Abstract
The topmost Lancefieldian (La3, earliest Floian, Early Ordovician) Paratetragraptus approximatus Biozone of Victoria contains a previously undocumented graptolite fauna that includes, in addition to the nominative species, Paratetragraptus cooperi sp. nov., P. thomassmithi sp. nov., P. acclinans, P.? henrywilliamsi sp. nov., and Tshallograptus cymulus gen. et sp. nov., interpreted as the direct ancestor of Tshallograptus fruticosus (J. Hall). Taxa such as Kinnegraptus, Laxograptus, Pseudobryograptus, Phyllograptus, Tetragraptus and Loganograptus also make their first appearance in this zone. The succeeding Bendigonian stage, traditionally subdivided into four biozones using overlapping ranges of P. approximatus and the four- and three-stiped morphs of the T. fruticosus clade, is revised to accommodate the earlier than documented appearance of the 3-stiped morph, here renamed Tshallograptus tridens sp. nov., in the Be1 Biozone. The new subdivision consists of three biozones: Be1 P. approximatus + T. fruticosus Biozone, Be2+3 T. fruticosus + T. tridens Biozone, and Be4 T. tridens Biozone. T. tridens is vanishingly rare in Be1 and Be2 but appears in abundance in Be3 which is retained as a local subzone.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callSimilar Papers
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
