Montlivaltia Fossil Finger Coral Sea Exacoral Mesozoic Jurassic Collection (2)

Finger Fossil Sea Coral Solitary mm 33 x 26 x 25 gr 31.5 Montlivaltia induta Benthic Invertebrata Sessile Coelenterata Cnidaria Anthozoans Hexacorals Prehistoric Extinct Mesozoic Cretaceous Collectng Paleontology Museum.

Remarkable fossil find of Exacorallia Scleractinia Thecosmiliidae from the Lower Cretaceous of Madagascar, representative collectible specimen of excellent quality and in perfect state of preservation, with evident surface details of the finger-shaped rugose reticulated structure of the aragonite skeleton.
Only a piece, as in photos.
We recommend the small box at this link to contain and display it.

Montlivaltia is an extinct genus of bilaterally symmetrical Cnidarian hard corals with a mineralized aragonite skeleton belonging to the Thecosmiliidae family (renamed from Montlivaltiidae), which appeared in the Triassic until the Tertiary Era.
This genus includes more than 90 recognized species, with both sexual and asexual reproduction. Their remains formed shallow marine sediments.
This solitary coral was 2.5 to 9 cm long, and was conical or flattened. The surface was wrinkled with many septa. The outer sides were notched or ribbed. It contained many smaller herringbone partitions.

Very little is known about fossil specimens of the Scleractinian Hexacorals, which first appeared in the Middle Triassic (240 million years ago). It was not until 25 million years later that they became major reef builders, their success probably the result of collaboration with symbiotic algae. Nine suborders existed at the end of the Triassic and three more appeared in the Jurassic (200 million years ago), with an additional suborder appearing in the Middle Cretaceous (100 million years ago). Some may have developed from a common ancestor, a skeletonless anemone-like coral or a wrinkled coral. A tetracoral rugose coral, however, seems an unlikely common ancestor because these corals had skeletons of calcite rather than aragonite, and the septa were arranged serially rather than cyclically. However, it is possible that the similarities between scleractinians and rugosans are due to a non-skeletonized common ancestor in the Early Paleozoic. It appears that skeletal genesis may have been associated with the development of symbiosis and reef formation and may have occurred on more than one occasion. DNA sequencing appears to indicate that scleractinian corals are a monophyletic group.
Early scleractinians were not reef builders, but were small, phaceloid (elongated tube-shaped colony), or solitary individuals. Scleractinian corals probably reached their maximum diversity in the Jurassic and nearly disappeared in the mass extinction event at the end of the Cretaceous, with approximately 18 of 67 genera surviving. Recently discovered Paleozoic corals with aragonitic skeletons and cyclic septal insertion - two features that characterize Scleractinia - have strengthened the hypothesis of an independent origin of Scleractinia.