Australia: The Land Where Time Began

A biography of the Australian continent 

The receptaculitids are a group of "problematica" that lived from the Ordovician to the Devonian. They are known as "Sunflower Corals" because of their 'beautiful and complex structure' (White, 1993). They are usually classified as a family of the order Dasyclydales of the Green Algae. According to the consensus of opinion they are not related to either corals or sponges. Receptaculitids are pear-shaped to semi-globular, 1-30 cm in diameter. Spindle-shaped pillars connect the 2 layers of their walls. They have been divided into 2 genera, Receptaculites and Ischadites.

The outer and inner walls of Receptaculites are composed of rhomboidal plates, arranged in an ascending spiral, lying exactly opposite each other, connected by the pillars.

The spiral nature of the structure in Ischadites can be seen in a photograph of the external surface (White, 1993, p. 100). 4 projections which form a cross at the top of each pillar support the outer plates.

Plates are lacking on the inner wall (an undivided layer) of Ischadites. The support of the outer plates is 3-pronged. The outer plates are spirally arranged as seen in Receptaculites.

They are present only in rocks forming in low latitudes, up to 20^o north and south of the palaeo-Equator, making them indicators of environment type, as they lived only in warm, shallow marine environments.

Sources & Further reading

1. Mary E. White, 1993, The Nature of Hidden Worlds: Animals and Plants in prehistoric Australia and New Zealand, Reed