| Thallophyca Temporal range: Ediacaran ~ | |
|---|---|
Scientific classification  | |
| Domain: | Eukaryota |
| Clade: | Archaeplastida |
| Division: | Rhodophyta |
| Class: | Florideophyceae |
| Order: | Corallinales |
| Stem group: | Corallinaceae |
| Genus: | † Thallophyca Zhang, 1989 |
| Species | |
Thallophyca is a non-mineralized alga from the Ediacaran period, found within the Doushantuo Formation in 1989. [2] Three distinct species are known, T. ramosa, [2] T. simplicis, [2] and T. corrugata. [3]
Thallophyca are ellipsoidal alga growing up to 1,000–1,500 μm (0.04–0.06 in) in length, with the outer portions of their thallus being enlarged, with notable differentiation into an outer cortex and an inner medulla. [4] [5] The outer cells of the cortex are slightly elongated and spheroidal to polyhedral in shape, and oriented along the thallus, meanwhile the inner cells of the medulla diverge outwards in rows. [5] These inners cells are similar to pseudoparenchyma, due to their tightly packed nature. [5] Some specimens of Thallophyca also show possible reproductive cells within the thallus in the form of clustered islands of larger cells which may be cystocarps, sorus-like structures, and cavities, which are suggested to be similar to conceptacles. [4]
Due to the overall appearance of Thallophyca, it has been compared to extant forms of Coralline algae, and as such has been postured to be an early stem group corallinalean red alga. [4] [5] It was also most likely a benthic alga, inferred from how its lobate protrusions and tissues grew, which can be seen in the large lobes of Thallophyca specimens, which radiate from a centre point. [5]