EARLY DEVELOPMENTAL EGGS WITH PERIVITELLINE SPACE FROM PRECAMBRIAN WENG''AN FAUNA, WENG''AN, CENTRAL GUIZHOU (SOUTH CHINA)
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Abstract:
Here we report the finding of eggs in 2 cell, 4 cell, 8 cell and 16 cell cleavage stages from Precambrian Doushantuo Formation, Weng'an, central Guizhou (Southern China). These eggs bearing a number of shared features suggest that they were derived from early animal belonging to the same species. These features include:same size; egg shell ornamented with identical structure; presence of perivitelline space; and equally holoblastic cleavage with spherical early cleavage cells. The identical eggs have been described as animal resting eggs by some authors and the presence of different cleavage stages indicates that they were developing eggs. Therefore, the resemblance with the resting eggs of some modern crustaceous forms in egg shell ornamentation can not be taken as a sign for their affinity. The perivitelline space mainly occurs in the eggs of modern bilaterians. The occurrence of the perivitelline space from 580 million years old eggs indicates that bilaterians might have evolved in a deeper time before Cambrian explosion.
