galeaspid

plural galeaspids

1. Any of the extinct class †Galeaspida of jawless fish.

   Some 70 million years after this particular galeaspid swam the oceans, fish made another evolutionary leap when they took to life on land.

   2013 February 16, Jeff Hecht, “Evolution's detectives: Closing in on missing links”, in New Scientist, volume 217, number 2904, page 37

   2 more examples

   An interesting example is provided by the “polybranchic” condition in extinct jawless vertebrate taxa, which display an extremely large number of gills, such as some early Devonian galeaspids and the late Devonian euphaneropids.

   2007, David J. McKenzie, Anthony P. Farrell, Colin J. Brauner, Fish Physiology: Volume 26: Primitive Fishes, page 41

   The jawless fish (termed ‘agnathans’) evolved and flourished during the Silurian Period (435-410 million years ago). These included bizarre forms with weird bony head armours, such as the bizarre galeaspids from China and the pituriaspids from Australia.

   2011, Jeffrey Stilwell, John Long, Frozen in Time: Prehistoric Life in Antarctica, page 64