A new radiolarian order - Archaeospicularia - is proposed for some Lower
Paleozoic radiolarians previously considered to belong to Spumellaria
and to Collodaria. It is characterized by a globular shell made of
several spicules which can be free, interlocked, or fused to formed a
latticed wall. The present paper gives the definition of this order and
proposes a first classification. It is supposed that the
Archaeospicularia represents the oldest radiolarian group and that in
the Lower Paleozoic it gave rise to the orders Entactinaria,
Albaillellaria, and probably Spumellaria by the reduction of the number
of initial spicules. The origin of this order and its relationships with
other groups of organisms with siliceous skeletons are also briefly
discussed. (C) 2000 Academie des sciences / Editions scientifiques et
medicales Elsevier SAS.