Dissocladella hauteriviana MASSE in MASSE et al., 1999 (non MASSE, 1976), another lower Urgonian Dasycladalean alga revisited

Abstract

First ascribed to the Triploporellacean genus Dissocladella (Pia in Rao & Pia, 1936), the species D. hauteriviana Masse in Masse et al., 1999, was supposedly characterized by a thallus bearing whorls of laterals each consisting of a stumpy primary with a tuft of four slim secondaries at its top. A restudy of the laterals proves that they split, not only once, but several times, and stepwisely decrease in diameter. The species is re-ascribed to the Family Thyrsoporellaceae in a new combination to the genus Deloffrella Granier & Michaud, 1987. Its known stratigraphic range is rather short (Late Valanginian-earliest Barremian). In addition, it disappears earlier than its companion Polyphysacean alga, i.e., Clypeina paucicalcarea (Conrad, 1970), and its geographical distribution is broader, which makes it a good index fossil for lower Urgonian carbonate platform series.