Format

Send to

Choose Destination
See comment in PubMed Commons below
Biol Lett. 2008 Feb 23;4(1):110-4.

Number and arrangement of extraocular muscles in primitive gnathostomes: evidence from extinct placoderm fishes.

Author information

1
Department of Earth and Marine Sciences, Australian National University, Canberra, Australian Capital Territory 0200, Australia. gyoung@ems.anu.edu.au

Abstract

Exceptional braincase preservation in some Devonian placoderm fishes permits interpretation of muscles and cranial nerves controlling eye movement. Placoderms are the only jawed vertebrates with anterior/posterior obliques as in the jawless lamprey, but with the same function as the superior/inferior obliques of other gnathostomes. Evidence of up to seven extraocular muscles suggests that this may be the primitive number for jawed vertebrates. Two muscles innervated by cranial nerve 6 suggest homologies with lampreys and tetrapods. If the extra muscle acquired by gnathostomes was the internal rectus, Devonian fossils show that it had a similar insertion above and behind the eyestalk in both placoderms and basal osteichthyans.

PMID:
18077236
PMCID:
PMC2413266
DOI:
10.1098/rsbl.2007.0545
[Indexed for MEDLINE]
Free PMC Article
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for HighWire Icon for PubMed Central
    Loading ...
    Support Center