Publication Date:
2008-10-17
Description:
Among the morphological changes that occurred during the 'fish-to-tetrapod' transition was a marked reorganization of the cranial endoskeleton. Details of this transition, including the sequence of character acquisition, have not been evident from the fossil record. Here we describe the braincase, palatoquadrate and branchial skeleton of Tiktaalik roseae, the Late Devonian sarcopterygian fish most closely related to tetrapods. Although retaining a primitive configuration in many respects, the cranial endoskeleton of T. roseae shares derived features with tetrapods such as a large basal articulation and a flat, horizontally oriented entopterygoid. Other features in T. roseae, like the short, straight hyomandibula, show morphology intermediate between the condition observed in more primitive fish and that observed in tetrapods. The combination of characters in T. roseae helps to resolve the relative timing of modifications in the cranial endoskeleton. The sequence of modifications suggests changes in head mobility and intracranial kinesis that have ramifications for the origin of vertebrate terrestriality.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Downs, Jason P -- Daeschler, Edward B -- Jenkins, Farish A Jr -- Shubin, Neil H -- England -- Nature. 2008 Oct 16;455(7215):925-9. doi: 10.1038/nature07189.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Academy of Natural Sciences of Philadelphia, 1900 Benjamin Franklin Parkway, Philadelphia, Pennsylvania 19103, USA. downs@ansp.org〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/18923515" target="_blank"〉PubMed〈/a〉
Keywords:
Animals
;
*Biological Evolution
;
*Ecosystem
;
Fishes/*anatomy & histology/physiology
;
*Fossils
;
Models, Biological
;
Skull/*anatomy & histology/physiology
Print ISSN:
0028-0836
Electronic ISSN:
1476-4687
Topics:
Biology
,
Chemistry and Pharmacology
,
Medicine
,
Natural Sciences in General
,
Physics
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