A new noncalcified clasyclacialean alga from the Silurian of Wisconsin
Geography and Geology
Noncalcified thalli, consisting of a narrow main axis with numerous branched hairlike laterals in whorls and a subapical array of undivided clavate laterals, from the Silurian (Llandovery) Brandon Bridge Formation of southeastern Wisconsin, constitute the basis for a new genus and species of dasycladalean alga, Heterocladus waukeshaensis. A relationship within the family Triploporellaceae is indicated by the whorled arrangement of the laterals and the absence of gametophores on mature specimens. A compilation of occurrence data suggests that noncalcified dasyclads, as a whole, were more abundant and diverse during the Ordovician and Silurian than at any other time in their history. The heterocladous thallus architecture of this alga adds to a wide range of morphological variation documented among Ordovician and Silurian dasyclads, the sum of which indicates that Dasycladales underwent a significant evolutionary radiation during the early Paleozoic.
Link to Published Version
LoDuca, S. T., Kluessendorf, J., & Mikulic, D. G. (2003). A new noncalcified clasyclacialean alga from the Silurian of Wisconsin. Journal of Paleontology, 77(6), 1152–1158. doi:10.1666/0022-3360(2003)077<1152:ANNDAF>2.0.CO;2