Marine organisms such as sponges and algae, along with primitive snails, clams, cephalopods and jawless fish called ostracoderms
, all suffered as a consequence.
A preliminary note on new ostracoderms
from the Lower Devonian (Emsian) of Central Poland.
The original vertebrates (possibly ostracoderms
) were active, predatory carnivores with metabolic signatures similar to most modern fish; the transition of vertebrates from aquatic to terrestrial habitats eventually enabled greater [O.sub.2] use, since [O.sub.2] in the aerial environment is more easily accessible given its increased diffusivity and concentration.
In 1976 Dineley and Loeffler published a monograph on ostracoderms
from the Delorme and associated formations in the Mackenzie Mountains, Canada.
The so-called 'Atholville Beds' (Dineley and Williams 1968), exposed at Campbellton and Atholville, have been examined by paleontologists since 1881 and have yielded ostracoderms
, arthrodires, acanthodians and chondrichthyans (Whiteaves 1881, 1889; Woodward 1889, 1892; Traquair 1890, 1893).