Cretaceous Diatoms: Morphology, Taxonomy, Biostratigraphy

Abstract

The Cretaceous record of the diatoms presented here outlines our understanding of their early morphological development. Recent documentation of well preserved Lower Cretaceous (Aptian/Albian) diatom assemblages provides a window into the early history of the diatoms and serves as a base for comparing their subsequent morphological changes. A brief review of diatom biology and morphology is provided to introduce this paper and that of Barron and Baldauf (this volume). Additional background information on the diatoms can be found in the works of Schrader and Schuette (1981), Tappan (1980), Bach and Burkhardt (1984), Barron (1985a, 1993), Fenner (1985), Ricard (1987), Bradbury (1988), Round et al. (1990), and Picket-Heaps et al. (1990).

A preliminary multigene phylogeny of the diatoms (Bacillariophyta): challenges for future research

“…More problematic is the fact that there are more extinct genera alone that probably belong to the radial centrics than there are genera in the most broadly sampled tree. Harwood & Nikolaev (1995) diagram the stratigraphic distribution of numerous probably radial centrics from the Upper and lower Cretaceous.…”

Biomineralization and Evolutionary History

“…Uncertainty plagues Rothpletz' (1896) report of diatoms in Middle Jurassic rocks, but unambiguous frustules occur in Lower Cretaceous marine rocks from many localities (Harwood and Nikolaev 1995). By late in the Cretaceous Period the group had both radiated in the oceans (Harwood and Nikolaev 1995) and colonized non-marine environments (Chacón-Baca et al 2002). The fossil record suggests that diatom diversity has continued to expand up to the present (Barron 1993).…”

Earliest freshwater diatoms from the Deccan Intertrappean (Maastrichtian) sediments of India

“…Utmost care was taken to avoid contamination; the rock samples were also processed at the University of Michigan for reconfirmation. Marine diatoms evolved as early as Early Jurassic (Rothpletz 1896) but gained diversity only during the period of Late Cretaceous (Strelnikova 1990;Harwood and Nikolaev 1995;Medlin et al 1996). This group has since then been established as an important group of primary producers in the marine ecosystem, besides being an important component in the silica cycle.…”

“…It is noteworthy to mention that both marine and non-marine diatoms are widely reported from the Tertiary deposits in India (Ghosh and Maitra 1947;Rao andAwasthi 1963: Gupta andKhandwelwal 1986). However, oldest marine diatoms are known from the Early Jurassic of Germany (Rothpletz 1896), and since Late Cretaceous onwards they are commonly reported (Hanna 1927;Bignot 1983;Harwood and Nikolaev 1995).…”