Opisthocoelian is a term commonly used in palaeontology to describe a type of vertebral centrum. The word is composed of four syllables: opistho, co, ce and lian. The stressed syllable is "ce", hence the IPA phonetic transcription is [əpɪstˈhɑʊsi:liən]. The initial "o" is pronounced with the schwa sound, whereas the "i" after "ce" is pronounced as a long "i" sound. The suffix "-lian" is often used in taxonomy to indicate a belonging to a certain group or class.
Opisthocoelian is an adjective used in biology and paleontology to describe a specific anatomical characteristic found in certain vertebrate animals, particularly reptiles and dinosaurs. It refers to a type of centrum, which is the cylindrical or block-like body of a vertebra.
The term opisthocoelian specifically describes a centrum that is concave on the posterior side, or towards the tail end of the animal, while the anterior side, or towards the head, is typically convex or flat. This results in a unique shape resembling a hollowed-out cylinder or a cup.
This anatomical feature is of particular interest to scientists studying ancient reptiles and dinosaurs because it can provide important clues about their physiology, biomechanics, and evolutionary relationships. The opisthocoelian vertebral centrum is believed to have certain biomechanical advantages, potentially facilitating increased flexibility and range of motion in the tail region.
Opisthocoelian vertebrae are fairly common finds in the fossil record, especially among sauropod dinosaurs, such as the iconic Brachiosaurus and Diplodocus. These dinosaurs had long necks and tails, and their opisthocoelian vertebrae likely played a role in supporting and balancing their massive bodies.
Overall, the term opisthocoelian serves as a useful descriptor for a specific and distinct vertebral anatomical feature observed in certain reptiles and dinosaurs, allowing scientists to accurately categorize and study these fascinating creatures from the past.
Having the vertebrae hollow at the back part.
Etymological and pronouncing dictionary of the English language. By Stormonth, James, Phelp, P. H. Published 1874.
The word "opisthocoelian" is derived from two Greek words: "opistho" meaning "behind" or "at the back", and "coelus" meaning "cavity" or "hollow". These roots are then combined with the suffix "-ian" to form the adjective "opisthocoelian".
In the context of paleontology and vertebrate anatomy, opisthocoelian refers to a specific type of vertebral centrum, which is the cylindrical body of a vertebra. Opisthocoelian vertebrae have a concave articular surface at the back, meaning that it is the posterior end of the centrum that is depressed or curved inward. This arrangement is often observed in certain dinosaur species and other extinct reptiles.