Pacificincola Liu and Liu, 1999

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 : 3747-3749

Genus Pacificincola Liu and Liu, 1999

Pacificincola insculpta ( Hincks, 1882)

( Figure 17A–D )

Schizoporella insculpta Hincks 1882, p 251 ; 1883, p 447, Plate 17, Figure 5 .

Schizoporella insculpta: Robertson 1900, p 326 ; 1908, p 290, Plate 20, Figures 46, 47;

O’Donoghue and O’Donoghue 1923, p 36; 1925, p 102; 1926, p 57.

Hippodiplosia insculpta: Osburn 1952, p 341 , Plate 40, Figures 1 , 2 (in part); McCain and

Ross 1974, p 14.

Hippoporina insculpta: Soule et al. 1995, p 179 , Plate 64.

Description

Colony. Live colonies orange; primarily unilaminar and encrusting, but capable of rising in irregular, bilaminar lobes and frills; to several centimetres in maximum dimension.

Zooids. Rounded-hexagonal, barrel-shaped, or oval; widest at orifice, narrower proximally, tapering or truncate, 0.58–0.95 mm long (average 50.722 mm, n 530, 3) by 0.25–0.45 mm wide long (average 50.341 mm, n 530, 3); zooids of two types ( Figure 17A ), male (terminology of Nielsen 1981) with a smaller orifice, and female with a larger orifice; the latter have an ovicell or the potential to produce one. Young colonies can be composed entirely of non-fertile zooids; as the colony becomes reproductive, it produces a marginal zone of non-fertile interspersed with fertile zooids, the latter producing ovicells.

Frontal wall. Slightly convex; vitreous, texture smooth or finely tuberculate; uniformly perforated with large pores except just proximal to orifice, where there is a raised crescentic arch with a distal cavity covered by ectocyst.

Orifice ( Figure 17C ). With a semicircular anter separated from a broad poster by prominent, sharp, shelf-like condyles; longer than broad and larger in female zooids, 0.20–0.38 mm long (average 50.275 mm, n 515, 3) by 0.23–0.25 mm wide (average 50.241 mm, n 515, 3); broader than long and smaller in male zooids, 0.16–0.20 mm long (average 50.183 mm, n 515, 3) by 0.18–0.23 mm wide (average 50.200 mm, n 515, 3); surrounded by a raised rim; peristome negligible.

Spines and avicularia. Lacking.

Ovicell ( Figure 17B ). Raised, globose, conspicuous, overlying the frontal wall of next distal zooid; texture finely tuberculate; imperforate, with coarse ridges converging from margin to proximal midline; 0.30–0.50 mm long (average 50.390 mm, n 515, 3) by 0.29–0.50 mm wide (average 50.390 mm, n 515, 3).

Ancestrula . One observed ( Figure 17D ), 0.35 mm long by 0.28 mm wide; orifice subcircular; budding a triplet of daughter zooids, one distally and two laterally, with the latter orientated distolaterally but curving proximally around the ancestrula, nearly meeting in the proximal midline.

Remarks

We observed P. insculpta only at East Tongass Narrows, where it was commonly attached to algae such as Rhodomela larix in crevices. Nielsen (1981) described the morphology and reproduction of this species in detail, but expressed doubts about its placement ( Winston 1979; Soule et al. 1995) in the genus Hippoporina . Liu and Liu (1999) erected a new family ( Pacificincolidae ) and genus ( Pacificincola ) for a group of three Pacific species, including P. perforata ( Okada and Mawatari, 1937) as the type species of the genus, P. insculpta ( Hincks, 1882) , and P. mexicana ( Soule et al., 1995) . Characters given by Liu and Liu (1999) as defining the family and genus include a bell-shaped orifice; evenly perforate frontal walls; imperforate hyperstomial ovicells with radial ribs; and a subcircular ‘‘ascus’’ present within a suboral umbo. By ‘‘ascus’’, these authors meant ‘‘ascopore’’, yet neither does this term correctly reflect the nature of the subcircular opening on the distal face of the suboral umbo. Nielsen (1981) showed this opening in P. insculpta to be the aperture of a small heterozooid containing a reduced polypide and connecting to the autozooid by a pair of pore plates; the function of this heterozooid is unknown.

Distribution

Robertson (1908) gave the range of this species as Sitka, Alaska to the Coronados Islands, southern California; however, Osburn (1952) reported it from as far south as Costa Rica, noting that in the southern part of its range zooids were smaller and neater in appearance. Soule et al. (1995) recognized P. insculpta as a more northerly species extending from Sitka to southern California, and described a new species, P. mexicana , corresponding to Osburn’s southern form, extending from southern California to Costa Rica.

Figures

Figure 1. Membranipora villosa Hincks. (A) ‘‘Membranacea’’ form, weakly bleached; (B) ‘‘serrilamella’’ form, bleached; (C) ‘‘villosa’’ form; unbleached; note acute chitinous spines at proximal corners and cuticular spines on frontal membranes; (D) ‘‘villosa’’ form; same colony as (C) after bleaching, showing weakly denticulate cryptocyst; (E) ‘‘villosa’’ form from Sitka, Alaska; weakly bleached specimen with zooids showing both denticulate cryptocyst and cuticular spines on frontal membrane; (F) ‘‘villosa’’ form from Sitka, Alaska; same colony as (E), with zooids showing coarse, highly denticulate cryptocyst. Scale bars: 500 Mm (A–C, E, F); 400 Mm (D).

Figure 5. (A–D) Tegella horrida (Hincks): (A) group of ovicellate zooids near colony margin, well separated with scattered lacunae between them; bleached; (B) group of heavily calcified ovicellate zooids, the avicularium proximal to opesia completely immersed; bleached; (C) group of ovicellate zooids; unbleached; (D) autozooid (left) and intramural reparative avicularium (right); bleached. (E, F) Hincksina longiavicularia Gontar: (E) group of autozooids and spatulate vicarious avicularia; unbleached; (F) several ovicellate zooids; unbleached. Scale bars: 500 Mm (A–C, E); 200 Mm (D, F).

Figure 17. Pacificincola insculpta (Hincks): (A) group of zooids showing two orifice sizes; zooids with large orifice are capable of forming ovicells; (B) ovicellate zooids; (C) enlargement of orifice of non-ovicellate zooid, showing suboral umbo and aperture of suboral heterozooid; (D) ancestrula and periancestrular zooids. All specimens bleached. Scale bars: 500 Mm (A, B, D); 200 Mm (C).