Pentapora fascialis is a large erect bryozoan, known from the Mediterranean. Colonies attach to the substrate via an extensive encrusting base and develop narrow strap-like branches. Colonies are deep orange in colour when alive, fading to a pale buff after death.

Pentapora foliacea, commonly known as “Potato Crisp Bryozoan” or “Ross Coral” is the largest bryozoan inhabiting British waters. Colonies attach to the substrate via an extensive encrusting base and develop folded three-dimensional branching plates. Plates are composed of two layers of autozooids arranged back-to-back. Colonies are deep orange in colour when alive, fading to a pale buff after death. The species is found in the north-eastern Atlantic.

There is continuing disagreement about whether Pentapora foliacea and Pentapora fascialis are separate species, with the majority of the more recent work, up until Lombardi et al (2010), tending to regard P. foliacea as a junior synonym of P. fascialis. Lombardi et al (2010) again split the two species pending the results of molecular analysis, which is currently being undertaken

 A large, erect bryozoan deep orange in colour. The colony is attached to the substratum by an encrusting base and forms a mass of repeatedly dividing sheets in an open honeycomb structure. The edges of the sheets are wavy and convoluted. Pentapora fascialis has a growth rate of approximately 2 cm per year and lives for up to ten years. Colonies can reach up to 40 cm in diameter (more typically up to 20 cm across) and 10 cm in height. When dead, the deep orange colour fades to a pale buff.Sometimes misleadingly called "ross coral". The above taxonomy uses the most recent nomenclature according to Hayward & Ryland (1999). The Species Directory of the British Isles (Howson & Picton, 1997) placed Pentapora fascialis in the family Hippoporinidae under the species name Pentapora foliacea. Older classification schemes used the species Lepralia foliacea, e.g. the Plymouth Marine Fauna (Marine Biological Association 1957) and Bruce et al. (1963).

This is the largest bryozoan to be found around our coasts, growing to 40cm or more across. The colony consists of a series of brittle plates joined to each other to form a domed or hemispherical colony. Small colonies start by encrusting the rock and then growing a series of upright plates. No other species in the area forms large upright lamellate colonies. Smittina landsborovii is normally an encrusting species, but can grow small two-sided, convoluted plates which look like the start of a Pentapora colony.

Belgian Exclusive Economic Zone, Cap Gris Nez, English Channel, European waters (ERMS scope), Portuguese Exclusive Economic Zone, Spanish Exclusive Economic Zone, United Kingdom Exclusive Economic Zone, Wenduine

Pentapora fascialis is distributed throughout the Mediterranean, from the Strait of Gibraltar in the west to the Aegean in the east.

Pentapora foliacea is distributed in the north-eastern Atlantic from St. Kilda south to the coast of Morocco. It is found in the English Channel as far east as Hastings. Mediterranean records require reassessment owing to the similarities of P. foliacea to Pentapora fascialis.

A common species in the southern part of Ireland and the British Isles, becoming more scarce in Scotland, but recorded as far north as Lewis in the Outer Hebrides.

Colonies are commonly 40 cm in diameter. Autozooids range in size from 0.67-0.93 by 0.28-0.44 mm.

Colonies developing erect, narrow, strap-like, bifurcating branches from an encrusting base. Early astogeny unknown.

Autozooids longer than wide, 0.68-1.28 mm long (mean 0.88 ± 0.13mm; N=20) by 0.32-0.54 wide (mean 0.42 ± 0.05 mm; N=20) in recent samples, 0.73-0.79 mm long (mean 0.75 ±  0.03 mm; N= 20) in Pliocene fossils, roughly rectangular in shapes, arranged quincuncially with distinct boundaries becoming obscured during later ontogeny. Frontal shield lepralioid, granular, with areolar pores and pseudopores, developing knobs as thickening increases during ontogeny. Primary orifice 0.17-0.25 mm long (mean 0.21 ± 0.02 mm; N=20) by 0.14- 0.21 mm wide (mean 0.18 ± 0.01 mm; N = 20) in recent material, 0.13-0.19 long (mean 0.17 ± 0.02 mm; N=20) by 0.11-0.17 mm wide (mean 0.15 ± 0.02; N=20) in Pliocene fossils, a pair of down turned condyles between anter and poster; secondary orifice slightly oval to trifoliate, following the development of lappets. Operculum brown, lustrous. Oral spines lacking in recent material, but very occasionally observed lateral to the orifice in Pliocene fossils. Basal walls with short median septum extending distally from transverse vertical walls. Ovicells globular or elliptical, wider than long, 0.19-0.25 mm long (mean 0.32 ± 0.03 mm; N=20) by 0.24-0.35 mm wide (mean 0.32 ± 0.03; N=20) wide, pores few scattered, becoming occluded by secondary calcification.

Avicularia dimorphic, adventitious, suboral proximally directed. Normal avicularia small, inclined at a high angle to frontal surface, longer than wide, 0.08-0.12 mm long (mean 0.09 ± 0.01 mm; N=10) by 0.07-0.09 mm wide (mean 0.08-0.003 mm; N=10) in recent material, 0.08-0.11 long (mean 0.09 ± 0.01 mm; N=10) by 0.07-0.09 mm wide (mean 0.08 ± 0.01; N=10) in Pliocene fossils; rostrum short, semielliptical; orifice 0.050 ± 0.005 mm long (N = 10) by 0.030 ± 0.007 mm wide (N = 10); crossbar averaging 0.050 ± 0.004 mm long (N = 10). Giant avicularia occasionally replacing normal avicularia; longer than wide, 0.29–0.42 mm long (mean 0.34 ± 0.07 mm; N = 5) by 0.17–0.20 mm wide (mean 0.11 ± 0.01 mm; N = 5) in recent material, 0.26–0.41 mm long (mean 0.32 ± 0.05 mm; N = 5) by 0.13–0.23 mm wide (mean 0.18 ± 0.05 mm; N = 5) in Pliocene fossils; rostrum spatulate, palate deep; orifice 0.13 ± 0.04 mm long by 0.070 ± 0.001 mm wide (N = 5); crossbar averaging  0.110 ± 0.001 mm long (N = 5).

Lombardi et al (2010)

Colonies developing three-dimensional box-like growth comprising folded and anatomosing bilamellar plates from an extensive encrusting base. Early astogeny unknown.

Autozooids longer than wide, 0.67-0.93 mm long (mean 0.81 ± 0.09 mm; N= 20) by 0.28-0.44 mm wide (mean 0.36 ± 0.04 mm; N=20), roughly rectangular in shape, initially elongate, but becoming more equidimensional during ontogeny; arranged quincuncially; zooidal boundary walls salient. Frontal shield lepraliod, granular, with areolar pores and pseudopores, both becoming less distinct through wall thickening during ontogeny, which also obscures zooidal boundaries. Primary orifice 0.11-.020 mm long (mean 0.18 ± 0.2 mm; N=15) by 0.16-0.19 mm wide (mean 0.18 ± 0.01 mm; N=15), a pair of downturned condyles between anter and poster; secondary orifice slightly oval to trifoliate because of the development of lappets. Operculum brown, lustrous. No oral spines. Basal walls with short median septum extending distally from transverse wall. Multiporous septula in lateral and transverse vertical walls near their bases; circular to ovoidal, shallow muscle impressions may be visible close to septula. Ovicell elliptical, wider than long, 0.21-0.25 mm long (mean 0.23 ± 0.01 mm; N=20) by 0.27-0.35 mm wide (mean 0.31 ± 0.02; N=20), a few scattered pores arranged in a band proximally above orifice, becoming overgrown by secondary calcification.

Avicularia monomorphic, adventitious, suboral, usually placed on an umbo, inconspicuous, small, longer than wide, 0.09-0.11 mm long (mean 0.100 ± 0.005 mm; N=10) by 0.08-0.10 mm wide (0.090 ± 0.007 mm; N=10); rostrum semielliptical; orifice 0.050 ± 0.005 mm long by 0.030 ± 0.004 mm wide; crossbar averaging 0.060 ± 0.008 mm long. Giant avicularia not observed, presumed lacking.

(Lombardi et al., 2010)

Depth range based on 132 specimens in 1 taxon.
Water temperature and chemistry ranges based on 73 samples.

Environmental ranges
  Depth range (m): 8.85 - 96
  Temperature range (°C): 9.899 - 17.140
  Nitrate (umol/L): 0.211 - 8.618
  Salinity (PPS): 34.692 - 38.444
  Oxygen (ml/l): 5.513 - 6.346
  Phosphate (umol/l): 0.095 - 0.682
  Silicate (umol/l): 1.247 - 5.963

Graphical representation

Depth range (m): 8.85 - 96

Temperature range (°C): 9.899 - 17.140

Nitrate (umol/L): 0.211 - 8.618

Salinity (PPS): 34.692 - 38.444

Oxygen (ml/l): 5.513 - 6.346

Phosphate (umol/l): 0.095 - 0.682

Silicate (umol/l): 1.247 - 5.963
 
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The species usually colonises boulders or bedrock, with small colonies occasionally found on kelp holdfasts. Pentapora fascialis is found in subtidal waters and is most common below 18 m and often abundant between 25-35 m.

The species usually colonises boulders or bedrock, with small colonies occasionally found on kelp holdfasts. Pentapora foliacea is found in subtidal waters and is most common below 18 m and often abundant between 25-35 m.

 Pentapora fascialis colonies grow on bedrock or large boulders in current swept areas, often surrounded by gravel and scoured by coarse sand. They may colonize coarse gravel and pebbles but do not grow to large colonies.

This species is most common in sand-scoured habitats attached to bedrock or boulders, often surrounded by coarse gravel