Palaeoaplysina

Palaeoaplysina Temporal range: Upper Carboniferous –Lower Permian PreЄ Є O S D C P T J K Pg N
Scientific classification
Phylum:	Rhodophyta
Class:	Florideophyceae
Stem group:	Corallinales
Order:	†Archaeolithophyllales (?)
Family:	†Palaeoaplysinaceae
Genus:	†Palaeoaplysina

Palaeoaplysina is a genus of tabular, calcified fossils that are a component of many Late Palaeozoic reefs. The fossil acted as a baffle to trap sediment. Historically interpreted as a sponge or hydrozoan, recent studies are converging to its classification in the coralline stem group, placing it among the red algae.

Morphology

The thalloid organism had a series of internal canals opening on one side of the body (presumably the upper side), and volcano-like protuberances on that same side inviting comparison to filter-feeding organisms. On the other hand, it seems to have had a calcified cellular make up akin to that of the coralline reds, suggesting that it was either a stem-group coralline or a coralline-encrusted filter feeder.

Distribution

The organism is widespread in the tropical and near-tropical margin of the Laurentian continent (45–15°N), but is not found elsewhere. Its oldest reported occurrence is Middle Pennsylvanian (mid- to late Moscovian) and youngest is the late Sakmarian. It acts as an important reservoir rock for oil deposits.

See also

• Coralline algae#Evolution
• Other stem-group corallines:
  • Arenigiphyllum (Ordovician)
  • Petrophyton (Ordovician : Caradoc)
  • Graticula (Silurian : Wenlock)
  • Halysis (Ordovician)
  • Archaeolithophyllum (Pennsylvanian)
  •  ?Maimonachaetetes (Mississippian)
  •  ?Palaeoaplysina (Pennsylvanian – Permian; possibly an animal)
  •  ? Solenoporaceae (Ordovician)