FOSSIL ALGAE WERE VERY DIFFERENT FROM XENOPHYOPHORES

Pennsylvanian fossils of codiacean, coenocytic, green algae, commonly (but probably erroneously) called phylloid (blade or leaf-like) algae, have been proposed as being very similar to, and possible fossils of, deep-sea protoctistas known xenophyophores (bearers of foreign partic les; Maybury & Evans 1994). The major stimulus for this propos al seem s to be the absence in the fossil record of any other fossils that app ear to be clear xenophyophore progenitors. The evidence presented to s upport this resemblance includes a superficial similarity in morpholog y, especially between the xenophyophore Psammina and what is most like ly a species of the calcified green alga identified in several papers as Eugonophyllum, and high concentrations of barium sulfate in the xen ophyophores, and accumulations of barite associated with the fossil al gal thallus. The purpose of this paper is to describe briefly the morp hologies of xenophyophores and of the Paleozoic coenocytic fossil alga e in question. The two forms will then be compared, and finally, the e vidence offered for similarity will be examined.