Thomas H. Rich, Melissa Lowery, Michael Hall, Lesley Kool, Joseph Bevitt, Matt White & Patricia Vickers-Rich (2022): A new Cretaceous fossil mammal locality from the Bass Coast of southeastern Australia, Alcheringa: An Australasian Journal of Palaeontology, DOI: 10.1080/03115518.2022.2119600

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The paper describes a new fossil mammal locality in Honey Bay, approximately 450m south west of the Dinosaur Dreaming (Flat Rocks) site, where all the other mammal specimens have been collected along the Bass Coast.

The new mammal jaw (NMV P257142) was discovered by ace prospector Melissa Lowery who, along with local geologist Mike Cleeland, has found hundreds of fossil bones exposed on the surface of the rocky shore platform, which stretches from San Remo Back Beach to Inverloch.

As lead author Tom Rich points out in the paper, Mesozoic mammals from polar regions are extremely rare. Using cutting edge technology courtesy of Joseph Bevitt at the Australian Synchrotron, fellow palaeontologist Matt White was able to digitally reconstruct the tiny jaw to allow comparison of the single tooth in the new jaw with those of known fossil mammal teeth from the Flat Rocks site. This allowed Tom Rich to confirm that the latest jaw was consistent with the Ausktribosphenid taxon Ausktribosphenos nyktos.

 Although the two fossil mammal sites are located less than 500m apart they differ lithologically. Palynologist Barbara Wagstaff estimated the date of the Dinosaur Dreaming site to be around 126 million years (Wagstaff et al 2020) and although the authors are uncertain of the age of the Honey Bay locality, both localities are part of the Wonthaggi Formation, which encompasses the uppermost Barremian to lowermost Aptian.

The fossil layers at the Dinosaur Dreaming site consist of a clay intra-clast conglomerate overlain by a fluvial channel sandstone, whereas the sediments at the Honey Bay locality are made up of thick grit to very fine conglomerates as well as abundant coal and silicified wood that were originally transported onto a flood plain. The difference in sedimentary deposition between the two sites is significant and indicates that the Early Cretaceous fossils along the Bass Coast can be found in a variety of sediments.

 

Reference:

Barbara E. Wagstaff, Stephen J. Gallagher, W. Michael Hall, Vera A. Korasidis, Thomas H. Rich, Doris E. Seegets-Villiers & Patricia A. Vickers-Rich (2020): Palynological-age determination of Early Cretaceous vertebrate-bearing beds along the south Victorian coast of Australia, with implications for the spore-pollen biostratigraphy of the region, Alcheringa: An Australasian Journal of Palaeontology, DOI: 10.1080/03115518.2020.1754464