The biodiversity and particularly the diversity of diatom floras of
coral reef environments are high. In spite of this, the
microphytobenthic communities of tropical reefs are poorly documented.
The Mascarene Archipelago, situated in the Indian Ocean near the
Tropic of Capricorn, includes the islands of Réunion, Mauritius and
Rodrigues. The coral sediments fringing the lagoons of the islands are
inhabited by diverse diatom communities, however, previous studies
mainly focussed on diatoms living in freshwater habitats of the
islands.
This monograph deals with the small-sized and so far poorly documented
taxa of order Achnanthales Silva found on coral reefs of Réunion and
Rodrigues Islands revealing their high diversity. The authors describe
59 taxa belonging to or related to the genera Achnanthes Bory sensu
stricto (2), Achnanthidium Kützing sensu Round (8), Amphicocconeis De
Stefano et Marino (2), Anorthoneis Grunow (1), Cocconeis Ehrenberg
(41), Planothidium Round et Bukhtiyarova (3), Vikingea Witkowski,
Lange-Bertalot et Metzeltin (2) and eight of these are new for
science. Genera and species are arranged alphabetically except taxa
with unfixed classification that are described at the end of the
taxonomic part. For each taxa taxonomic information, morphological
features (length, width, number of striae in 10 μm on both sternum and
raphe valva), descriptions in Latin and in English, as well as habitat
and comparison to other species are provided. Taxa are illustrated by
good quality, light and scanning electron microscopic micrographs. All
the 62 small-sized Achnanthales taxa observed during the four-year
survey are listed at the end of the monograph.
On the whole, this monograph is really valuable providing insight into
such a diverse, but previously hardly investigated tropical diatom
assemblage. It can be useful for all, who are interested either in the
diatoms living on coral reefs or in the small-sized representatives of
order Achnanthales.
M. DULEBA
Acta Botanica Hungarica 54 (3-4), 2012
