Sphaerocoeliidae Explained

Sphaerocoeliidae is an extinct family of calcareous sponges, the only family in the monotypic order Sphaerocoeliida. Sphaerocoeliids are one of several unrelated sponge groups described as "sphinctozoans", with a distinctive multi-chambered body structure. Sphaerocoeliids persisted from the Permian to the Cenomanian stage of the Cretaceous, a longer period of time than most other "sphinctozoans". Sphaerocoeliids make up the majority of calcareous "sphinctozoans", as well as a large portion of post-Triassic "sphinctozoan" diversity.^{[1] [2]} "Sphinctozoans" and the similar "inozoans" were historically grouped together in the polyphyletic order Pharetronida.

In general form, sphaerocoeliids are cylindrical, as a chain of dome-shaped chambers stacked up on each other. Each layer is pierced by a central osculum (outflow vent), which has the form of a simple hole. Sphaerocoeliids are hypermineralized, with a skeleton of loose calcareous spicules cemented together in calcite walls.

Genera

• †Barroisia Munier-Chalmas, 1882 [Jurassic<ref name=":1" />–Cretaceous ([[Aptian]]–Cenomanian)]
• †Sphaerocoelia Steinmann, 1882 [Permian–Cretaceous (Cenomanian)]
• †Sphinctonella Hurcewicz, 1975 [Jurassic ([[Oxfordian (stage)|Oxfordian]])]
• †Thalamopora Roemer, 1840 [Jurassic<ref name=":1" />–Cretaceous (Cenomanian)]
• †Tremacystia Hinde, 1884 [Cretaceous ([[Albian]]–Cenomanian)]

Notes and References

1. Treatise on Invertebrate Paleontology Part E, Revised. Porifera, Volume 3: Classes Demospongea, Hexactinellida, Heteractinida & Calcarea, xxxi + 872 p., 506 fig., 1 table, 2004, available here. .
2. Treatise on Invertebrate Paleontology Part E, Revised. Porifera, Volumes 4 & 5: Hypercalcified Porifera, Paleozoic Stromatoporoidea & Archaeocyatha, liii + 1223 p., 665 figs., 2015, available here. .