Basioccipital
The basioccipital is a bone present in the posterior region of the skull in vertebrates. It encloses the ventral margin of the foramen magnum.[1] It is a part of the chondrocranium.[2]
Evolution
[edit]Unlike most of the skull, the basioccipital develops from somites, which otherwise develop into the vertebrae.[3][4] This has led to the hypothesis that the basioccipital has its evolutionary origin as a modified vertebra.[1] However, this hypothesis has been contested on the basis of embryonic evidence in actinopterygian fishes.[5][6]
The basioccipital is present in basal amniotes, where it forms the majority of the occipital condyle. This is the role it takes in most modern and fossil sauropsids.[1]
In humans, the basioccipital fuses with the supraocipitals and the exoccipitals to form the basilar part of the occipital bone.[2]
References
[edit]- 1 2 3 Romer, A. S. (1956). Osteology of the Reptiles. University of Chicago Press.
- 1 2 Kardong, Kenneth (2015). Vertebrates: Comparative Anatomy, Function (7th ed.). McGraw-Hill.
- ↑ Couly, Gérard F.; Coltey, Pierre M.; Douarin, Nicole M. Le (1993-02-01). "The triple origin of skull in higher vertebrates: a study in quail-chick chimeras". Development. 117 (2): 409–429. doi:10.1242/dev.117.2.409. ISSN 0950-1991. PMID 8330517.
- ↑ Kant, Rajiv; Goldstein, Ronald S. (1999-12-15). "Plasticity of Axial Identity among Somites: Cranial Somites Can Generate Vertebrae without Expressing Hox Genes Appropriate to the Trunk". Developmental Biology. 216 (2): 507–520. doi:10.1006/dbio.1999.9512. ISSN 0012-1606. PMID 10642789.
- ↑ Britz, Ralf; Johnson, G. David (2010). "Occipito-vertebral fusion in actinopterygians: conjecture, myth and reality. Part 1: Non-teleosts". hdl:10088/9748.
{{cite journal}}: Cite journal requires|journal=(help) - ↑ Johnson, G. David; Britz, Ralf (2010). "Occipito-vertebral fusion in Actinopterygians: conjecture, myth and reality. Part 2: Teleosts". Origin and Phylogenetic Interrelationships of Teleosts: 95–110.