Palatoquadrate in a Devonian fish Eusthenopteron Evidence of its dual origin
作者:
Z. Roček,
期刊:
Journal of Zoological Systematics and Evolutionary Research
(WILEY Available online 1993)
卷期:
Volume 31,
issue 1
页码: 38-46
ISSN:0947-5745
年代: 1993
DOI:10.1111/j.1439-0469.1993.tb00177.x
出版商: Blackwell Publishing Ltd
关键词: Crossopterygii;Skull;Development
数据来源: WILEY
摘要:
AbstractThe palatoquadrate inEusthenopterondisplays certain variation concerning the extent of its commissural lamina, and the presence of imprints of vessels and nerves on the outer surface of this middle part of the element. Comparison with some contemporary fishes revealed that branches of the arteria ophthalmica magna or of the ramus palatinus posterior VII could have produced these imprints. The grooves are connected with canals piercing the bone along its pars pterygoquadrata. Possible explanation is that the autopalatine and pterygoquadrate portions of the palatoquadrate were free in early developmental stages and later become interconnected by cartilage and bone. The dual nature of the palatoquadrate is shown to occur not only in the development of some Recent fishes, but in extinct groups (e. g., placoderms) as well.
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