01631nas a2200169 4500008004100000022001400041245011700055210006900172260000900241300000900250490000600259520098300265100002101248700001801269700003401287856014001321 2013 eng d a2041-172300aExceptional fossil preservation demonstrates a new mode of axial skeleton elongation in early ray-finned fishes.0 aExceptional fossil preservation demonstrates a new mode of axial c2013 a25700 v43 a
Elongate body plans have evolved independently multiple times in vertebrates, and involve either an increase in the number or in the length of the vertebrae. Here, we describe a new mechanism of body elongation in saurichthyids, an extinct group of elongate early ray-finned fishes. The rare preservation of soft tissue in a specimen of Saurichthys curionii from the Middle Triassic (Ladinian) of Switzerland provides significant new information on the relationship between the musculature and the skeleton. This new fossil material shows that elongation in these fishes results from doubling the number of neural arch-like elements per myomeric segment. This unique way of generating an elongate body plan demonstrates the evolutionary lability of the vertebral column in non-teleostean fishes. The shape and arrangement of preserved myosepta suggest that S. curionii was not a highly flexible fish, in spite of the increase in the number of neural arch-like elements.
1 aMaxwell, Erin, E1 aFurrer, Heinz1 aSánchez-Villagra, Marcelo, R uhttps://chondrichthyes.myspecies.info/content/exceptional-fossil-preservation-demonstrates-new-mode-axial-skeleton-elongation-early-ray