Australia has just added a new chapter to its complex history of paleontology. A recent study published in Journal of Vertebrate Paleontology It has been determined egg Excavations The oldest crocodile ever found in the country: Small shell fragments dating back about 55 million years, from the Morgon site in Queensland. This discovery was explained in detail by paleontologist Michael David Stein in an article for ConversationOffers Unpublished information around Mycosuchinos, A group of crocodiles that is now extinct Which has been a feature of Australia for tens of millions of years.
Morgon website is one of Most unique early Eocene fossil sites in Australia. Its exceptionally well-preserved sediments have provided a window into the ecosystem that evolved in the area about 55 million years ago, when wetlands and temporary waterways dominated the area. Among the fossils recovered It highlights birds, fish, turtles, salamanders and some of the continent’s first known marsupials. The presence of crocodile remains, and now also their eggs, confirms that this species They were an integral part of this ecosystem Warm and moist.
Exclusively Australian lineage
The heroes of this story are Mycosuchinosa unique Australian subspecies of crocodile that includes species widespread in locations such as Riversleigh and Alcoota. These animals Show anatomical differences Which reveals remarkable ecological diversity, including species with adaptations that indicate more terrestrial habits than today’s crocodiles. In Morgon, the only known way is Kambara, the only species of crocodile ever identified in the areaAnd from his presence It temporarily coincides with the shell fragments just described.
Study details that The fossils correspond to small fragments of eggshellsSome are less than a millimeter. for him The research is exceptional: Crocodile eggs It is rarely preserved Because their relatively fragile shells tend to disintegrate or decompose before they fossilize. Therefore, every part is found in Morgon Provides valuable information About the reproduction of mycosuchians and about the conditions of the environment in which they incubated their nests.
This is an unknown type of shell
Microscopic analysis has allowed us to determine that it is A The type of shell is not yet known. Researchers They have created a new ootaxonwhich is a formal type of fossil shell, called Wacaolithos goodtheelby, It has a microscopic structure that does not match modern crocodile eggs. Its inner layers offer features that allow it to clearly differentiate from existing styles and support its customization for Campara, The only form of crocodile found in Morgaon during this period. The reasoning is based on both the stratigraphy and the absence of other crocodilians in the area’s sediments.
Shrapnel too Provide clues about the reproductive biology of these animals. Shell structure with no signs of bacterial decomposition. It indicates that the eggs came from buried or semi-buried nests in moist environments. Characteristics of the sediments surrounding the shells suggest that mycosuchians may have used the margins of temporary bodies of water as egg-laying sites, a strategy partly shared with modern crocodilians, although there are notable differences in the microstructure of the shells.
Within the evolutionary path of Mycosuchinus
The environmental context of Morgon allows us to complete the picture. During the Early Eocene, the area was a mosaic of ponds, channels and floodplains with dense vegetation. In this environment, The kambara served as one of the main local predators. The combined presence of adults, juveniles and now egg fragments supports the hypothesis that the area served as a reproductive habitat, favoring the preservation of remains that are today considered essential for reconstructing the lives of these crocodilians.
The study also establishes this The discovery is within the evolutionary path of the Mycosuchiansa group that flourished during most of the Cenozoic Era, but He finally disappeared. The gradual desertification of Australia, coupled with changes in prey availability and profound environmental shifts, marked its decline. Murgon’s fragments help complete the chronology of this process and provide data on how these species reproduced on a continent whose climate and ecosystems at the time were very different from those of today.
About The Author
