Minchinellidae Explained

Minchinellidae is a family of calcareous sponges, members of the class Calcarea.^[1] It is the only family in the monotypic order Lithonida. The families Petrobionidae (genus Petrobiona) and Lepidoleuconidae (genus Lepidoleucon)^[2] have also sometimes been placed within Lithonida, though more recently they have been moved to the order Baerida.^[3] Thanks to their hypercalcified structure, minchinellids have a fossil record reaching as far back as the Jurassic Period.

Description

Minchinellids are hypercalcified sponges. They have a robust skeleton of tetractine (four-rayed) calcareous spicules. The tetractine spicules are propeller-shaped, with three curved actines (rays) radiating perpendicular to a straight basal actine. These spicules may be linked by their basal actines or cemented together by calcite. The skeleton is reinforced with layers of loose diapason (tuning fork-shaped) spicules. Minchinellid sponges have a leuconoid canal system.

List of genera

• †Bactronella Hinde, 1884 [Jurassic–Miocene, Holocene?]
• Minchinella Kirkpatrick, 1908 [Holocene]
• Monoplectroninia Pouliquen & Vacelet, 1970 [Holocene]
• †Muellerithalmia Reitner, 1987 [Upper Jurassic]
• Petrostroma Döderlein, 1892 [Cretaceous–Holocene]
• Plectroninia Hinde, 1900 [Jurassic?, Cretaceous–Holocene]
• †Porosphaera Steinmann, 1878 [Cretaceous]
• †Porosphaerella Welter, 1911 [Cretaceous]
• †Retispinopora Brydone, 1912 [Cretaceous–Paleocene]
• †Sagittularia Welter, 1911 [Cretaceous]
• Tulearinia Vacelet, 1977 [Holocene]

External links

• http://www.catalogueoflife.org/col/browse/tree

Notes and References

1. Web site: WoRMS - World Register of Marine Species - Minchinellidae Dendy & Row, 1913. www.marinespecies.org. en. 2019-03-20.
2. 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. .
3. Treatise on Invertebrate Paleontology Part E, Revised. Porifera, Volumes 4 & 5: Hypercalcified Porifera, Paleozoic Stromatoporoidea & Archaeocyatha, liii + 1223 p., 665 figs., 2015, available here. .