Article: Lamniform sharks of the mid Cretaceous Alinga Formation and Beedagong Claystone, Western Australia
The uppermost beds of the Alinga Formation and the basal part of the overlying Beedagong Claystone in the lower Murchison River area at the southern end of the Southern Carnarvon Basin, Western Australia, have yielded 15 species of lamniform sharks referred to ten genera, of which one genus and three species are new: Crietoxyrhina mantelli, Archaeolamna aff. kopingensis, A. haigi sp. nov., Leptostyrax sp., Cretolamna appendiculata. C. gunsoni sp. nov., Pseudoisurus tomosus. Pseudoisurus?. sp.. Paranomotodon sp,, 'Anomotodon' sp.. Johnlongia allocotodon gen. et sp, nov., Carcharias sp. A, C. sp. B, Squalicorax ex gr. curvatus. and S. volgensis. Direct correlation with Germany and the Saratov Province of the Russian Platform, using cosmopolitan lamnoids, dates the basal part of the Beedagong Claystone in the studied area as early or mid Cenomanian. The top of the Alinga Formation is provisionally placed in the early Cenomanian. This contrasts with the most recent previous estimate which suggested an early Turonian age for the upper half of the Alinga Formation. The present account is the first comprehensive documentation of Cretaceous selachians from Australia. It demonstrates the great potential of the use of lamniform shark teeth in intercontinental correlation of mid Cretaceous marine deposits.