© The Authors, 2009. Journal compilation © Australian Museum, Sydney, 2009 
Records of the Australian Museum (2009) Vol. 61: 1-30. ISSN 0067-1975 
doi:10.3853/j.0067-1975.61.2009.1520 
Biogeographic and Biostratigraphic Implications of the 
Serratognathus bilobatus Fauna (Conodonta) from the Emanuel 
Formation (Early Ordovician) of the Canning Basin, 
Western Australia 
Yong Yi Zhen 1 * and Robert S. Nicoll 2 
1 Australian Museum, 6 College Street, Sydney NSW 2010, Australia 
y ongy i. zhen @ austmus. go v. au 
2 Research School of Earth Science, Australian National University, Canberra ACT 0200, Australia 
bnicoll@goldweb.com.au 
Abstract. Discovery of Serratognathus bilobatus in the Early Ordovician Emanuel Formation of the Canning Basin, 
Western Australia, has regional biogeographic and biostratigraphic implications. Distribution of Serratognathus 
indicates a close biogeographic link between Australia and adjacent eastern Gondwanan plates and terranes during 
the latest Tremadocian to early Floian (Early Ordovician), and the formation of the so-called “Australasian Province”, 
a distinctive biogeographic entity that existed throughout most of the Ordovician. The S. bilobatus fauna from the 
Canning Basin is much more diverse in comparison with those assemblages bearing Serratognathus from coeval 
Chinese Lower Ordovician successions and probably represents an assemblage inhabiting relatively deeper water 
(mid-outer shelf) environments. The Canning Basin fauna contains many pandemic forms, and bridges the gap in 
the regional correlation of this widely distributed fauna across eastern Gondwana. 
This well-preserved, diverse fauna includes Serratognathus bilobatus and 23 associated species: Acodus deltatus?, 
Acodus? transitans, Bergstroemognathus extensus, Cornuodus sp., Drepanodus arcuatus, Drepanoistodus sp. cf. 
D. nowlani, Fahraeusodus adentatus, Lissoepikodus nudus, Nasusgnathus dolonus, Paltodus sp., Paracordylodus 
gracilis, Paroistodus parallelus, Paroistodusproteus, Prioniodus adami, Protopanderodus gradatus, Protoprioniodus 
simplicissimus, Scolopodus houlianzhaiensis, Semiacontiodus sp. cf. S. cornuformis, Stiptognathus borealis, 
Triangulodus bifidus, Tropodus australis , gen. et sp. indet. A and gen. et sp. B. A P. adami-S. bilobatus Biozone 
is defined within the middle and upper Emanuel Formation. Correlation of this biozone suggests an early Floian 
(late P. proteus Biozone to possibly earliest P elegans Biozone) age for the middle and upper members of the 
Emanuel Formation. 
Zhen, Yong Yi, & Robert S. Nicoll, 2009. Biogeographic and biostratigraphic implications of the Serratognathus bilobatus 
fauna (Conodonta) from the Emanuel Formation (Early Ordovician) of the Canning Basin, Western Australia. Records of the 
Australian Museum 61(1): 1-30. 
* author for correspondence 
