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Pentapora fascialis

General description: 

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.

Diagnostic description: 

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)

Distribution: 

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

Habitat: 

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.