Archecyrtiidae fam. n. Jurassic radiolarians from Bulgaria and some regions of the USSR

pp. 65-75

New radiolarians of the order Nassellaria have been found in Dobridol Formation (Lower Jurassic) of SW Bulgaria. The original morphology of skeleton constructions allows for the definition of a new high-rank taxon - Archecyrtoidea superfam. n. Its representatives were supposedly the ancestral forms for several superfamilies of Nassellaria. In the evolution process of Early Mesоzoic nassellarians a partial reduction of proximal and distal parts of their skeletons together with simultaneous finishing of cephalis formation and perfectioning of chamber walls by ordering of the porous structure took place. Three morphological groups may be subdivided and they may be regarded as potential new families. Their representatives are widespread in the Tethys region: they have been observed also on the territory of the Soviet Union in Lesser Caucasus (Lower Jurassic) and in the Far East of the USSR (Upper Triassic? - Lower Jurassic). The present paper contains the description of 23 new species of eight genera of Archecyrtiidae fam. n.: Archecampe orciformis sp. n., Archecampe sufflata sp. n., Archecyrtum concavum sp. n., Archecyrtum concinnum sp. n., Archecyrturn dobridolicum sp. n., Archecyrtum exsertum sp. n., Archecyrtum gurosum sp. n., Archecyrtum modicum sp. n., Archecyrtum strumensis sp. n., Archeeucyrtis fragilis sp. n., Archeeucyrtis spiralis sp. n., Archeeucyrlis uinbonatus sp. n., Archefusus auctus sp. n., Archefusus fusiformis sp. n., Archefusus (?) sp. A, Archemints daedalus sp. n., Archesomus katensis sp. n., Archestrumus cribrosus sp. n., Archestrurnus cuspidatus sp. n., Archestrumus expansus sp. n., Archelypum botryosum sp. n., Archetypum elongatum sp. n., Archetypum erectum sp. n., Archetypum punctulatum sp. n. Archetypum (?) sp. A.