Psammornis ANDREWS , 1912

Pickford, Martin, Russell, Douglas & Day, Michael O., 2024, Nomination Of A Lectotype For The Avian Oospecies Psammornis Rothschildi Andrews, 1912, Fossil Imprint 80 (2), pp. 390-400 : 391

Genus Psammornis ANDREWS, 1912

Ty p e s p e c i e s. Psammornis rothschildi ANDREWS,

1912.

G e n u s d i a g n o s i s. Based on description by Andrews (1912): Eggshells in which the pore canals seem to be for the most part simple and run straight to the outer surface, where they open either singly or in small groups (sometimes in pairs) in very slight depressions. A few of the openings are very much larger than the rest. Outer layer divided into numerous layers by fine laminae of opaque material arranged parallel to the outer surface of the egg. Inner portion of shell … divided into innumerable small columns separated from one another by narrow cracks and small openings and terminated at the inner surface of the shell in rounded knobs … Each column may be more or less completely divided into secondary columns by dark vertical lines which tend to curve towards the inner end of the main columns... The whole shell is traversed by porecanals which originate in the spaces between the columns of the mammillary layer and run to the outer surface of the shell, either as simple straight tubes, or with more or less repeated branching as they approach the surface, where they open as small pores. Addendum: the external and internal structured layers of the eggshells are separated from each other by a fine-grained amorphous (spongy) layer. The external layer is about twice as thick as the amorphous layer, which is slightly thinner than the innermost layer.