Domed Photosagnia

Domed Photosagnia(Porphyrotholus rotundum)
Species Information
Creator	Ethos More by this creator
Week and Generation	2/12
Habitat	East Darwin Temperate Beach, East Darwin Temperate Coast
Size	20-50 µm diameter (up to 50cm wide, 30cm tall colonies)
Support	Unknown
Diet	Photosynthesis, Scavenger
Respiration	Unknown
Thermoregulation	Unknown
Reproduction	Binary Fission
Taxonomy
Genus	Porphyrotholus
Species	Porphyrotholus rotundum
Ancestor	Darwinian Photosagnia
Descendants	Forest Purplestem, Overnight Mycostrum, Purple Spheres
Domed Photosagnia is the ancestor of a major clade, Purpuraphyta.

Domed Photosagnia split from its ancestor, Darwinian Photosagnia, which would occasionally drift north onto the East Darwin Temperate Beach. In this more competitive environment, colonies developed primitive cell differentiation triggered by environmental cues within the mats. Surface cells are more specialized for photosynthesis, those inside have more water storage which allows survival further from the shore, and those at the bottom and edges are more detritivorous to capture organic matter and available nutrients.

These adaptations allow mats to spread several meters beyond the high tide line, avoiding competition and predation. The drier conditions of the inner beaches cause mats to have thicker cell walls, more water storage cells, and a more compact, round dome shape. Otherwise, they are much like their ancestor and can survive as free-floating single cells in seawater.