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Vernomanus Fossils Although the species in the Vernomanus genus have retained the same basic forms for 400 years, the fossil record traces changes as its species are challenged by climatic changes and varied habitats.
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From the collection of the Museum of Vegetable Physiology. |
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Pre-Permian
Vernomanus Most early Vernomanus fossils are of marine species showing a rigid segmented support structure. Although it is likely that other land species were evolving at this time, the rigid support and a preferred habitat of shallow inland seas contribute to a relatively abundant fossil record for these species. The marine Vernomanus species bear resemblance and shared habitat with the invertebrate crinoids, or “sea-lilies.”
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The
Dominance of Land Species After the Permian extinctions, marine species declined and the land species began to thrive in the drier, more arid climate. Most species of this period retain evidence of the segmented stem of its marine ancestors but also show spiny leaf-like structures. The function of these spiny protuberances is unknown—it could have been used either as a defense mechanism or as an aid in moisture-retention. Modern day aquatic species are thought to have evolved 50mya from land species rather than having direct connections to their marine ancestors.
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Ancestors
of Modern Day Species (6 million to present) At about 6 million years ago the smooth stemmed ancestors of modern day Vernomanus appeared. The fossil record of these species is sporadic due to their soft structured bodies.
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