THE TOMMOTIID KELANELLA AND ASSOCIATED FAUNA FROM THE EARLY CAMBRIAN OF SOUTHERN MONTAGNE NOIRE (FRANCE): IMPLICATIONS FOR CAMENELLAN PHYLOGENY

摘要: A carbonate bed of the Pardailhan Formation, early Cambrian, southern Montagne Noire (southern France), provided microfossils such as Hyolithellus sp., Torellella cf. mutila and sp. along with numerous disarticulated pieces composite skeletons valves brachiopod Eoobolus priscus bradoriid Monceretia erisylvia, chancelloriid sclerites (Chancelloria sp.). The assemblage also furnished a rich set from tommotiid Kelanella altaica. Five morphological variations latter have been identified. presence concentric ribs formed by distal inflation selected shell laminae in supports its assignment to camenellans. More particularly, transverse structures within internal cavity (septa) suggests close relationship Lapworthellidae. However, differ continuous variation their scleritome which is composed simple conical elements uniform ornamentation. Several forms are similar mitral sellate Camenella, whereas some other comparable Kennardia. new material that occupies transitional position between Lapworthellidae grouping Tommotiidae Kennardiidae. Such phylogenetic implies number sclerite morphotypes tends decrease camenellan during evolution.