Late Paleozoic turrilepadid machaeridians from North America
Turrilepadids are not uncommon in late Paleozoic shales being often associated
with ostracodes, foraminifers, and minute molluscs. In North America they range
from the late Missippian (Chesterian) to early Permian (Leonardian). Sclerites of
the inner scleritome row are more common than outer sclerites. Some clusters
have been found. Sclerite consists of two layers with the thicker, lower layer
penetrated by a transverse tubular structures oriented perpendicular to the
sclerite surface, which may represent canals related to the papillae on the inner
surface of the sclerite. Turrilepas lepros sp. n., T. trigoniodes sp. n., T. asketos sp.
n., Clarkeolepis alloeospinosa sp. n., and Ambonlepidos petalos gen. et sp. n. are
Key words: Turrilepadidae, Machaeridia, Mississippian, Pennsylvanian, Permian.