Origin of neck muscles in tetrapods

[Ben Creisler <bcreisler@gmail.com>]

From: Ben Creisler
bcreisler@gmail.com


A new non-dino paper that may be of interest:



Kate Trinajstic, Sophie Sanchez, Vincent Dupret, Paul Tafforeau, John
Long, Gavin Young, Tim Senden, Catherine Boisvert, Nicola Power, and
Per Erik Ahlberg (2013)
Fossil Musculature of the Most Primitive Jawed Vertebrates.
Science (advance online publication)
doi: 10.1126/science.1237275
http://www.sciencemag.org/content/early/2013/06/12/science.1237275.abstract

The transition from jawless to jawed vertebrates (gnathostomes)
resulted in the reconfiguration of the muscles and skeleton of the
head, including the creation of a separate shoulder girdle with
distinct neck muscles. We describe here the only known examples of
preserved musculature from placoderms (extinct armored fishes), the
phylogenetically most basal jawed vertebrates. Placoderms possess a
regionalized muscular anatomy differing radically from the musculature
of extant sharks, which is often viewed as primitive for gnathostomes.
The placoderm data suggest that neck musculature evolved together with
a dermal joint between skull and shoulder girdle, not as part of a
broadly flexible neck as in sharks, and that transverse abdominal
muscles are an innovation of gnathostomes rather than of tetrapods.