Internal structures of Cyclocrinites dactioloides
Subtitle: a receptaculitid alga from the Lower Silurian of Iowa
By: Matthew H. Nitecki -- and Markes E. Johnson --.
Contributors: Johnson, Markes E. joint author; Field Museum of Natural History.
Series: Fieldiana -- v. 39, no. 1; Field Museum of Natural History. Publication 1280; Publication (Field Museum of Natural History) -- 1280.
Publisher: Field Museum of Natural History
Published: 1978
Place of publication: Chicago
Subjects: Algae, Fossil; Paleobotany -- Illinois.; Paleobotany -- Silurian; Paleobotany -- Iowa
Other titles: Cyclocrinites
Description: Cyclocrinites dactioloides is a marine, calcareous, receptacullitid alga which occurs as a common fossil in the Lower Silurian (Llandoverian Hopkinton Dolomite) of eastern Iowa and northwestern Illinios. The main axis and lateral branches, previously unknown in this species, are described. These internal parts, rarely known in other taxa of cyclocrinitids, were poorly calcified and hence were seldom preserved. The flattened lower parts of the thalli, previously considered resting surfaces, are now shown to result from post mortem, early diagenetic alterations. The lateral branches compare well with similar structures in both present-day dasyclads and in ischaditid receptaculitids and thus bridge the gap between these two separate orders of green algae.