Lesson plan
Surangular
, showing location of surangular Dimetrodon, showing location of surangular The surangular is a jaw bone found in most land vertebrates, except mammals. The surangular makes up the upper portion of the back half of the outside of the lower jaw, behind the dentary, above the angular, and outside the articular. It is the main component of the outer wall of the adductor fossa, where the major jaw-closing muscles attach to the mandible. The surangular is ancestrally the posteriormost in the series of infradentary bones, which line the outside of the mandible below and behind the dentary bone. It is also known as the fourth infradentary in early sarcopterygians, in which the infradentary series comprises four bones, the first being the splenial, the second the postsplenial, and third being the angular. In archosaurs there is an opening, the external mandibular fenestra, found between the surangular, dentary, and angular. In some eucynodonts, the surangular contacted the squamosal to form part of the jaw joint, a characteristic that historically had been interpreted as a predecessor of the dentary-squamosal joint of mammals. The surangular was reduced to a tiny splint as part of the evolution of mammalian auditory ossicles from other bones involved in the jaw joint, and absent in most mammals.
Article summary
, showing location of surangular Dimetrodon, showing location of surangular The surangular is a jaw bone found in most land vertebrates, except mammals. The surangular makes up the upper portion of the back half of the outside of the lower jaw, behind the dentary, above the angular, and outside the articular. It is the main component of the outer wall of the adductor fossa, where the major jaw-closing muscles attach to the mandible. The surangular is ancestrally the posteriormost in the series of infradentary bones, which line the outside of the mandible below and behind the dentary bone. It is also known as the fourth infradentary in early sarcopterygians, in which the infradentary series comprises four bones, the first being the splenial, the second the postsplenial, and third being the angular. In archosaurs there is an opening, the external mandibular fenestra, found between the surangular, dentary, and angular. In some eucynodonts, the surangular contacted the squamosal to form part of the jaw joint, a characteristic that historically had been interpreted as a predecessor of the dentary-squamosal joint of mammals. The surangular was reduced to a tiny splint as part of the evolution of mammalian auditory ossicles from other bones involved in the jaw joint, and absent in most mammals.
Key claims
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Discussion questions
- Summarise the article in your own words. Which single claim would you verify first, and why?
- Which claim in this article is most likely to be revised as the sources update? How would you check its current status?
- If two sources disagreed about one of these facts, what would you need in order to trust one over the other?
Bibliography
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Key claims and bibliography are generated from the same tracked claims and sources as the article page.