Serendipaceratops arthurcclarkei is a VALID Early Cretaceous Ceratopsian?!

Serendipaceratops arthurcclarkei Rich & Vickers-Rich, 2003 is an Australian Early Cretaceous ceratopsian

Authors:

Rich et al

Abstract:

Serendipaceratops arthurcclarkei is one of Australia’s most enigmatic dinosaur taxa. Based on a single ulna recovered from Early Cretaceous high-latitude deposits in southeastern Australia, the fossil was originally classified as a neoceratopsian, but subsequently reassigned to Genasauria indet. because of comparisons with atypical thyreophorans. However, a morphometric and structural re-examination of the holotype indicates that it is proportionally distinguishable among dinosaurians and, indeed, manifests decisive statistical compatibility with ceratopsians. Statistical assessment similarly yields a synapomorphy that places the taxon robustly within Ceratopsia. Most certainly, identification of a unique differential character state combination renders S. arthurcclarkei as valid. Its affinity with ceratopsians concurs with proliferating records of other Laurasian dinosaur lineages from the Southern Hemisphere, and may reflect ancient Pangaean dispersals into or out of Gondwana.

Dinosaur Cove Site in Albanian Cretaceous Australia Has Landing Trackways From Flying Birds

Two fossilized footprints found at Dinosaur Cove in Victoria, Australia, were likely made by birds during the Early Cretaceous, making them the oldest known bird tracks in Australia.

The journal Palaeontology is publishing an analysis of the footprints led by Anthony Martin, a paleontologist at Emory University in Atlanta who specializes in trace fossils, which include tracks, burrows and nests. The study was co-authored by Patricia Vickers-Rich and Michael Hall of Monash University in Victoria and Thomas Rich of the Museum Victoria in Melbourne.

Much of the rocky coastal strata of Dinosaur Cove in southern Victoria were formed in river valleys in a polar climate during the Early Cretaceous. A great rift valley formed as the ancient supercontinent Gondwana broke up and Australia separated from Antarctica.

"These tracks are evidence that we had sizeable, flying birds living alongside other kinds of dinosaurs on these polar, river floodplains, about 105 million years ago," Martin says.

The thin-toed tracks in fluvial sandstone were likely made by two individual birds that were about the size of a great egret or a small heron, Martin says. Rear-pointing toes helped distinguish the tracks as avian, as opposed to a third nearby fossil track that was discovered at the same time, made by a non-avian theropod.

A long drag mark on one of the two bird tracks particularly interested Martin.

"I immediately knew what it was – a flight landing track – because I've seen many similar tracks made by egrets and herons on the sandy beaches of Georgia," Martin says.

Martin often leads student field trips to Georgia's coast and barrier islands, where he studies modern-day tracks and other life traces, to help him better identify fossil traces.

The ancient landing track from Australia "has a beautiful skid mark from the back toe dragging in the sand, likely caused as the bird was flapping its wings and coming in for a soft landing," Martin says. Fossils of landing tracks are rare, he adds, and could add to our understanding of the evolution of flight.

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