The now-extinct mekosuchines(Mekosuchinae)were Australia’s own special, regional branch of the crocodile household.

These animals controlled inland waters of the continent 55 million years ago (Early Eocene date).

They belonged to the group of types that consists of alligators, real crocodiles, gharials and caiman.

Mekosuchines represent a much older branch than the saltwater and freshwater crocs discovered in Australia today.

The modern-day types made their method to the continent much later on, as it entered into contact with southeast Asia about 5 million years earlier.

Unlike today’s crocodiles, mekosuchines filled odd eco-friendly specific niches.

“It’s an unusual concept. Some of them appear to have actually been terrestrial hunters in the forests,” stated University of New South Wales Professor Michael Archer.

“There are recommendations of this throughout a vast array of more youthful mekosuchine fossils that were found previously within 25-million-year-old deposits from another area: the Riversleigh World Heritage Area, Boodjamulla National Park on Waanyi nation in northwestern Queensland.”

“Some riverine types there grew to a minimum of 5 m long. Some were likewise obviously a minimum of partially semi-arboreal ‘drop crocs’.”

“They were possibly searching like leopards– leaving of trees on any unwary thing they fancied for supper.”

The Wakkaoolithus godthelpi eggshells come from the earliest recognized member of the Mekosuchinae clade.

“These eggshells have actually provided us a peek of the intimate biography of mekosuchines,” stated Dr. Xavier Panadès i Blas, a paleontologist with the El Museu de la Conca Dellà, the Institut Català de Paleontologia Miquel Crusafont and the Universitat Autònoma de Barcelona.

“We can now examine not just the unusual anatomy of these crocs, however likewise how they replicated and adjusted to altering environments.”

The scientists analyzed the Wakkaoolithus godthelpi shell pieces under optical and electron microscopic lens.

Their microstructure recommends the crocs laid eggs on the margins of a lake, with their reproductive technique adjusting to rising and falling conditions.

“Mekosuchine crocs might have lost much of their inland area due to the fact that of trespassing dryland– ultimately needing to complete in the diminishing waterways not just with brand-new arrivals to Australia, however diminishing varieties of their megafaunal-sized victim too,” stated Dr. Michael Stein, a paleontologist at the University of New South Wales.

“The Murgon lake was surrounded by a lavish forest, which was likewise home to the world’s oldest-known songbirds, Australia’s earliest frogs and snakes, a wide variety of little mammals with South American links, in addition to among the world’s earliest recognized bats.”

According to the group, fossil eggshells are an underused resource in vertebrate paleontology.

“They maintain microstructural and geochemical signals that inform us not just what sort of animals laid them, however likewise where they embedded and how they reproduced,” Dr. Panadès i Blas stated.

“Our research study reveals simply how effective these pieces can be.”

“Eggshells need to be a regular, basic element of paleontological research study– gathered, curated and examined together with bones and teeth.”

The findings were released today in the Journal of Vertebrate Paleontology

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Xavier Panadès I Blas et alAustralia’s earliest crocodylian eggshell: insights into the reproductive paleoecology of mekosuchines. Journal of Vertebrate Paleontologyreleased online November 11, 2025; doi: 10.1080/ 02724634.2025.2560010