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

作者：Granier Bruno^*

来源：Carnets de Geologie, 2013, 347-355.

DOI：10.4267/2042/53035

• Calcareous fossil algae
• Dasycladales
• Thyrsoporellaceae
• Deloffrella
• Hauterivian
• lowermost Barremian

First ascribed to the Triploporellacean genus Dissocladella (PIA in RAO %26 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 %26 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.

• 出版日期2013-12-25