Introduction

The first meeting of radiolarian micropaleontologists was organized in 1978 by P. De Wever (Lille, France). Most participants being from European universities, the name of "EuroRad" was coined to designate this meeting and the following ones. EuroRad II was held in 1980 (Basel, Switzerland) , EuroRad III in 1982 (Bergen, Norway), and EuroRad IV in 1984 (Leningrad, USSR). More and more radiolarists from all continents joining the EuroRad group, a formal international association of radiolarian micropaleontologists was created and its first meeting (InterRad V) was held in 1988 at Marburg (Germany) followed by InterRad VI in 1991 (Firenze, Italy), and Interrad VII in 1994 (Osaka, Japan).

The last InterRad VIII meeting (almost twenty years after Eurorad I) was held from September 8th to 13th (1997) at the Château de Bierville, a meeting centre located 50 kilometers South of Paris (France). 85 participants from 17 countries attended 8 workshops and presented 144 oral communications or posters. The abstracts of the communications were published in a special volume before the meeting, and further distributed to a total of 200 scientists. A one day special excursion was organized during InterRad VIII including a well-appreciated visit of a winery in the Loire area including some wine tasting, and a visit of the Château de Chambord, a gorgeous Renaissance castle. During the meeting, 23 papers were offered for publication in a special issue of Geodiversitas. A grand total of 21 manuscripts were received by the editorial committee and submitted to a pair review. Finally, 14 publications were selected and are presented in this volume.

Two years after InterRad VIII, this special issue of Geodiversitas cannot reflect the wide scope of the communications that encompassed all the geological record from Cambrian to Present. Original information is, however, given about significant advances in radiolarian biostratigraphy of Mesozoic formations of the Antartic and Pacific domains. New taxonomic descriptions of Paleozoic and Mesozoic forms are presented. A single paper is devoted to the radiolarians of the Messinian diatomites of the Mediterranean area. As usual, publication delay was longer than expected due to several reasons: some authors were late submitting their manuscript, some reviewers took a lengthy time to review manuscripts and answer successive requests from the editor. Modifications requested by reviewers took some extra time to be completed. Support from the CNRS, the Muséum national d'Histoire naturelle, the Ministère des Affaires étrangères and the Total Company is gratefully acknowledged.