A. Soufiane et A. Achab, Chitinozoan zonation of the Late Ordovician and the Early Silurian of the Island of Anticosti, Quebec, Canada, REV PALAE P, 109(2), 2000, pp. 85-111
A reappraisal of chitinozoan distribution across the Ordovician-Silurian bo
undary on the Island of Anticosti has led to the recognition of a new zone,
the Ancyrochitina ellisbayensis biozone, in the uppermost part of the Elli
s Bay Formation. This biozone lies between the well defined Upper Ordovicia
n Spinachitina taugourdeaui biozone and the lowest Silurian (Rhuddanian) Pl
ectochitina nodifera biozone of the Becscie Formation. The occurrence of su
ch diagnostic species as P. nodifera, Belonechitina postrobusta, Conochitin
a electa and Ancyrochitina ramosaspina in the Lower Silurian of Anticosti p
oints to a close similarity to faunas in Estonia and north Latvia and indic
ates an age ranging from the Parakidograptus acuminatus to the Coronograptu
s cyphus in terms of graptolite zones. The chitinozoan biozonation harmoniz
es with that based on conodonts and, to a lesser extent, with the known gra
ptolite faunal succession. Five new species: Ancyrochitina ellisbayensis sp
. nov., Clathrochitina postconcinna sp. nov., Conochitina gunriveris sp. no
v., Clathrochitina perexilis sp. nov., Bursachitina basiconcava sp. nov, an
d three species in open nomenclature are described. (C) 2000 Elsevier Scien
ce B.V. All rights reserved.