Amansia roycei Huisman

Scientific Description

Habit and structure. Thallus 13 cm tall, deep red (ventral surface light brown due to seemingly obligate encrusting bryozoans), arising from a discoid holdfast, with flat axes (becoming terete near the base due to thickening of the midrib) that are irregularly alternately branched from the margins. Primary axes 1–2 mm wide, bearing lateral branches every 2–5 mm, these similar in form to primary axes but slightly narrower and tapering to 1 mm wide near the inrolled or flat apices. Determinate marginal spines regularly to occasionally present in place of lateral branches. Proliferous branches commonly arising from the thickened midrib near the thallus base. Structure with surface cells in regular horizontal tiers of longitudinally elongate cells, 100–135 µm long, 20–35 µm wide in surface view; dorsal and ventral tiers aligned near the midrib but becoming displaced laterally. Each dorsal pericentral cell producing a pseudopericentral cell laterally; ventral pericentral cell dividing transversely or obliquely towards the proximal end of the cell.

Reproduction. Not observed.

Distribution. Known from the Houtman Abrolhos Islands, Ningaloo Reef, Barrow Island and the Montebello Islands, Western Australia.

Habitat. Epilithic in the subtidal to 37 m depth.

[After J.M. Huisman in Algae of Australia: Marine Benthic Algae of North-western Australia, 2. Red Algae: 486–487 (2018)]