) orificial spines; ovicell imperforate, smooth, often umbonate or keeled, the ectooecium confluent with frontal wall of next distal zooid; avicularia lacking.

Type material

Holotype: ETN, specimen KE-20 bleached and coated for SEM ( YPM 35850) . Paratype: ETN, specimen KE-64 unbleached and coated for SEM ( YPM 35851) .

Etymology

The species name comes from the Latin caesia , meaning bluish grey, referring to the colour of the colony when alive.

Description

Colony. Unilaminar, sheet-like, encrusting hard substrates, bluish grey when alive, roughly circular; largest observed 3 cm in diameter.

Zooids. Rounded-hexagonal or barrel-shaped, sometimes tapering proximally between adjacent zooids, separated by a deep groove; 0.34–0.53 mm long (average 50.398 mm, n 525, 3) by 0.21–0.35 mm wide (average 50.270 mm, n 525, 3); basal wall usually incompletely calcified, with a central lumen of varying size, but in some zooids completely calcified; three to five tiny, horizontally elliptical external openings of pore chambers in distal half of each lateral wall and two in distal wall, with corresponding simple openings in lateral walls of proximal halves of surrounding zooids.

Frontal wall. Convex; gymnocyst smooth, narrow laterally, widest and sometimes extensive proximally; frontal shield nearly circular, 0.20–29 mm long (average 50.235 mm, n 520, 2) by 0.19–0.25 mm wide (average 50.223 mm, n 520, 2), composed of 10–14 fused costae, sometimes with a low umbo or median ridge where costae meet; costae smooth and unornamented, curving sharply from base to apex. Costal lumen pores (pelmatidia, or pseudopores) lacking. Between bases of each set of adjacent costae is a circular or subcircular papilla pore several times as large as intercostal pores. Emerging from distalmost papilla pore on each side, lateral to proximal margin of orifice, is a long, tapering setiform papilla ( Figure 8D ). Between adjacent costae is usually a single, tiny, circular intercostal pore (range zero to two); the intercostal pores are arranged in a circle approximately halfway from base to apex of frontal shield. The distalmost pair of costae is generally shorter and sometimes thicker than the rest; between these and just proximal to orifice lies a circular or laterally elliptical lacuna that is usually larger than any of the other frontal pores.

Orifice ( Figure 8A, D ). Semicircular, proximal margin straight, 0.05–0.07 mm long (average 50.058 mm, n 520, 2) by 0.07–0.11 mm wide (average 50.084 mm, n 520, 2); condyles lacking.

Spines ( Figure 8A, C ). Non-ovicellate zooids usually with four short, erect, tubular spines around distal margin of orifice; about 10% of zooids have three or five spines. Ovicellate zooids have a single pair of spines lateral to orifice, sometimes angled medially, appressed to the proximolateral corners of the ovicell.

Ovicell ( Figure 8B–D ). Roughly circular in outline, 0.21–0.24 mm long (average5 0.224 mm, n 515, 2) by 0.23–0.26 mm wide (average 50.234 mm, n 515, 3); raised and globose, or subimmersed; surface smooth, with a low umbo or rounded median ridge; imperforate except for one or two minute median pores on top or toward proximal margin, probably remaining from incomplete closure of ectooecium, difficult to detect without SEM. Ectooecium is confluent with frontal shield of next distal zooid.

Avicularia. Lacking in specimens examined.

Ancestrula . Not observed.

Discussion

Puellina caesia n. sp. is similar to what Osburn (1950) described as Puellina setosa ( Waters, 1899) from the eastern Pacific; characters in common include a similar number of costae; similar zooid measurements; a round frontal shield; a smooth, sometimes extensive proximal gymnocyst; an identical range of oral spine number; an imperforate ovicell often with a longitudinal keel; and no avicularia (Osburn referred to the setiform papillae as ‘‘setose avicularia’’). There are some differences as well; P. caesia has heavier, less distinct costae than figured by Osburn (1950, Plate 29, Figure 4 ); zero to two rather than one to three intercostal pores in addition to the papilla pores; a larger suborificial lumen; and a larger ovicell.

Soule (1959) declared Osburn’s P. setosa as a synonym of Colletosia radiata ( Moll, 1803) , noting that Osburn had overlooked the presence of vicarious avicularia in specimens he identified as P. setosa . However, Osburn included in his P. setosa specimens ranging from the Galapagos Islands to Puget Sound, which suggests he treated more than one species. Furthermore, his description and illustration of nominal P. setosa are so different from those of his C. radiata , and his description so similar to our material, that we suspect at least some of the specimens he examined from Washington and Oregon may have been P. caesia .

Soule et al. (1995) described a new cribrimorph from California, Puellina (Cribrilaria) californiensis , with which they synonymized Osburn’s (1950) P. setosa , in part, and Soule’s (1959) Colletosia radiata . They recognized Puellina (Cribrilaria) radiata ( Moll, 1803) as a Mediterranean species not occurring in the Pacific.

Puellina caesia differs from P. setosa ( Waters, 1899) in having more numerous, less welldefined costae, fewer intercostal pores, and a different mode of ovicell formation. The ovicell of P. caesia is of Type A ( Bishop and Househam 1987), with the ovicell produced during budding of the next distal autozooid and the ectooecium of the ovicell confluent with the frontal wall of that zooid ( Figure 8C ). Except for occasional minute pores, the ovicell of P. caesia is imperforate. The ovicell of P. setosa is of Type C, developing separately from the frontal wall of the next distal zooid, and is clearly perforate. Puellina caesia is superficially similar to P. gattyae ( Landsborough, 1852) , which has similarly thick, rather indistinct costae; however, the latter has fewer (five to nine) costae and a perforate, Type C ovicell ( Bishop and Househam 1987).

Puellina caesia is intermediate between subgenera Puellina (Puellina) and Puellina (Cribrilaria) as defined by Bishop and Househam (1987). The broad proximal gymnocyst, circular frontal shield, lack of avicularia, and two oral spines per ovicellate zooid are all characters of Puellina (Puellina) , whereas the imperforate, Type A ovicell is a character of Puellina (Cribrilaria) . In having this mixture of characters from the two subgenera, Puellina caesia is similar to P. directa Bishop and Househam, 1987 from Britain, though in other characters the two are distinct. P. caesia is unusual among Puellina species in having predominantly four orificial spines per non-ovicellate zooid, rather than five or six.

Distribution

The East Tongass Narrows site near Ketchikan, Alaska is the only known locality .

Figures

Figure 4. (A–D) Cauloramphus tortilis n. sp.: (A) autozooids; unbleached; (B) autozooids, bleached; complete zooid at right is a brooding zooid, with a crescentic kenozooidal ooecium around distal margin; (C) young autozooids near colony margin, showing intermeshing spine bases; bleached; (D) colony margin, showing pore chambers; bleached. (E, F) Tegella aquilirostris (O’Donoghue and O’Donoghue): (E) ovicellate zooids; unbleached; (F) ovicellate zooids; bleached. Scale bars: 500 Mm.

Figure 8. (A–D) Puellina caesia n. sp.: (A) group of autozooids; bleached; (B) group of ovicellate zooids; bleached; (C) colony margin showing several stages of ovicell formation; bleached; (D) enlargement showing setiform papillae proximolateral to orifice; unbleached. Scale bars: 400 Mm (A); 500 Mm (B, C); 200 Mm (D).