Rugosa vs. Tabulata

Attribute	Rugosa	Tabulata
Time Period	Paleozoic era	Paleozoic era
Structure	Corallites with septa	Corallites with tabulae
Growth Form	Solitary or colonial	Colonial
Reproduction	Sexual and asexual	Sexual and asexual

Introduction

Rugosa and Tabulata are two major orders of extinct corals that lived during the Paleozoic era. While both belong to the class Anthozoa, they exhibit distinct characteristics that set them apart from each other. In this article, we will explore the attributes of Rugosa and Tabulata, highlighting their differences and similarities.

Physical Characteristics

Rugosa corals are solitary or colonial, with a cylindrical or conical shape. They have a central cup-like structure called a calyx, which houses the polyp. The walls of the calyx are made up of septa, which are vertical partitions that divide the calyx into chambers. In contrast, Tabulata corals are exclusively colonial and have a tabular or encrusting growth form. They lack a central calyx and instead have horizontal partitions called tabulae that divide the corallites.

Skeletal Structure

The skeletal structure of Rugosa corals is composed of calcite, a form of calcium carbonate. The septa in Rugosa corals are thick and often have granules or teeth on their edges. In Tabulata corals, the skeletal structure is also made of calcite, but it is more delicate and composed of thin, horizontal tabulae. The tabulae in Tabulata corals are often perforated, giving them a lace-like appearance.

Reproductive Strategies

Rugosa corals reproduce sexually by releasing eggs and sperm into the water, where fertilization occurs. They can also reproduce asexually through budding, where new polyps grow from the base of the parent polyp. Tabulata corals primarily reproduce asexually through budding, with new corallites forming from the edges of existing ones. Some Tabulata corals also have the ability to reproduce sexually by releasing gametes into the water.

Ecological Role

Rugosa corals were important reef builders during the Paleozoic era, forming large, reef-like structures in shallow seas. These reefs provided habitat for a diverse range of marine organisms. Tabulata corals also played a role in reef formation, but they were more common in deeper, calmer waters compared to Rugosa corals. Tabulata reefs were often found in areas with low sedimentation rates.

Extinction

Both Rugosa and Tabulata corals went extinct at the end of the Permian period, around 250 million years ago. The exact cause of their extinction is still debated among scientists, but factors such as climate change, ocean acidification, and competition with other organisms are believed to have played a role. The disappearance of these corals had a significant impact on marine ecosystems, leading to the decline of reef-building activities during the Mesozoic era.